// SPDX-License-Identifier: GPL-2.0 /* * Shared application/kernel submission and completion ring pairs, for * supporting fast/efficient IO. * * A note on the read/write ordering memory barriers that are matched between * the application and kernel side. * * After the application reads the CQ ring tail, it must use an * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses * before writing the tail (using smp_load_acquire to read the tail will * do). It also needs a smp_mb() before updating CQ head (ordering the * entry load(s) with the head store), pairing with an implicit barrier * through a control-dependency in io_get_cqring (smp_store_release to * store head will do). Failure to do so could lead to reading invalid * CQ entries. * * Likewise, the application must use an appropriate smp_wmb() before * writing the SQ tail (ordering SQ entry stores with the tail store), * which pairs with smp_load_acquire in io_get_sqring (smp_store_release * to store the tail will do). And it needs a barrier ordering the SQ * head load before writing new SQ entries (smp_load_acquire to read * head will do). * * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after* * updating the SQ tail; a full memory barrier smp_mb() is needed * between. * * Also see the examples in the liburing library: * * git://git.kernel.dk/liburing * * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens * from data shared between the kernel and application. This is done both * for ordering purposes, but also to ensure that once a value is loaded from * data that the application could potentially modify, it remains stable. * * Copyright (C) 2018-2019 Jens Axboe * Copyright (c) 2018-2019 Christoph Hellwig */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include #include #include "internal.h" #include "io-wq.h" #define IORING_MAX_ENTRIES 32768 #define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES) /* * Shift of 9 is 512 entries, or exactly one page on 64-bit archs */ #define IORING_FILE_TABLE_SHIFT 9 #define IORING_MAX_FILES_TABLE (1U << IORING_FILE_TABLE_SHIFT) #define IORING_FILE_TABLE_MASK (IORING_MAX_FILES_TABLE - 1) #define IORING_MAX_FIXED_FILES (64 * IORING_MAX_FILES_TABLE) #define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \ IORING_REGISTER_LAST + IORING_OP_LAST) struct io_uring { u32 head ____cacheline_aligned_in_smp; u32 tail ____cacheline_aligned_in_smp; }; /* * This data is shared with the application through the mmap at offsets * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING. * * The offsets to the member fields are published through struct * io_sqring_offsets when calling io_uring_setup. */ struct io_rings { /* * Head and tail offsets into the ring; the offsets need to be * masked to get valid indices. * * The kernel controls head of the sq ring and the tail of the cq ring, * and the application controls tail of the sq ring and the head of the * cq ring. */ struct io_uring sq, cq; /* * Bitmasks to apply to head and tail offsets (constant, equals * ring_entries - 1) */ u32 sq_ring_mask, cq_ring_mask; /* Ring sizes (constant, power of 2) */ u32 sq_ring_entries, cq_ring_entries; /* * Number of invalid entries dropped by the kernel due to * invalid index stored in array * * Written by the kernel, shouldn't be modified by the * application (i.e. get number of "new events" by comparing to * cached value). * * After a new SQ head value was read by the application this * counter includes all submissions that were dropped reaching * the new SQ head (and possibly more). */ u32 sq_dropped; /* * Runtime SQ flags * * Written by the kernel, shouldn't be modified by the * application. * * The application needs a full memory barrier before checking * for IORING_SQ_NEED_WAKEUP after updating the sq tail. */ u32 sq_flags; /* * Runtime CQ flags * * Written by the application, shouldn't be modified by the * kernel. */ u32 cq_flags; /* * Number of completion events lost because the queue was full; * this should be avoided by the application by making sure * there are not more requests pending than there is space in * the completion queue. * * Written by the kernel, shouldn't be modified by the * application (i.e. get number of "new events" by comparing to * cached value). * * As completion events come in out of order this counter is not * ordered with any other data. */ u32 cq_overflow; /* * Ring buffer of completion events. * * The kernel writes completion events fresh every time they are * produced, so the application is allowed to modify pending * entries. */ struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp; }; enum io_uring_cmd_flags { IO_URING_F_NONBLOCK = 1, IO_URING_F_COMPLETE_DEFER = 2, }; struct io_mapped_ubuf { u64 ubuf; size_t len; struct bio_vec *bvec; unsigned int nr_bvecs; unsigned long acct_pages; }; struct io_ring_ctx; struct io_rsrc_put { struct list_head list; union { void *rsrc; struct file *file; }; }; struct fixed_rsrc_table { struct file **files; }; struct fixed_rsrc_ref_node { struct percpu_ref refs; struct list_head node; struct list_head rsrc_list; struct fixed_rsrc_data *rsrc_data; void (*rsrc_put)(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc); struct llist_node llist; bool done; }; struct fixed_rsrc_data { struct fixed_rsrc_table *table; struct io_ring_ctx *ctx; struct fixed_rsrc_ref_node *node; struct percpu_ref refs; struct completion done; }; struct io_buffer { struct list_head list; __u64 addr; __s32 len; __u16 bid; }; struct io_restriction { DECLARE_BITMAP(register_op, IORING_REGISTER_LAST); DECLARE_BITMAP(sqe_op, IORING_OP_LAST); u8 sqe_flags_allowed; u8 sqe_flags_required; bool registered; }; struct io_sq_data { refcount_t refs; struct mutex lock; /* ctx's that are using this sqd */ struct list_head ctx_list; struct list_head ctx_new_list; struct mutex ctx_lock; struct task_struct *thread; struct wait_queue_head wait; unsigned sq_thread_idle; }; #define IO_IOPOLL_BATCH 8 #define IO_COMPL_BATCH 32 #define IO_REQ_CACHE_SIZE 32 #define IO_REQ_ALLOC_BATCH 8 struct io_comp_state { struct io_kiocb *reqs[IO_COMPL_BATCH]; unsigned int nr; unsigned int locked_free_nr; /* inline/task_work completion list, under ->uring_lock */ struct list_head free_list; /* IRQ completion list, under ->completion_lock */ struct list_head locked_free_list; }; struct io_submit_state { struct blk_plug plug; /* * io_kiocb alloc cache */ void *reqs[IO_REQ_CACHE_SIZE]; unsigned int free_reqs; bool plug_started; /* * Batch completion logic */ struct io_comp_state comp; /* * File reference cache */ struct file *file; unsigned int fd; unsigned int file_refs; unsigned int ios_left; }; struct io_ring_ctx { struct { struct percpu_ref refs; } ____cacheline_aligned_in_smp; struct { unsigned int flags; unsigned int compat: 1; unsigned int limit_mem: 1; unsigned int cq_overflow_flushed: 1; unsigned int drain_next: 1; unsigned int eventfd_async: 1; unsigned int restricted: 1; unsigned int sqo_dead: 1; /* * Ring buffer of indices into array of io_uring_sqe, which is * mmapped by the application using the IORING_OFF_SQES offset. * * This indirection could e.g. be used to assign fixed * io_uring_sqe entries to operations and only submit them to * the queue when needed. * * The kernel modifies neither the indices array nor the entries * array. */ u32 *sq_array; unsigned cached_sq_head; unsigned sq_entries; unsigned sq_mask; unsigned sq_thread_idle; unsigned cached_sq_dropped; unsigned cached_cq_overflow; unsigned long sq_check_overflow; struct list_head defer_list; struct list_head timeout_list; struct list_head cq_overflow_list; struct io_uring_sqe *sq_sqes; } ____cacheline_aligned_in_smp; struct { struct mutex uring_lock; wait_queue_head_t wait; } ____cacheline_aligned_in_smp; struct io_submit_state submit_state; struct io_rings *rings; /* IO offload */ struct io_wq *io_wq; /* * For SQPOLL usage - we hold a reference to the parent task, so we * have access to the ->files */ struct task_struct *sqo_task; /* Only used for accounting purposes */ struct mm_struct *mm_account; #ifdef CONFIG_BLK_CGROUP struct cgroup_subsys_state *sqo_blkcg_css; #endif struct io_sq_data *sq_data; /* if using sq thread polling */ struct wait_queue_head sqo_sq_wait; struct list_head sqd_list; /* * If used, fixed file set. Writers must ensure that ->refs is dead, * readers must ensure that ->refs is alive as long as the file* is * used. Only updated through io_uring_register(2). */ struct fixed_rsrc_data *file_data; unsigned nr_user_files; /* if used, fixed mapped user buffers */ unsigned nr_user_bufs; struct io_mapped_ubuf *user_bufs; struct user_struct *user; const struct cred *creds; #ifdef CONFIG_AUDIT kuid_t loginuid; unsigned int sessionid; #endif struct completion ref_comp; struct completion sq_thread_comp; #if defined(CONFIG_UNIX) struct socket *ring_sock; #endif struct idr io_buffer_idr; struct idr personality_idr; struct { unsigned cached_cq_tail; unsigned cq_entries; unsigned cq_mask; atomic_t cq_timeouts; unsigned cq_last_tm_flush; unsigned long cq_check_overflow; struct wait_queue_head cq_wait; struct fasync_struct *cq_fasync; struct eventfd_ctx *cq_ev_fd; } ____cacheline_aligned_in_smp; struct { spinlock_t completion_lock; /* * ->iopoll_list is protected by the ctx->uring_lock for * io_uring instances that don't use IORING_SETUP_SQPOLL. * For SQPOLL, only the single threaded io_sq_thread() will * manipulate the list, hence no extra locking is needed there. */ struct list_head iopoll_list; struct hlist_head *cancel_hash; unsigned cancel_hash_bits; bool poll_multi_file; spinlock_t inflight_lock; struct list_head inflight_list; } ____cacheline_aligned_in_smp; struct delayed_work rsrc_put_work; struct llist_head rsrc_put_llist; struct list_head rsrc_ref_list; spinlock_t rsrc_ref_lock; struct io_restriction restrictions; /* Keep this last, we don't need it for the fast path */ struct work_struct exit_work; }; /* * First field must be the file pointer in all the * iocb unions! See also 'struct kiocb' in */ struct io_poll_iocb { struct file *file; struct wait_queue_head *head; __poll_t events; bool done; bool canceled; struct wait_queue_entry wait; }; struct io_poll_remove { struct file *file; u64 addr; }; struct io_close { struct file *file; int fd; }; struct io_timeout_data { struct io_kiocb *req; struct hrtimer timer; struct timespec64 ts; enum hrtimer_mode mode; }; struct io_accept { struct file *file; struct sockaddr __user *addr; int __user *addr_len; int flags; unsigned long nofile; }; struct io_sync { struct file *file; loff_t len; loff_t off; int flags; int mode; }; struct io_cancel { struct file *file; u64 addr; }; struct io_timeout { struct file *file; u32 off; u32 target_seq; struct list_head list; /* head of the link, used by linked timeouts only */ struct io_kiocb *head; }; struct io_timeout_rem { struct file *file; u64 addr; /* timeout update */ struct timespec64 ts; u32 flags; }; struct io_rw { /* NOTE: kiocb has the file as the first member, so don't do it here */ struct kiocb kiocb; u64 addr; u64 len; }; struct io_connect { struct file *file; struct sockaddr __user *addr; int addr_len; }; struct io_sr_msg { struct file *file; union { struct user_msghdr __user *umsg; void __user *buf; }; int msg_flags; int bgid; size_t len; struct io_buffer *kbuf; }; struct io_open { struct file *file; int dfd; struct filename *filename; struct open_how how; unsigned long nofile; }; struct io_rsrc_update { struct file *file; u64 arg; u32 nr_args; u32 offset; }; struct io_fadvise { struct file *file; u64 offset; u32 len; u32 advice; }; struct io_madvise { struct file *file; u64 addr; u32 len; u32 advice; }; struct io_epoll { struct file *file; int epfd; int op; int fd; struct epoll_event event; }; struct io_splice { struct file *file_out; struct file *file_in; loff_t off_out; loff_t off_in; u64 len; unsigned int flags; }; struct io_provide_buf { struct file *file; __u64 addr; __s32 len; __u32 bgid; __u16 nbufs; __u16 bid; }; struct io_statx { struct file *file; int dfd; unsigned int mask; unsigned int flags; const char __user *filename; struct statx __user *buffer; }; struct io_shutdown { struct file *file; int how; }; struct io_rename { struct file *file; int old_dfd; int new_dfd; struct filename *oldpath; struct filename *newpath; int flags; }; struct io_unlink { struct file *file; int dfd; int flags; struct filename *filename; }; struct io_completion { struct file *file; struct list_head list; int cflags; }; struct io_async_connect { struct sockaddr_storage address; }; struct io_async_msghdr { struct iovec fast_iov[UIO_FASTIOV]; /* points to an allocated iov, if NULL we use fast_iov instead */ struct iovec *free_iov; struct sockaddr __user *uaddr; struct msghdr msg; struct sockaddr_storage addr; }; struct io_async_rw { struct iovec fast_iov[UIO_FASTIOV]; const struct iovec *free_iovec; struct iov_iter iter; size_t bytes_done; struct wait_page_queue wpq; }; enum { REQ_F_FIXED_FILE_BIT = IOSQE_FIXED_FILE_BIT, REQ_F_IO_DRAIN_BIT = IOSQE_IO_DRAIN_BIT, REQ_F_LINK_BIT = IOSQE_IO_LINK_BIT, REQ_F_HARDLINK_BIT = IOSQE_IO_HARDLINK_BIT, REQ_F_FORCE_ASYNC_BIT = IOSQE_ASYNC_BIT, REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT, REQ_F_FAIL_LINK_BIT, REQ_F_INFLIGHT_BIT, REQ_F_CUR_POS_BIT, REQ_F_NOWAIT_BIT, REQ_F_LINK_TIMEOUT_BIT, REQ_F_ISREG_BIT, REQ_F_NEED_CLEANUP_BIT, REQ_F_POLLED_BIT, REQ_F_BUFFER_SELECTED_BIT, REQ_F_NO_FILE_TABLE_BIT, REQ_F_WORK_INITIALIZED_BIT, REQ_F_LTIMEOUT_ACTIVE_BIT, REQ_F_COMPLETE_INLINE_BIT, /* not a real bit, just to check we're not overflowing the space */ __REQ_F_LAST_BIT, }; enum { /* ctx owns file */ REQ_F_FIXED_FILE = BIT(REQ_F_FIXED_FILE_BIT), /* drain existing IO first */ REQ_F_IO_DRAIN = BIT(REQ_F_IO_DRAIN_BIT), /* linked sqes */ REQ_F_LINK = BIT(REQ_F_LINK_BIT), /* doesn't sever on completion < 0 */ REQ_F_HARDLINK = BIT(REQ_F_HARDLINK_BIT), /* IOSQE_ASYNC */ REQ_F_FORCE_ASYNC = BIT(REQ_F_FORCE_ASYNC_BIT), /* IOSQE_BUFFER_SELECT */ REQ_F_BUFFER_SELECT = BIT(REQ_F_BUFFER_SELECT_BIT), /* fail rest of links */ REQ_F_FAIL_LINK = BIT(REQ_F_FAIL_LINK_BIT), /* on inflight list */ REQ_F_INFLIGHT = BIT(REQ_F_INFLIGHT_BIT), /* read/write uses file position */ REQ_F_CUR_POS = BIT(REQ_F_CUR_POS_BIT), /* must not punt to workers */ REQ_F_NOWAIT = BIT(REQ_F_NOWAIT_BIT), /* has or had linked timeout */ REQ_F_LINK_TIMEOUT = BIT(REQ_F_LINK_TIMEOUT_BIT), /* regular file */ REQ_F_ISREG = BIT(REQ_F_ISREG_BIT), /* needs cleanup */ REQ_F_NEED_CLEANUP = BIT(REQ_F_NEED_CLEANUP_BIT), /* already went through poll handler */ REQ_F_POLLED = BIT(REQ_F_POLLED_BIT), /* buffer already selected */ REQ_F_BUFFER_SELECTED = BIT(REQ_F_BUFFER_SELECTED_BIT), /* doesn't need file table for this request */ REQ_F_NO_FILE_TABLE = BIT(REQ_F_NO_FILE_TABLE_BIT), /* io_wq_work is initialized */ REQ_F_WORK_INITIALIZED = BIT(REQ_F_WORK_INITIALIZED_BIT), /* linked timeout is active, i.e. prepared by link's head */ REQ_F_LTIMEOUT_ACTIVE = BIT(REQ_F_LTIMEOUT_ACTIVE_BIT), /* completion is deferred through io_comp_state */ REQ_F_COMPLETE_INLINE = BIT(REQ_F_COMPLETE_INLINE_BIT), }; struct async_poll { struct io_poll_iocb poll; struct io_poll_iocb *double_poll; }; struct io_task_work { struct io_wq_work_node node; task_work_func_t func; }; /* * NOTE! Each of the iocb union members has the file pointer * as the first entry in their struct definition. So you can * access the file pointer through any of the sub-structs, * or directly as just 'ki_filp' in this struct. */ struct io_kiocb { union { struct file *file; struct io_rw rw; struct io_poll_iocb poll; struct io_poll_remove poll_remove; struct io_accept accept; struct io_sync sync; struct io_cancel cancel; struct io_timeout timeout; struct io_timeout_rem timeout_rem; struct io_connect connect; struct io_sr_msg sr_msg; struct io_open open; struct io_close close; struct io_rsrc_update rsrc_update; struct io_fadvise fadvise; struct io_madvise madvise; struct io_epoll epoll; struct io_splice splice; struct io_provide_buf pbuf; struct io_statx statx; struct io_shutdown shutdown; struct io_rename rename; struct io_unlink unlink; /* use only after cleaning per-op data, see io_clean_op() */ struct io_completion compl; }; /* opcode allocated if it needs to store data for async defer */ void *async_data; u8 opcode; /* polled IO has completed */ u8 iopoll_completed; u16 buf_index; u32 result; struct io_ring_ctx *ctx; unsigned int flags; refcount_t refs; struct task_struct *task; u64 user_data; struct io_kiocb *link; struct percpu_ref *fixed_rsrc_refs; /* * 1. used with ctx->iopoll_list with reads/writes * 2. to track reqs with ->files (see io_op_def::file_table) */ struct list_head inflight_entry; union { struct io_task_work io_task_work; struct callback_head task_work; }; /* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */ struct hlist_node hash_node; struct async_poll *apoll; struct io_wq_work work; }; struct io_defer_entry { struct list_head list; struct io_kiocb *req; u32 seq; }; struct io_op_def { /* needs req->file assigned */ unsigned needs_file : 1; /* hash wq insertion if file is a regular file */ unsigned hash_reg_file : 1; /* unbound wq insertion if file is a non-regular file */ unsigned unbound_nonreg_file : 1; /* opcode is not supported by this kernel */ unsigned not_supported : 1; /* set if opcode supports polled "wait" */ unsigned pollin : 1; unsigned pollout : 1; /* op supports buffer selection */ unsigned buffer_select : 1; /* must always have async data allocated */ unsigned needs_async_data : 1; /* should block plug */ unsigned plug : 1; /* size of async data needed, if any */ unsigned short async_size; unsigned work_flags; }; static const struct io_op_def io_op_defs[] = { [IORING_OP_NOP] = {}, [IORING_OP_READV] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, .needs_async_data = 1, .plug = 1, .async_size = sizeof(struct io_async_rw), .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG, }, [IORING_OP_WRITEV] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .needs_async_data = 1, .plug = 1, .async_size = sizeof(struct io_async_rw), .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG | IO_WQ_WORK_FSIZE, }, [IORING_OP_FSYNC] = { .needs_file = 1, .work_flags = IO_WQ_WORK_BLKCG, }, [IORING_OP_READ_FIXED] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .plug = 1, .async_size = sizeof(struct io_async_rw), .work_flags = IO_WQ_WORK_BLKCG | IO_WQ_WORK_MM, }, [IORING_OP_WRITE_FIXED] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .plug = 1, .async_size = sizeof(struct io_async_rw), .work_flags = IO_WQ_WORK_BLKCG | IO_WQ_WORK_FSIZE | IO_WQ_WORK_MM, }, [IORING_OP_POLL_ADD] = { .needs_file = 1, .unbound_nonreg_file = 1, }, [IORING_OP_POLL_REMOVE] = {}, [IORING_OP_SYNC_FILE_RANGE] = { .needs_file = 1, .work_flags = IO_WQ_WORK_BLKCG, }, [IORING_OP_SENDMSG] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .needs_async_data = 1, .async_size = sizeof(struct io_async_msghdr), .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG, }, [IORING_OP_RECVMSG] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, .needs_async_data = 1, .async_size = sizeof(struct io_async_msghdr), .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG, }, [IORING_OP_TIMEOUT] = { .needs_async_data = 1, .async_size = sizeof(struct io_timeout_data), .work_flags = IO_WQ_WORK_MM, }, [IORING_OP_TIMEOUT_REMOVE] = { /* used by timeout updates' prep() */ .work_flags = IO_WQ_WORK_MM, }, [IORING_OP_ACCEPT] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_FILES, }, [IORING_OP_ASYNC_CANCEL] = {}, [IORING_OP_LINK_TIMEOUT] = { .needs_async_data = 1, .async_size = sizeof(struct io_timeout_data), .work_flags = IO_WQ_WORK_MM, }, [IORING_OP_CONNECT] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .needs_async_data = 1, .async_size = sizeof(struct io_async_connect), .work_flags = IO_WQ_WORK_MM, }, [IORING_OP_FALLOCATE] = { .needs_file = 1, .work_flags = IO_WQ_WORK_BLKCG | IO_WQ_WORK_FSIZE, }, [IORING_OP_OPENAT] = { .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_BLKCG | IO_WQ_WORK_FS | IO_WQ_WORK_MM, }, [IORING_OP_CLOSE] = { .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_BLKCG, }, [IORING_OP_FILES_UPDATE] = { .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_MM, }, [IORING_OP_STATX] = { .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_MM | IO_WQ_WORK_FS | IO_WQ_WORK_BLKCG, }, [IORING_OP_READ] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, .plug = 1, .async_size = sizeof(struct io_async_rw), .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG, }, [IORING_OP_WRITE] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .plug = 1, .async_size = sizeof(struct io_async_rw), .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG | IO_WQ_WORK_FSIZE, }, [IORING_OP_FADVISE] = { .needs_file = 1, .work_flags = IO_WQ_WORK_BLKCG, }, [IORING_OP_MADVISE] = { .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG, }, [IORING_OP_SEND] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG, }, [IORING_OP_RECV] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG, }, [IORING_OP_OPENAT2] = { .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_FS | IO_WQ_WORK_BLKCG | IO_WQ_WORK_MM, }, [IORING_OP_EPOLL_CTL] = { .unbound_nonreg_file = 1, .work_flags = IO_WQ_WORK_FILES, }, [IORING_OP_SPLICE] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .work_flags = IO_WQ_WORK_BLKCG, }, [IORING_OP_PROVIDE_BUFFERS] = {}, [IORING_OP_REMOVE_BUFFERS] = {}, [IORING_OP_TEE] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, }, [IORING_OP_SHUTDOWN] = { .needs_file = 1, }, [IORING_OP_RENAMEAT] = { .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_FILES | IO_WQ_WORK_FS | IO_WQ_WORK_BLKCG, }, [IORING_OP_UNLINKAT] = { .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_FILES | IO_WQ_WORK_FS | IO_WQ_WORK_BLKCG, }, }; static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx, struct task_struct *task, struct files_struct *files); static void destroy_fixed_rsrc_ref_node(struct fixed_rsrc_ref_node *ref_node); static struct fixed_rsrc_ref_node *alloc_fixed_rsrc_ref_node( struct io_ring_ctx *ctx); static void init_fixed_file_ref_node(struct io_ring_ctx *ctx, struct fixed_rsrc_ref_node *ref_node); static bool io_rw_reissue(struct io_kiocb *req); static void io_cqring_fill_event(struct io_kiocb *req, long res); static void io_put_req(struct io_kiocb *req); static void io_put_req_deferred(struct io_kiocb *req, int nr); static void io_double_put_req(struct io_kiocb *req); static void io_dismantle_req(struct io_kiocb *req); static void io_put_task(struct task_struct *task, int nr); static void io_queue_next(struct io_kiocb *req); static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req); static void __io_queue_linked_timeout(struct io_kiocb *req); static void io_queue_linked_timeout(struct io_kiocb *req); static int __io_sqe_files_update(struct io_ring_ctx *ctx, struct io_uring_rsrc_update *ip, unsigned nr_args); static void __io_clean_op(struct io_kiocb *req); static struct file *io_file_get(struct io_submit_state *state, struct io_kiocb *req, int fd, bool fixed); static void __io_queue_sqe(struct io_kiocb *req); static void io_rsrc_put_work(struct work_struct *work); static int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, struct iov_iter *iter, bool needs_lock); static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec, const struct iovec *fast_iov, struct iov_iter *iter, bool force); static void io_req_task_queue(struct io_kiocb *req); static void io_submit_flush_completions(struct io_comp_state *cs, struct io_ring_ctx *ctx); static struct kmem_cache *req_cachep; static const struct file_operations io_uring_fops; struct sock *io_uring_get_socket(struct file *file) { #if defined(CONFIG_UNIX) if (file->f_op == &io_uring_fops) { struct io_ring_ctx *ctx = file->private_data; return ctx->ring_sock->sk; } #endif return NULL; } EXPORT_SYMBOL(io_uring_get_socket); #define io_for_each_link(pos, head) \ for (pos = (head); pos; pos = pos->link) static inline void io_clean_op(struct io_kiocb *req) { if (req->flags & (REQ_F_NEED_CLEANUP | REQ_F_BUFFER_SELECTED)) __io_clean_op(req); } static inline void io_set_resource_node(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; if (!req->fixed_rsrc_refs) { req->fixed_rsrc_refs = &ctx->file_data->node->refs; percpu_ref_get(req->fixed_rsrc_refs); } } static bool io_match_task(struct io_kiocb *head, struct task_struct *task, struct files_struct *files) { struct io_kiocb *req; if (task && head->task != task) { /* in terms of cancelation, always match if req task is dead */ if (head->task->flags & PF_EXITING) return true; return false; } if (!files) return true; io_for_each_link(req, head) { if (!(req->flags & REQ_F_WORK_INITIALIZED)) continue; if (req->file && req->file->f_op == &io_uring_fops) return true; if ((req->work.flags & IO_WQ_WORK_FILES) && req->work.identity->files == files) return true; } return false; } static void io_sq_thread_drop_mm_files(void) { struct files_struct *files = current->files; struct mm_struct *mm = current->mm; if (mm) { kthread_unuse_mm(mm); mmput(mm); current->mm = NULL; } if (files) { struct nsproxy *nsproxy = current->nsproxy; task_lock(current); current->files = NULL; current->nsproxy = NULL; task_unlock(current); put_files_struct(files); put_nsproxy(nsproxy); } } static int __io_sq_thread_acquire_files(struct io_ring_ctx *ctx) { if (!current->files) { struct files_struct *files; struct nsproxy *nsproxy; task_lock(ctx->sqo_task); files = ctx->sqo_task->files; if (!files) { task_unlock(ctx->sqo_task); return -EOWNERDEAD; } atomic_inc(&files->count); get_nsproxy(ctx->sqo_task->nsproxy); nsproxy = ctx->sqo_task->nsproxy; task_unlock(ctx->sqo_task); task_lock(current); current->files = files; current->nsproxy = nsproxy; task_unlock(current); } return 0; } static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx) { struct mm_struct *mm; if (current->mm) return 0; task_lock(ctx->sqo_task); mm = ctx->sqo_task->mm; if (unlikely(!mm || !mmget_not_zero(mm))) mm = NULL; task_unlock(ctx->sqo_task); if (mm) { kthread_use_mm(mm); return 0; } return -EFAULT; } static int __io_sq_thread_acquire_mm_files(struct io_ring_ctx *ctx, struct io_kiocb *req) { const struct io_op_def *def = &io_op_defs[req->opcode]; int ret; if (def->work_flags & IO_WQ_WORK_MM) { ret = __io_sq_thread_acquire_mm(ctx); if (unlikely(ret)) return ret; } if (def->needs_file || (def->work_flags & IO_WQ_WORK_FILES)) { ret = __io_sq_thread_acquire_files(ctx); if (unlikely(ret)) return ret; } return 0; } static inline int io_sq_thread_acquire_mm_files(struct io_ring_ctx *ctx, struct io_kiocb *req) { if (!(ctx->flags & IORING_SETUP_SQPOLL)) return 0; return __io_sq_thread_acquire_mm_files(ctx, req); } static void io_sq_thread_associate_blkcg(struct io_ring_ctx *ctx, struct cgroup_subsys_state **cur_css) { #ifdef CONFIG_BLK_CGROUP /* puts the old one when swapping */ if (*cur_css != ctx->sqo_blkcg_css) { kthread_associate_blkcg(ctx->sqo_blkcg_css); *cur_css = ctx->sqo_blkcg_css; } #endif } static void io_sq_thread_unassociate_blkcg(void) { #ifdef CONFIG_BLK_CGROUP kthread_associate_blkcg(NULL); #endif } static inline void req_set_fail_links(struct io_kiocb *req) { if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK) req->flags |= REQ_F_FAIL_LINK; } /* * None of these are dereferenced, they are simply used to check if any of * them have changed. If we're under current and check they are still the * same, we're fine to grab references to them for actual out-of-line use. */ static void io_init_identity(struct io_identity *id) { id->files = current->files; id->mm = current->mm; #ifdef CONFIG_BLK_CGROUP rcu_read_lock(); id->blkcg_css = blkcg_css(); rcu_read_unlock(); #endif id->creds = current_cred(); id->nsproxy = current->nsproxy; id->fs = current->fs; id->fsize = rlimit(RLIMIT_FSIZE); #ifdef CONFIG_AUDIT id->loginuid = current->loginuid; id->sessionid = current->sessionid; #endif refcount_set(&id->count, 1); } static inline void __io_req_init_async(struct io_kiocb *req) { memset(&req->work, 0, sizeof(req->work)); req->flags |= REQ_F_WORK_INITIALIZED; } /* * Note: must call io_req_init_async() for the first time you * touch any members of io_wq_work. */ static inline void io_req_init_async(struct io_kiocb *req) { struct io_uring_task *tctx = current->io_uring; if (req->flags & REQ_F_WORK_INITIALIZED) return; __io_req_init_async(req); /* Grab a ref if this isn't our static identity */ req->work.identity = tctx->identity; if (tctx->identity != &tctx->__identity) refcount_inc(&req->work.identity->count); } static void io_ring_ctx_ref_free(struct percpu_ref *ref) { struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs); complete(&ctx->ref_comp); } static inline bool io_is_timeout_noseq(struct io_kiocb *req) { return !req->timeout.off; } static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) { struct io_ring_ctx *ctx; int hash_bits; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return NULL; /* * Use 5 bits less than the max cq entries, that should give us around * 32 entries per hash list if totally full and uniformly spread. */ hash_bits = ilog2(p->cq_entries); hash_bits -= 5; if (hash_bits <= 0) hash_bits = 1; ctx->cancel_hash_bits = hash_bits; ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head), GFP_KERNEL); if (!ctx->cancel_hash) goto err; __hash_init(ctx->cancel_hash, 1U << hash_bits); if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free, PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) goto err; ctx->flags = p->flags; init_waitqueue_head(&ctx->sqo_sq_wait); INIT_LIST_HEAD(&ctx->sqd_list); init_waitqueue_head(&ctx->cq_wait); INIT_LIST_HEAD(&ctx->cq_overflow_list); init_completion(&ctx->ref_comp); init_completion(&ctx->sq_thread_comp); idr_init(&ctx->io_buffer_idr); idr_init(&ctx->personality_idr); mutex_init(&ctx->uring_lock); init_waitqueue_head(&ctx->wait); spin_lock_init(&ctx->completion_lock); INIT_LIST_HEAD(&ctx->iopoll_list); INIT_LIST_HEAD(&ctx->defer_list); INIT_LIST_HEAD(&ctx->timeout_list); spin_lock_init(&ctx->inflight_lock); INIT_LIST_HEAD(&ctx->inflight_list); spin_lock_init(&ctx->rsrc_ref_lock); INIT_LIST_HEAD(&ctx->rsrc_ref_list); INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work); init_llist_head(&ctx->rsrc_put_llist); INIT_LIST_HEAD(&ctx->submit_state.comp.free_list); INIT_LIST_HEAD(&ctx->submit_state.comp.locked_free_list); return ctx; err: kfree(ctx->cancel_hash); kfree(ctx); return NULL; } static bool req_need_defer(struct io_kiocb *req, u32 seq) { if (unlikely(req->flags & REQ_F_IO_DRAIN)) { struct io_ring_ctx *ctx = req->ctx; return seq != ctx->cached_cq_tail + READ_ONCE(ctx->cached_cq_overflow); } return false; } static void io_put_identity(struct io_uring_task *tctx, struct io_kiocb *req) { if (req->work.identity == &tctx->__identity) return; if (refcount_dec_and_test(&req->work.identity->count)) kfree(req->work.identity); } static void io_req_clean_work(struct io_kiocb *req) { if (!(req->flags & REQ_F_WORK_INITIALIZED)) return; if (req->work.flags & IO_WQ_WORK_MM) mmdrop(req->work.identity->mm); #ifdef CONFIG_BLK_CGROUP if (req->work.flags & IO_WQ_WORK_BLKCG) css_put(req->work.identity->blkcg_css); #endif if (req->work.flags & IO_WQ_WORK_CREDS) put_cred(req->work.identity->creds); if (req->work.flags & IO_WQ_WORK_FS) { struct fs_struct *fs = req->work.identity->fs; spin_lock(&req->work.identity->fs->lock); if (--fs->users) fs = NULL; spin_unlock(&req->work.identity->fs->lock); if (fs) free_fs_struct(fs); } if (req->work.flags & IO_WQ_WORK_FILES) { put_files_struct(req->work.identity->files); put_nsproxy(req->work.identity->nsproxy); } if (req->flags & REQ_F_INFLIGHT) { struct io_ring_ctx *ctx = req->ctx; struct io_uring_task *tctx = req->task->io_uring; unsigned long flags; spin_lock_irqsave(&ctx->inflight_lock, flags); list_del(&req->inflight_entry); spin_unlock_irqrestore(&ctx->inflight_lock, flags); req->flags &= ~REQ_F_INFLIGHT; if (atomic_read(&tctx->in_idle)) wake_up(&tctx->wait); } req->flags &= ~REQ_F_WORK_INITIALIZED; req->work.flags &= ~(IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG | IO_WQ_WORK_FS | IO_WQ_WORK_CREDS | IO_WQ_WORK_FILES); io_put_identity(req->task->io_uring, req); } /* * Create a private copy of io_identity, since some fields don't match * the current context. */ static bool io_identity_cow(struct io_kiocb *req) { struct io_uring_task *tctx = current->io_uring; const struct cred *creds = NULL; struct io_identity *id; if (req->work.flags & IO_WQ_WORK_CREDS) creds = req->work.identity->creds; id = kmemdup(req->work.identity, sizeof(*id), GFP_KERNEL); if (unlikely(!id)) { req->work.flags |= IO_WQ_WORK_CANCEL; return false; } /* * We can safely just re-init the creds we copied Either the field * matches the current one, or we haven't grabbed it yet. The only * exception is ->creds, through registered personalities, so handle * that one separately. */ io_init_identity(id); if (creds) id->creds = creds; /* add one for this request */ refcount_inc(&id->count); /* drop tctx and req identity references, if needed */ if (tctx->identity != &tctx->__identity && refcount_dec_and_test(&tctx->identity->count)) kfree(tctx->identity); if (req->work.identity != &tctx->__identity && refcount_dec_and_test(&req->work.identity->count)) kfree(req->work.identity); req->work.identity = id; tctx->identity = id; return true; } static void io_req_track_inflight(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; if (!(req->flags & REQ_F_INFLIGHT)) { io_req_init_async(req); req->flags |= REQ_F_INFLIGHT; spin_lock_irq(&ctx->inflight_lock); list_add(&req->inflight_entry, &ctx->inflight_list); spin_unlock_irq(&ctx->inflight_lock); } } static bool io_grab_identity(struct io_kiocb *req) { const struct io_op_def *def = &io_op_defs[req->opcode]; struct io_identity *id = req->work.identity; if (def->work_flags & IO_WQ_WORK_FSIZE) { if (id->fsize != rlimit(RLIMIT_FSIZE)) return false; req->work.flags |= IO_WQ_WORK_FSIZE; } #ifdef CONFIG_BLK_CGROUP if (!(req->work.flags & IO_WQ_WORK_BLKCG) && (def->work_flags & IO_WQ_WORK_BLKCG)) { rcu_read_lock(); if (id->blkcg_css != blkcg_css()) { rcu_read_unlock(); return false; } /* * This should be rare, either the cgroup is dying or the task * is moving cgroups. Just punt to root for the handful of ios. */ if (css_tryget_online(id->blkcg_css)) req->work.flags |= IO_WQ_WORK_BLKCG; rcu_read_unlock(); } #endif if (!(req->work.flags & IO_WQ_WORK_CREDS)) { if (id->creds != current_cred()) return false; get_cred(id->creds); req->work.flags |= IO_WQ_WORK_CREDS; } #ifdef CONFIG_AUDIT if (!uid_eq(current->loginuid, id->loginuid) || current->sessionid != id->sessionid) return false; #endif if (!(req->work.flags & IO_WQ_WORK_FS) && (def->work_flags & IO_WQ_WORK_FS)) { if (current->fs != id->fs) return false; spin_lock(&id->fs->lock); if (!id->fs->in_exec) { id->fs->users++; req->work.flags |= IO_WQ_WORK_FS; } else { req->work.flags |= IO_WQ_WORK_CANCEL; } spin_unlock(¤t->fs->lock); } if (!(req->work.flags & IO_WQ_WORK_FILES) && (def->work_flags & IO_WQ_WORK_FILES) && !(req->flags & REQ_F_NO_FILE_TABLE)) { if (id->files != current->files || id->nsproxy != current->nsproxy) return false; atomic_inc(&id->files->count); get_nsproxy(id->nsproxy); req->work.flags |= IO_WQ_WORK_FILES; io_req_track_inflight(req); } if (!(req->work.flags & IO_WQ_WORK_MM) && (def->work_flags & IO_WQ_WORK_MM)) { if (id->mm != current->mm) return false; mmgrab(id->mm); req->work.flags |= IO_WQ_WORK_MM; } return true; } static void io_prep_async_work(struct io_kiocb *req) { const struct io_op_def *def = &io_op_defs[req->opcode]; struct io_ring_ctx *ctx = req->ctx; io_req_init_async(req); if (req->flags & REQ_F_FORCE_ASYNC) req->work.flags |= IO_WQ_WORK_CONCURRENT; if (req->flags & REQ_F_ISREG) { if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL)) io_wq_hash_work(&req->work, file_inode(req->file)); } else { if (def->unbound_nonreg_file) req->work.flags |= IO_WQ_WORK_UNBOUND; } /* if we fail grabbing identity, we must COW, regrab, and retry */ if (io_grab_identity(req)) return; if (!io_identity_cow(req)) return; /* can't fail at this point */ if (!io_grab_identity(req)) WARN_ON(1); } static void io_prep_async_link(struct io_kiocb *req) { struct io_kiocb *cur; io_for_each_link(cur, req) io_prep_async_work(cur); } static struct io_kiocb *__io_queue_async_work(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *link = io_prep_linked_timeout(req); trace_io_uring_queue_async_work(ctx, io_wq_is_hashed(&req->work), req, &req->work, req->flags); io_wq_enqueue(ctx->io_wq, &req->work); return link; } static void io_queue_async_work(struct io_kiocb *req) { struct io_kiocb *link; /* init ->work of the whole link before punting */ io_prep_async_link(req); link = __io_queue_async_work(req); if (link) io_queue_linked_timeout(link); } static void io_kill_timeout(struct io_kiocb *req) { struct io_timeout_data *io = req->async_data; int ret; ret = hrtimer_try_to_cancel(&io->timer); if (ret != -1) { atomic_set(&req->ctx->cq_timeouts, atomic_read(&req->ctx->cq_timeouts) + 1); list_del_init(&req->timeout.list); io_cqring_fill_event(req, 0); io_put_req_deferred(req, 1); } } /* * Returns true if we found and killed one or more timeouts */ static bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk, struct files_struct *files) { struct io_kiocb *req, *tmp; int canceled = 0; spin_lock_irq(&ctx->completion_lock); list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) { if (io_match_task(req, tsk, files)) { io_kill_timeout(req); canceled++; } } spin_unlock_irq(&ctx->completion_lock); return canceled != 0; } static void __io_queue_deferred(struct io_ring_ctx *ctx) { do { struct io_defer_entry *de = list_first_entry(&ctx->defer_list, struct io_defer_entry, list); if (req_need_defer(de->req, de->seq)) break; list_del_init(&de->list); io_req_task_queue(de->req); kfree(de); } while (!list_empty(&ctx->defer_list)); } static void io_flush_timeouts(struct io_ring_ctx *ctx) { u32 seq; if (list_empty(&ctx->timeout_list)) return; seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts); do { u32 events_needed, events_got; struct io_kiocb *req = list_first_entry(&ctx->timeout_list, struct io_kiocb, timeout.list); if (io_is_timeout_noseq(req)) break; /* * Since seq can easily wrap around over time, subtract * the last seq at which timeouts were flushed before comparing. * Assuming not more than 2^31-1 events have happened since, * these subtractions won't have wrapped, so we can check if * target is in [last_seq, current_seq] by comparing the two. */ events_needed = req->timeout.target_seq - ctx->cq_last_tm_flush; events_got = seq - ctx->cq_last_tm_flush; if (events_got < events_needed) break; list_del_init(&req->timeout.list); io_kill_timeout(req); } while (!list_empty(&ctx->timeout_list)); ctx->cq_last_tm_flush = seq; } static void io_commit_cqring(struct io_ring_ctx *ctx) { io_flush_timeouts(ctx); /* order cqe stores with ring update */ smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail); if (unlikely(!list_empty(&ctx->defer_list))) __io_queue_deferred(ctx); } static inline bool io_sqring_full(struct io_ring_ctx *ctx) { struct io_rings *r = ctx->rings; return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == r->sq_ring_entries; } static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx) { return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head); } static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; unsigned tail; /* * writes to the cq entry need to come after reading head; the * control dependency is enough as we're using WRITE_ONCE to * fill the cq entry */ if (__io_cqring_events(ctx) == rings->cq_ring_entries) return NULL; tail = ctx->cached_cq_tail++; return &rings->cqes[tail & ctx->cq_mask]; } static inline bool io_should_trigger_evfd(struct io_ring_ctx *ctx) { if (!ctx->cq_ev_fd) return false; if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED) return false; if (!ctx->eventfd_async) return true; return io_wq_current_is_worker(); } static void io_cqring_ev_posted(struct io_ring_ctx *ctx) { /* see waitqueue_active() comment */ smp_mb(); if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); if (ctx->sq_data && waitqueue_active(&ctx->sq_data->wait)) wake_up(&ctx->sq_data->wait); if (io_should_trigger_evfd(ctx)) eventfd_signal(ctx->cq_ev_fd, 1); if (waitqueue_active(&ctx->cq_wait)) { wake_up_interruptible(&ctx->cq_wait); kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); } } static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx) { /* see waitqueue_active() comment */ smp_mb(); if (ctx->flags & IORING_SETUP_SQPOLL) { if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); } if (io_should_trigger_evfd(ctx)) eventfd_signal(ctx->cq_ev_fd, 1); if (waitqueue_active(&ctx->cq_wait)) { wake_up_interruptible(&ctx->cq_wait); kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); } } /* Returns true if there are no backlogged entries after the flush */ static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force, struct task_struct *tsk, struct files_struct *files) { struct io_rings *rings = ctx->rings; struct io_kiocb *req, *tmp; struct io_uring_cqe *cqe; unsigned long flags; bool all_flushed, posted; LIST_HEAD(list); if (!force && __io_cqring_events(ctx) == rings->cq_ring_entries) return false; posted = false; spin_lock_irqsave(&ctx->completion_lock, flags); list_for_each_entry_safe(req, tmp, &ctx->cq_overflow_list, compl.list) { if (!io_match_task(req, tsk, files)) continue; cqe = io_get_cqring(ctx); if (!cqe && !force) break; list_move(&req->compl.list, &list); if (cqe) { WRITE_ONCE(cqe->user_data, req->user_data); WRITE_ONCE(cqe->res, req->result); WRITE_ONCE(cqe->flags, req->compl.cflags); } else { ctx->cached_cq_overflow++; WRITE_ONCE(ctx->rings->cq_overflow, ctx->cached_cq_overflow); } posted = true; } all_flushed = list_empty(&ctx->cq_overflow_list); if (all_flushed) { clear_bit(0, &ctx->sq_check_overflow); clear_bit(0, &ctx->cq_check_overflow); ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW; } if (posted) io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); if (posted) io_cqring_ev_posted(ctx); while (!list_empty(&list)) { req = list_first_entry(&list, struct io_kiocb, compl.list); list_del(&req->compl.list); io_put_req(req); } return all_flushed; } static void io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force, struct task_struct *tsk, struct files_struct *files) { if (test_bit(0, &ctx->cq_check_overflow)) { /* iopoll syncs against uring_lock, not completion_lock */ if (ctx->flags & IORING_SETUP_IOPOLL) mutex_lock(&ctx->uring_lock); __io_cqring_overflow_flush(ctx, force, tsk, files); if (ctx->flags & IORING_SETUP_IOPOLL) mutex_unlock(&ctx->uring_lock); } } static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags) { struct io_ring_ctx *ctx = req->ctx; struct io_uring_cqe *cqe; trace_io_uring_complete(ctx, req->user_data, res); /* * If we can't get a cq entry, userspace overflowed the * submission (by quite a lot). Increment the overflow count in * the ring. */ cqe = io_get_cqring(ctx); if (likely(cqe)) { WRITE_ONCE(cqe->user_data, req->user_data); WRITE_ONCE(cqe->res, res); WRITE_ONCE(cqe->flags, cflags); } else if (ctx->cq_overflow_flushed || atomic_read(&req->task->io_uring->in_idle)) { /* * If we're in ring overflow flush mode, or in task cancel mode, * then we cannot store the request for later flushing, we need * to drop it on the floor. */ ctx->cached_cq_overflow++; WRITE_ONCE(ctx->rings->cq_overflow, ctx->cached_cq_overflow); } else { if (list_empty(&ctx->cq_overflow_list)) { set_bit(0, &ctx->sq_check_overflow); set_bit(0, &ctx->cq_check_overflow); ctx->rings->sq_flags |= IORING_SQ_CQ_OVERFLOW; } io_clean_op(req); req->result = res; req->compl.cflags = cflags; refcount_inc(&req->refs); list_add_tail(&req->compl.list, &ctx->cq_overflow_list); } } static void io_cqring_fill_event(struct io_kiocb *req, long res) { __io_cqring_fill_event(req, res, 0); } static inline void io_req_complete_post(struct io_kiocb *req, long res, unsigned int cflags) { struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); __io_cqring_fill_event(req, res, cflags); io_commit_cqring(ctx); /* * If we're the last reference to this request, add to our locked * free_list cache. */ if (refcount_dec_and_test(&req->refs)) { struct io_comp_state *cs = &ctx->submit_state.comp; io_dismantle_req(req); io_put_task(req->task, 1); list_add(&req->compl.list, &cs->locked_free_list); cs->locked_free_nr++; } else req = NULL; spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); if (req) { io_queue_next(req); percpu_ref_put(&ctx->refs); } } static void io_req_complete_state(struct io_kiocb *req, long res, unsigned int cflags) { io_clean_op(req); req->result = res; req->compl.cflags = cflags; req->flags |= REQ_F_COMPLETE_INLINE; } static inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags, long res, unsigned cflags) { if (issue_flags & IO_URING_F_COMPLETE_DEFER) io_req_complete_state(req, res, cflags); else io_req_complete_post(req, res, cflags); } static inline void io_req_complete(struct io_kiocb *req, long res) { __io_req_complete(req, 0, res, 0); } static bool io_flush_cached_reqs(struct io_ring_ctx *ctx) { struct io_submit_state *state = &ctx->submit_state; struct io_comp_state *cs = &state->comp; struct io_kiocb *req = NULL; /* * If we have more than a batch's worth of requests in our IRQ side * locked cache, grab the lock and move them over to our submission * side cache. */ if (READ_ONCE(cs->locked_free_nr) > IO_COMPL_BATCH) { spin_lock_irq(&ctx->completion_lock); list_splice_init(&cs->locked_free_list, &cs->free_list); cs->locked_free_nr = 0; spin_unlock_irq(&ctx->completion_lock); } while (!list_empty(&cs->free_list)) { req = list_first_entry(&cs->free_list, struct io_kiocb, compl.list); list_del(&req->compl.list); state->reqs[state->free_reqs++] = req; if (state->free_reqs == ARRAY_SIZE(state->reqs)) break; } return req != NULL; } static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx) { struct io_submit_state *state = &ctx->submit_state; BUILD_BUG_ON(IO_REQ_ALLOC_BATCH > ARRAY_SIZE(state->reqs)); if (!state->free_reqs) { gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; int ret; if (io_flush_cached_reqs(ctx)) goto got_req; ret = kmem_cache_alloc_bulk(req_cachep, gfp, IO_REQ_ALLOC_BATCH, state->reqs); /* * Bulk alloc is all-or-nothing. If we fail to get a batch, * retry single alloc to be on the safe side. */ if (unlikely(ret <= 0)) { state->reqs[0] = kmem_cache_alloc(req_cachep, gfp); if (!state->reqs[0]) return NULL; ret = 1; } state->free_reqs = ret; } got_req: state->free_reqs--; return state->reqs[state->free_reqs]; } static inline void io_put_file(struct io_kiocb *req, struct file *file, bool fixed) { if (!fixed) fput(file); } static void io_dismantle_req(struct io_kiocb *req) { io_clean_op(req); if (req->async_data) kfree(req->async_data); if (req->file) io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE)); if (req->fixed_rsrc_refs) percpu_ref_put(req->fixed_rsrc_refs); io_req_clean_work(req); } static inline void io_put_task(struct task_struct *task, int nr) { struct io_uring_task *tctx = task->io_uring; percpu_counter_sub(&tctx->inflight, nr); if (unlikely(atomic_read(&tctx->in_idle))) wake_up(&tctx->wait); put_task_struct_many(task, nr); } static void __io_free_req(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; io_dismantle_req(req); io_put_task(req->task, 1); kmem_cache_free(req_cachep, req); percpu_ref_put(&ctx->refs); } static inline void io_remove_next_linked(struct io_kiocb *req) { struct io_kiocb *nxt = req->link; req->link = nxt->link; nxt->link = NULL; } static void io_kill_linked_timeout(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *link; bool cancelled = false; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); link = req->link; /* * Can happen if a linked timeout fired and link had been like * req -> link t-out -> link t-out [-> ...] */ if (link && (link->flags & REQ_F_LTIMEOUT_ACTIVE)) { struct io_timeout_data *io = link->async_data; int ret; io_remove_next_linked(req); link->timeout.head = NULL; ret = hrtimer_try_to_cancel(&io->timer); if (ret != -1) { io_cqring_fill_event(link, -ECANCELED); io_commit_cqring(ctx); cancelled = true; } } req->flags &= ~REQ_F_LINK_TIMEOUT; spin_unlock_irqrestore(&ctx->completion_lock, flags); if (cancelled) { io_cqring_ev_posted(ctx); io_put_req(link); } } static void io_fail_links(struct io_kiocb *req) { struct io_kiocb *link, *nxt; struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); link = req->link; req->link = NULL; while (link) { nxt = link->link; link->link = NULL; trace_io_uring_fail_link(req, link); io_cqring_fill_event(link, -ECANCELED); /* * It's ok to free under spinlock as they're not linked anymore, * but avoid REQ_F_WORK_INITIALIZED because it may deadlock on * work.fs->lock. */ if (link->flags & REQ_F_WORK_INITIALIZED) io_put_req_deferred(link, 2); else io_double_put_req(link); link = nxt; } io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); } static struct io_kiocb *__io_req_find_next(struct io_kiocb *req) { if (req->flags & REQ_F_LINK_TIMEOUT) io_kill_linked_timeout(req); /* * If LINK is set, we have dependent requests in this chain. If we * didn't fail this request, queue the first one up, moving any other * dependencies to the next request. In case of failure, fail the rest * of the chain. */ if (likely(!(req->flags & REQ_F_FAIL_LINK))) { struct io_kiocb *nxt = req->link; req->link = NULL; return nxt; } io_fail_links(req); return NULL; } static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req) { if (likely(!(req->flags & (REQ_F_LINK|REQ_F_HARDLINK)))) return NULL; return __io_req_find_next(req); } static bool __tctx_task_work(struct io_uring_task *tctx) { struct io_ring_ctx *ctx = NULL; struct io_wq_work_list list; struct io_wq_work_node *node; if (wq_list_empty(&tctx->task_list)) return false; spin_lock_irq(&tctx->task_lock); list = tctx->task_list; INIT_WQ_LIST(&tctx->task_list); spin_unlock_irq(&tctx->task_lock); node = list.first; while (node) { struct io_wq_work_node *next = node->next; struct io_ring_ctx *this_ctx; struct io_kiocb *req; req = container_of(node, struct io_kiocb, io_task_work.node); this_ctx = req->ctx; req->task_work.func(&req->task_work); node = next; if (!ctx) { ctx = this_ctx; } else if (ctx != this_ctx) { mutex_lock(&ctx->uring_lock); io_submit_flush_completions(&ctx->submit_state.comp, ctx); mutex_unlock(&ctx->uring_lock); ctx = this_ctx; } } if (ctx && ctx->submit_state.comp.nr) { mutex_lock(&ctx->uring_lock); io_submit_flush_completions(&ctx->submit_state.comp, ctx); mutex_unlock(&ctx->uring_lock); } return list.first != NULL; } static void tctx_task_work(struct callback_head *cb) { struct io_uring_task *tctx = container_of(cb, struct io_uring_task, task_work); while (__tctx_task_work(tctx)) cond_resched(); clear_bit(0, &tctx->task_state); } static int io_task_work_add(struct task_struct *tsk, struct io_kiocb *req, enum task_work_notify_mode notify) { struct io_uring_task *tctx = tsk->io_uring; struct io_wq_work_node *node, *prev; unsigned long flags; int ret; WARN_ON_ONCE(!tctx); spin_lock_irqsave(&tctx->task_lock, flags); wq_list_add_tail(&req->io_task_work.node, &tctx->task_list); spin_unlock_irqrestore(&tctx->task_lock, flags); /* task_work already pending, we're done */ if (test_bit(0, &tctx->task_state) || test_and_set_bit(0, &tctx->task_state)) return 0; if (!task_work_add(tsk, &tctx->task_work, notify)) return 0; /* * Slow path - we failed, find and delete work. if the work is not * in the list, it got run and we're fine. */ ret = 0; spin_lock_irqsave(&tctx->task_lock, flags); wq_list_for_each(node, prev, &tctx->task_list) { if (&req->io_task_work.node == node) { wq_list_del(&tctx->task_list, node, prev); ret = 1; break; } } spin_unlock_irqrestore(&tctx->task_lock, flags); clear_bit(0, &tctx->task_state); return ret; } static int io_req_task_work_add(struct io_kiocb *req) { struct task_struct *tsk = req->task; struct io_ring_ctx *ctx = req->ctx; enum task_work_notify_mode notify; int ret; if (tsk->flags & PF_EXITING) return -ESRCH; /* * SQPOLL kernel thread doesn't need notification, just a wakeup. For * all other cases, use TWA_SIGNAL unconditionally to ensure we're * processing task_work. There's no reliable way to tell if TWA_RESUME * will do the job. */ notify = TWA_NONE; if (!(ctx->flags & IORING_SETUP_SQPOLL)) notify = TWA_SIGNAL; ret = io_task_work_add(tsk, req, notify); if (!ret) wake_up_process(tsk); return ret; } static void io_req_task_work_add_fallback(struct io_kiocb *req, task_work_func_t cb) { struct task_struct *tsk = io_wq_get_task(req->ctx->io_wq); init_task_work(&req->task_work, cb); task_work_add(tsk, &req->task_work, TWA_NONE); wake_up_process(tsk); } static void __io_req_task_cancel(struct io_kiocb *req, int error) { struct io_ring_ctx *ctx = req->ctx; spin_lock_irq(&ctx->completion_lock); io_cqring_fill_event(req, error); io_commit_cqring(ctx); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); req_set_fail_links(req); io_double_put_req(req); } static void io_req_task_cancel(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); struct io_ring_ctx *ctx = req->ctx; __io_req_task_cancel(req, -ECANCELED); percpu_ref_put(&ctx->refs); } static void __io_req_task_submit(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; /* ctx stays valid until unlock, even if we drop all ours ctx->refs */ mutex_lock(&ctx->uring_lock); if (!ctx->sqo_dead && !(current->flags & PF_EXITING) && !io_sq_thread_acquire_mm_files(ctx, req)) __io_queue_sqe(req); else __io_req_task_cancel(req, -EFAULT); mutex_unlock(&ctx->uring_lock); } static void io_req_task_submit(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); __io_req_task_submit(req); } static void io_req_task_queue(struct io_kiocb *req) { int ret; req->task_work.func = io_req_task_submit; ret = io_req_task_work_add(req); if (unlikely(ret)) { percpu_ref_get(&req->ctx->refs); io_req_task_work_add_fallback(req, io_req_task_cancel); } } static inline void io_queue_next(struct io_kiocb *req) { struct io_kiocb *nxt = io_req_find_next(req); if (nxt) io_req_task_queue(nxt); } static void io_free_req(struct io_kiocb *req) { io_queue_next(req); __io_free_req(req); } struct req_batch { struct task_struct *task; int task_refs; int ctx_refs; }; static inline void io_init_req_batch(struct req_batch *rb) { rb->task_refs = 0; rb->ctx_refs = 0; rb->task = NULL; } static void io_req_free_batch_finish(struct io_ring_ctx *ctx, struct req_batch *rb) { if (rb->task) io_put_task(rb->task, rb->task_refs); if (rb->ctx_refs) percpu_ref_put_many(&ctx->refs, rb->ctx_refs); } static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req, struct io_submit_state *state) { io_queue_next(req); if (req->task != rb->task) { if (rb->task) io_put_task(rb->task, rb->task_refs); rb->task = req->task; rb->task_refs = 0; } rb->task_refs++; rb->ctx_refs++; io_dismantle_req(req); if (state->free_reqs != ARRAY_SIZE(state->reqs)) state->reqs[state->free_reqs++] = req; else list_add(&req->compl.list, &state->comp.free_list); } static void io_submit_flush_completions(struct io_comp_state *cs, struct io_ring_ctx *ctx) { int i, nr = cs->nr; struct io_kiocb *req; struct req_batch rb; io_init_req_batch(&rb); spin_lock_irq(&ctx->completion_lock); for (i = 0; i < nr; i++) { req = cs->reqs[i]; __io_cqring_fill_event(req, req->result, req->compl.cflags); } io_commit_cqring(ctx); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); for (i = 0; i < nr; i++) { req = cs->reqs[i]; /* submission and completion refs */ if (refcount_sub_and_test(2, &req->refs)) io_req_free_batch(&rb, req, &ctx->submit_state); } io_req_free_batch_finish(ctx, &rb); cs->nr = 0; } /* * Drop reference to request, return next in chain (if there is one) if this * was the last reference to this request. */ static struct io_kiocb *io_put_req_find_next(struct io_kiocb *req) { struct io_kiocb *nxt = NULL; if (refcount_dec_and_test(&req->refs)) { nxt = io_req_find_next(req); __io_free_req(req); } return nxt; } static void io_put_req(struct io_kiocb *req) { if (refcount_dec_and_test(&req->refs)) io_free_req(req); } static void io_put_req_deferred_cb(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); io_free_req(req); } static void io_free_req_deferred(struct io_kiocb *req) { int ret; req->task_work.func = io_put_req_deferred_cb; ret = io_req_task_work_add(req); if (unlikely(ret)) io_req_task_work_add_fallback(req, io_put_req_deferred_cb); } static inline void io_put_req_deferred(struct io_kiocb *req, int refs) { if (refcount_sub_and_test(refs, &req->refs)) io_free_req_deferred(req); } static void io_double_put_req(struct io_kiocb *req) { /* drop both submit and complete references */ if (refcount_sub_and_test(2, &req->refs)) io_free_req(req); } static unsigned io_cqring_events(struct io_ring_ctx *ctx) { /* See comment at the top of this file */ smp_rmb(); return __io_cqring_events(ctx); } static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; /* make sure SQ entry isn't read before tail */ return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head; } static unsigned int io_put_kbuf(struct io_kiocb *req, struct io_buffer *kbuf) { unsigned int cflags; cflags = kbuf->bid << IORING_CQE_BUFFER_SHIFT; cflags |= IORING_CQE_F_BUFFER; req->flags &= ~REQ_F_BUFFER_SELECTED; kfree(kbuf); return cflags; } static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req) { struct io_buffer *kbuf; kbuf = (struct io_buffer *) (unsigned long) req->rw.addr; return io_put_kbuf(req, kbuf); } static inline bool io_run_task_work(void) { /* * Not safe to run on exiting task, and the task_work handling will * not add work to such a task. */ if (unlikely(current->flags & PF_EXITING)) return false; if (current->task_works) { __set_current_state(TASK_RUNNING); task_work_run(); return true; } return false; } /* * Find and free completed poll iocbs */ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, struct list_head *done) { struct req_batch rb; struct io_kiocb *req; /* order with ->result store in io_complete_rw_iopoll() */ smp_rmb(); io_init_req_batch(&rb); while (!list_empty(done)) { int cflags = 0; req = list_first_entry(done, struct io_kiocb, inflight_entry); list_del(&req->inflight_entry); if (READ_ONCE(req->result) == -EAGAIN) { req->iopoll_completed = 0; if (io_rw_reissue(req)) continue; } if (req->flags & REQ_F_BUFFER_SELECTED) cflags = io_put_rw_kbuf(req); __io_cqring_fill_event(req, req->result, cflags); (*nr_events)++; if (refcount_dec_and_test(&req->refs)) io_req_free_batch(&rb, req, &ctx->submit_state); } io_commit_cqring(ctx); io_cqring_ev_posted_iopoll(ctx); io_req_free_batch_finish(ctx, &rb); } static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, long min) { struct io_kiocb *req, *tmp; LIST_HEAD(done); bool spin; int ret; /* * Only spin for completions if we don't have multiple devices hanging * off our complete list, and we're under the requested amount. */ spin = !ctx->poll_multi_file && *nr_events < min; ret = 0; list_for_each_entry_safe(req, tmp, &ctx->iopoll_list, inflight_entry) { struct kiocb *kiocb = &req->rw.kiocb; /* * Move completed and retryable entries to our local lists. * If we find a request that requires polling, break out * and complete those lists first, if we have entries there. */ if (READ_ONCE(req->iopoll_completed)) { list_move_tail(&req->inflight_entry, &done); continue; } if (!list_empty(&done)) break; ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin); if (ret < 0) break; /* iopoll may have completed current req */ if (READ_ONCE(req->iopoll_completed)) list_move_tail(&req->inflight_entry, &done); if (ret && spin) spin = false; ret = 0; } if (!list_empty(&done)) io_iopoll_complete(ctx, nr_events, &done); return ret; } /* * Poll for a minimum of 'min' events. Note that if min == 0 we consider that a * non-spinning poll check - we'll still enter the driver poll loop, but only * as a non-spinning completion check. */ static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events, long min) { while (!list_empty(&ctx->iopoll_list) && !need_resched()) { int ret; ret = io_do_iopoll(ctx, nr_events, min); if (ret < 0) return ret; if (*nr_events >= min) return 0; } return 1; } /* * We can't just wait for polled events to come to us, we have to actively * find and complete them. */ static void io_iopoll_try_reap_events(struct io_ring_ctx *ctx) { if (!(ctx->flags & IORING_SETUP_IOPOLL)) return; mutex_lock(&ctx->uring_lock); while (!list_empty(&ctx->iopoll_list)) { unsigned int nr_events = 0; io_do_iopoll(ctx, &nr_events, 0); /* let it sleep and repeat later if can't complete a request */ if (nr_events == 0) break; /* * Ensure we allow local-to-the-cpu processing to take place, * in this case we need to ensure that we reap all events. * Also let task_work, etc. to progress by releasing the mutex */ if (need_resched()) { mutex_unlock(&ctx->uring_lock); cond_resched(); mutex_lock(&ctx->uring_lock); } } mutex_unlock(&ctx->uring_lock); } static int io_iopoll_check(struct io_ring_ctx *ctx, long min) { unsigned int nr_events = 0; int iters = 0, ret = 0; /* * We disallow the app entering submit/complete with polling, but we * still need to lock the ring to prevent racing with polled issue * that got punted to a workqueue. */ mutex_lock(&ctx->uring_lock); do { /* * Don't enter poll loop if we already have events pending. * If we do, we can potentially be spinning for commands that * already triggered a CQE (eg in error). */ if (test_bit(0, &ctx->cq_check_overflow)) __io_cqring_overflow_flush(ctx, false, NULL, NULL); if (io_cqring_events(ctx)) break; /* * If a submit got punted to a workqueue, we can have the * application entering polling for a command before it gets * issued. That app will hold the uring_lock for the duration * of the poll right here, so we need to take a breather every * now and then to ensure that the issue has a chance to add * the poll to the issued list. Otherwise we can spin here * forever, while the workqueue is stuck trying to acquire the * very same mutex. */ if (!(++iters & 7)) { mutex_unlock(&ctx->uring_lock); io_run_task_work(); mutex_lock(&ctx->uring_lock); } ret = io_iopoll_getevents(ctx, &nr_events, min); if (ret <= 0) break; ret = 0; } while (min && !nr_events && !need_resched()); mutex_unlock(&ctx->uring_lock); return ret; } static void kiocb_end_write(struct io_kiocb *req) { /* * Tell lockdep we inherited freeze protection from submission * thread. */ if (req->flags & REQ_F_ISREG) { struct inode *inode = file_inode(req->file); __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE); } file_end_write(req->file); } #ifdef CONFIG_BLOCK static bool io_resubmit_prep(struct io_kiocb *req) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; int rw, ret; struct iov_iter iter; /* already prepared */ if (req->async_data) return true; switch (req->opcode) { case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: rw = READ; break; case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: rw = WRITE; break; default: printk_once(KERN_WARNING "io_uring: bad opcode in resubmit %d\n", req->opcode); return false; } ret = io_import_iovec(rw, req, &iovec, &iter, false); if (ret < 0) return false; return !io_setup_async_rw(req, iovec, inline_vecs, &iter, false); } #endif static bool io_rw_reissue(struct io_kiocb *req) { #ifdef CONFIG_BLOCK umode_t mode = file_inode(req->file)->i_mode; int ret; if (!S_ISBLK(mode) && !S_ISREG(mode)) return false; if ((req->flags & REQ_F_NOWAIT) || io_wq_current_is_worker()) return false; lockdep_assert_held(&req->ctx->uring_lock); ret = io_sq_thread_acquire_mm_files(req->ctx, req); if (!ret && io_resubmit_prep(req)) { refcount_inc(&req->refs); io_queue_async_work(req); return true; } req_set_fail_links(req); #endif return false; } static void __io_complete_rw(struct io_kiocb *req, long res, long res2, unsigned int issue_flags) { int cflags = 0; if ((res == -EAGAIN || res == -EOPNOTSUPP) && io_rw_reissue(req)) return; if (res != req->result) req_set_fail_links(req); if (req->rw.kiocb.ki_flags & IOCB_WRITE) kiocb_end_write(req); if (req->flags & REQ_F_BUFFER_SELECTED) cflags = io_put_rw_kbuf(req); __io_req_complete(req, issue_flags, res, cflags); } static void io_complete_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); __io_complete_rw(req, res, res2, 0); } static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); if (kiocb->ki_flags & IOCB_WRITE) kiocb_end_write(req); if (res != -EAGAIN && res != req->result) req_set_fail_links(req); WRITE_ONCE(req->result, res); /* order with io_poll_complete() checking ->result */ smp_wmb(); WRITE_ONCE(req->iopoll_completed, 1); } /* * After the iocb has been issued, it's safe to be found on the poll list. * Adding the kiocb to the list AFTER submission ensures that we don't * find it from a io_iopoll_getevents() thread before the issuer is done * accessing the kiocb cookie. */ static void io_iopoll_req_issued(struct io_kiocb *req, bool in_async) { struct io_ring_ctx *ctx = req->ctx; /* * Track whether we have multiple files in our lists. This will impact * how we do polling eventually, not spinning if we're on potentially * different devices. */ if (list_empty(&ctx->iopoll_list)) { ctx->poll_multi_file = false; } else if (!ctx->poll_multi_file) { struct io_kiocb *list_req; list_req = list_first_entry(&ctx->iopoll_list, struct io_kiocb, inflight_entry); if (list_req->file != req->file) ctx->poll_multi_file = true; } /* * For fast devices, IO may have already completed. If it has, add * it to the front so we find it first. */ if (READ_ONCE(req->iopoll_completed)) list_add(&req->inflight_entry, &ctx->iopoll_list); else list_add_tail(&req->inflight_entry, &ctx->iopoll_list); /* * If IORING_SETUP_SQPOLL is enabled, sqes are either handled in sq thread * task context or in io worker task context. If current task context is * sq thread, we don't need to check whether should wake up sq thread. */ if (in_async && (ctx->flags & IORING_SETUP_SQPOLL) && wq_has_sleeper(&ctx->sq_data->wait)) wake_up(&ctx->sq_data->wait); } static inline void io_state_file_put(struct io_submit_state *state) { if (state->file_refs) { fput_many(state->file, state->file_refs); state->file_refs = 0; } } /* * Get as many references to a file as we have IOs left in this submission, * assuming most submissions are for one file, or at least that each file * has more than one submission. */ static struct file *__io_file_get(struct io_submit_state *state, int fd) { if (!state) return fget(fd); if (state->file_refs) { if (state->fd == fd) { state->file_refs--; return state->file; } io_state_file_put(state); } state->file = fget_many(fd, state->ios_left); if (unlikely(!state->file)) return NULL; state->fd = fd; state->file_refs = state->ios_left - 1; return state->file; } static bool io_bdev_nowait(struct block_device *bdev) { return !bdev || blk_queue_nowait(bdev_get_queue(bdev)); } /* * If we tracked the file through the SCM inflight mechanism, we could support * any file. For now, just ensure that anything potentially problematic is done * inline. */ static bool io_file_supports_async(struct file *file, int rw) { umode_t mode = file_inode(file)->i_mode; if (S_ISBLK(mode)) { if (IS_ENABLED(CONFIG_BLOCK) && io_bdev_nowait(I_BDEV(file->f_mapping->host))) return true; return false; } if (S_ISCHR(mode) || S_ISSOCK(mode)) return true; if (S_ISREG(mode)) { if (IS_ENABLED(CONFIG_BLOCK) && io_bdev_nowait(file->f_inode->i_sb->s_bdev) && file->f_op != &io_uring_fops) return true; return false; } /* any ->read/write should understand O_NONBLOCK */ if (file->f_flags & O_NONBLOCK) return true; if (!(file->f_mode & FMODE_NOWAIT)) return false; if (rw == READ) return file->f_op->read_iter != NULL; return file->f_op->write_iter != NULL; } static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw.kiocb; struct file *file = req->file; unsigned ioprio; int ret; if (S_ISREG(file_inode(file)->i_mode)) req->flags |= REQ_F_ISREG; kiocb->ki_pos = READ_ONCE(sqe->off); if (kiocb->ki_pos == -1 && !(file->f_mode & FMODE_STREAM)) { req->flags |= REQ_F_CUR_POS; kiocb->ki_pos = file->f_pos; } kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp)); kiocb->ki_flags = iocb_flags(kiocb->ki_filp); ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags)); if (unlikely(ret)) return ret; /* don't allow async punt for O_NONBLOCK or RWF_NOWAIT */ if ((kiocb->ki_flags & IOCB_NOWAIT) || (file->f_flags & O_NONBLOCK)) req->flags |= REQ_F_NOWAIT; ioprio = READ_ONCE(sqe->ioprio); if (ioprio) { ret = ioprio_check_cap(ioprio); if (ret) return ret; kiocb->ki_ioprio = ioprio; } else kiocb->ki_ioprio = get_current_ioprio(); if (ctx->flags & IORING_SETUP_IOPOLL) { if (!(kiocb->ki_flags & IOCB_DIRECT) || !kiocb->ki_filp->f_op->iopoll) return -EOPNOTSUPP; kiocb->ki_flags |= IOCB_HIPRI; kiocb->ki_complete = io_complete_rw_iopoll; req->iopoll_completed = 0; } else { if (kiocb->ki_flags & IOCB_HIPRI) return -EINVAL; kiocb->ki_complete = io_complete_rw; } req->rw.addr = READ_ONCE(sqe->addr); req->rw.len = READ_ONCE(sqe->len); req->buf_index = READ_ONCE(sqe->buf_index); return 0; } static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) { switch (ret) { case -EIOCBQUEUED: break; case -ERESTARTSYS: case -ERESTARTNOINTR: case -ERESTARTNOHAND: case -ERESTART_RESTARTBLOCK: /* * We can't just restart the syscall, since previously * submitted sqes may already be in progress. Just fail this * IO with EINTR. */ ret = -EINTR; fallthrough; default: kiocb->ki_complete(kiocb, ret, 0); } } static void kiocb_done(struct kiocb *kiocb, ssize_t ret, unsigned int issue_flags) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); struct io_async_rw *io = req->async_data; /* add previously done IO, if any */ if (io && io->bytes_done > 0) { if (ret < 0) ret = io->bytes_done; else ret += io->bytes_done; } if (req->flags & REQ_F_CUR_POS) req->file->f_pos = kiocb->ki_pos; if (ret >= 0 && kiocb->ki_complete == io_complete_rw) __io_complete_rw(req, ret, 0, issue_flags); else io_rw_done(kiocb, ret); } static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter) { struct io_ring_ctx *ctx = req->ctx; size_t len = req->rw.len; struct io_mapped_ubuf *imu; u16 index, buf_index = req->buf_index; size_t offset; u64 buf_addr; if (unlikely(buf_index >= ctx->nr_user_bufs)) return -EFAULT; index = array_index_nospec(buf_index, ctx->nr_user_bufs); imu = &ctx->user_bufs[index]; buf_addr = req->rw.addr; /* overflow */ if (buf_addr + len < buf_addr) return -EFAULT; /* not inside the mapped region */ if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len) return -EFAULT; /* * May not be a start of buffer, set size appropriately * and advance us to the beginning. */ offset = buf_addr - imu->ubuf; iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); if (offset) { /* * Don't use iov_iter_advance() here, as it's really slow for * using the latter parts of a big fixed buffer - it iterates * over each segment manually. We can cheat a bit here, because * we know that: * * 1) it's a BVEC iter, we set it up * 2) all bvecs are PAGE_SIZE in size, except potentially the * first and last bvec * * So just find our index, and adjust the iterator afterwards. * If the offset is within the first bvec (or the whole first * bvec, just use iov_iter_advance(). This makes it easier * since we can just skip the first segment, which may not * be PAGE_SIZE aligned. */ const struct bio_vec *bvec = imu->bvec; if (offset <= bvec->bv_len) { iov_iter_advance(iter, offset); } else { unsigned long seg_skip; /* skip first vec */ offset -= bvec->bv_len; seg_skip = 1 + (offset >> PAGE_SHIFT); iter->bvec = bvec + seg_skip; iter->nr_segs -= seg_skip; iter->count -= bvec->bv_len + offset; iter->iov_offset = offset & ~PAGE_MASK; } } return 0; } static void io_ring_submit_unlock(struct io_ring_ctx *ctx, bool needs_lock) { if (needs_lock) mutex_unlock(&ctx->uring_lock); } static void io_ring_submit_lock(struct io_ring_ctx *ctx, bool needs_lock) { /* * "Normal" inline submissions always hold the uring_lock, since we * grab it from the system call. Same is true for the SQPOLL offload. * The only exception is when we've detached the request and issue it * from an async worker thread, grab the lock for that case. */ if (needs_lock) mutex_lock(&ctx->uring_lock); } static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len, int bgid, struct io_buffer *kbuf, bool needs_lock) { struct io_buffer *head; if (req->flags & REQ_F_BUFFER_SELECTED) return kbuf; io_ring_submit_lock(req->ctx, needs_lock); lockdep_assert_held(&req->ctx->uring_lock); head = idr_find(&req->ctx->io_buffer_idr, bgid); if (head) { if (!list_empty(&head->list)) { kbuf = list_last_entry(&head->list, struct io_buffer, list); list_del(&kbuf->list); } else { kbuf = head; idr_remove(&req->ctx->io_buffer_idr, bgid); } if (*len > kbuf->len) *len = kbuf->len; } else { kbuf = ERR_PTR(-ENOBUFS); } io_ring_submit_unlock(req->ctx, needs_lock); return kbuf; } static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len, bool needs_lock) { struct io_buffer *kbuf; u16 bgid; kbuf = (struct io_buffer *) (unsigned long) req->rw.addr; bgid = req->buf_index; kbuf = io_buffer_select(req, len, bgid, kbuf, needs_lock); if (IS_ERR(kbuf)) return kbuf; req->rw.addr = (u64) (unsigned long) kbuf; req->flags |= REQ_F_BUFFER_SELECTED; return u64_to_user_ptr(kbuf->addr); } #ifdef CONFIG_COMPAT static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov, bool needs_lock) { struct compat_iovec __user *uiov; compat_ssize_t clen; void __user *buf; ssize_t len; uiov = u64_to_user_ptr(req->rw.addr); if (!access_ok(uiov, sizeof(*uiov))) return -EFAULT; if (__get_user(clen, &uiov->iov_len)) return -EFAULT; if (clen < 0) return -EINVAL; len = clen; buf = io_rw_buffer_select(req, &len, needs_lock); if (IS_ERR(buf)) return PTR_ERR(buf); iov[0].iov_base = buf; iov[0].iov_len = (compat_size_t) len; return 0; } #endif static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, bool needs_lock) { struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr); void __user *buf; ssize_t len; if (copy_from_user(iov, uiov, sizeof(*uiov))) return -EFAULT; len = iov[0].iov_len; if (len < 0) return -EINVAL; buf = io_rw_buffer_select(req, &len, needs_lock); if (IS_ERR(buf)) return PTR_ERR(buf); iov[0].iov_base = buf; iov[0].iov_len = len; return 0; } static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, bool needs_lock) { if (req->flags & REQ_F_BUFFER_SELECTED) { struct io_buffer *kbuf; kbuf = (struct io_buffer *) (unsigned long) req->rw.addr; iov[0].iov_base = u64_to_user_ptr(kbuf->addr); iov[0].iov_len = kbuf->len; return 0; } if (req->rw.len != 1) return -EINVAL; #ifdef CONFIG_COMPAT if (req->ctx->compat) return io_compat_import(req, iov, needs_lock); #endif return __io_iov_buffer_select(req, iov, needs_lock); } static int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, struct iov_iter *iter, bool needs_lock) { void __user *buf = u64_to_user_ptr(req->rw.addr); size_t sqe_len = req->rw.len; u8 opcode = req->opcode; ssize_t ret; if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) { *iovec = NULL; return io_import_fixed(req, rw, iter); } /* buffer index only valid with fixed read/write, or buffer select */ if (req->buf_index && !(req->flags & REQ_F_BUFFER_SELECT)) return -EINVAL; if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) { if (req->flags & REQ_F_BUFFER_SELECT) { buf = io_rw_buffer_select(req, &sqe_len, needs_lock); if (IS_ERR(buf)) return PTR_ERR(buf); req->rw.len = sqe_len; } ret = import_single_range(rw, buf, sqe_len, *iovec, iter); *iovec = NULL; return ret; } if (req->flags & REQ_F_BUFFER_SELECT) { ret = io_iov_buffer_select(req, *iovec, needs_lock); if (!ret) iov_iter_init(iter, rw, *iovec, 1, (*iovec)->iov_len); *iovec = NULL; return ret; } return __import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter, req->ctx->compat); } static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb) { return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos; } /* * For files that don't have ->read_iter() and ->write_iter(), handle them * by looping over ->read() or ->write() manually. */ static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter) { struct kiocb *kiocb = &req->rw.kiocb; struct file *file = req->file; ssize_t ret = 0; /* * Don't support polled IO through this interface, and we can't * support non-blocking either. For the latter, this just causes * the kiocb to be handled from an async context. */ if (kiocb->ki_flags & IOCB_HIPRI) return -EOPNOTSUPP; if (kiocb->ki_flags & IOCB_NOWAIT) return -EAGAIN; while (iov_iter_count(iter)) { struct iovec iovec; ssize_t nr; if (!iov_iter_is_bvec(iter)) { iovec = iov_iter_iovec(iter); } else { iovec.iov_base = u64_to_user_ptr(req->rw.addr); iovec.iov_len = req->rw.len; } if (rw == READ) { nr = file->f_op->read(file, iovec.iov_base, iovec.iov_len, io_kiocb_ppos(kiocb)); } else { nr = file->f_op->write(file, iovec.iov_base, iovec.iov_len, io_kiocb_ppos(kiocb)); } if (nr < 0) { if (!ret) ret = nr; break; } ret += nr; if (nr != iovec.iov_len) break; req->rw.len -= nr; req->rw.addr += nr; iov_iter_advance(iter, nr); } return ret; } static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec, const struct iovec *fast_iov, struct iov_iter *iter) { struct io_async_rw *rw = req->async_data; memcpy(&rw->iter, iter, sizeof(*iter)); rw->free_iovec = iovec; rw->bytes_done = 0; /* can only be fixed buffers, no need to do anything */ if (iov_iter_is_bvec(iter)) return; if (!iovec) { unsigned iov_off = 0; rw->iter.iov = rw->fast_iov; if (iter->iov != fast_iov) { iov_off = iter->iov - fast_iov; rw->iter.iov += iov_off; } if (rw->fast_iov != fast_iov) memcpy(rw->fast_iov + iov_off, fast_iov + iov_off, sizeof(struct iovec) * iter->nr_segs); } else { req->flags |= REQ_F_NEED_CLEANUP; } } static inline int __io_alloc_async_data(struct io_kiocb *req) { WARN_ON_ONCE(!io_op_defs[req->opcode].async_size); req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL); return req->async_data == NULL; } static int io_alloc_async_data(struct io_kiocb *req) { if (!io_op_defs[req->opcode].needs_async_data) return 0; return __io_alloc_async_data(req); } static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec, const struct iovec *fast_iov, struct iov_iter *iter, bool force) { if (!force && !io_op_defs[req->opcode].needs_async_data) return 0; if (!req->async_data) { if (__io_alloc_async_data(req)) { kfree(iovec); return -ENOMEM; } io_req_map_rw(req, iovec, fast_iov, iter); } return 0; } static inline int io_rw_prep_async(struct io_kiocb *req, int rw) { struct io_async_rw *iorw = req->async_data; struct iovec *iov = iorw->fast_iov; int ret; ret = io_import_iovec(rw, req, &iov, &iorw->iter, false); if (unlikely(ret < 0)) return ret; iorw->bytes_done = 0; iorw->free_iovec = iov; if (iov) req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { ssize_t ret; ret = io_prep_rw(req, sqe); if (ret) return ret; if (unlikely(!(req->file->f_mode & FMODE_READ))) return -EBADF; /* either don't need iovec imported or already have it */ if (!req->async_data) return 0; return io_rw_prep_async(req, READ); } /* * This is our waitqueue callback handler, registered through lock_page_async() * when we initially tried to do the IO with the iocb armed our waitqueue. * This gets called when the page is unlocked, and we generally expect that to * happen when the page IO is completed and the page is now uptodate. This will * queue a task_work based retry of the operation, attempting to copy the data * again. If the latter fails because the page was NOT uptodate, then we will * do a thread based blocking retry of the operation. That's the unexpected * slow path. */ static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode, int sync, void *arg) { struct wait_page_queue *wpq; struct io_kiocb *req = wait->private; struct wait_page_key *key = arg; wpq = container_of(wait, struct wait_page_queue, wait); if (!wake_page_match(wpq, key)) return 0; req->rw.kiocb.ki_flags &= ~IOCB_WAITQ; list_del_init(&wait->entry); /* submit ref gets dropped, acquire a new one */ refcount_inc(&req->refs); io_req_task_queue(req); return 1; } /* * This controls whether a given IO request should be armed for async page * based retry. If we return false here, the request is handed to the async * worker threads for retry. If we're doing buffered reads on a regular file, * we prepare a private wait_page_queue entry and retry the operation. This * will either succeed because the page is now uptodate and unlocked, or it * will register a callback when the page is unlocked at IO completion. Through * that callback, io_uring uses task_work to setup a retry of the operation. * That retry will attempt the buffered read again. The retry will generally * succeed, or in rare cases where it fails, we then fall back to using the * async worker threads for a blocking retry. */ static bool io_rw_should_retry(struct io_kiocb *req) { struct io_async_rw *rw = req->async_data; struct wait_page_queue *wait = &rw->wpq; struct kiocb *kiocb = &req->rw.kiocb; /* never retry for NOWAIT, we just complete with -EAGAIN */ if (req->flags & REQ_F_NOWAIT) return false; /* Only for buffered IO */ if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI)) return false; /* * just use poll if we can, and don't attempt if the fs doesn't * support callback based unlocks */ if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC)) return false; wait->wait.func = io_async_buf_func; wait->wait.private = req; wait->wait.flags = 0; INIT_LIST_HEAD(&wait->wait.entry); kiocb->ki_flags |= IOCB_WAITQ; kiocb->ki_flags &= ~IOCB_NOWAIT; kiocb->ki_waitq = wait; return true; } static int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter) { if (req->file->f_op->read_iter) return call_read_iter(req->file, &req->rw.kiocb, iter); else if (req->file->f_op->read) return loop_rw_iter(READ, req, iter); else return -EINVAL; } static int io_read(struct io_kiocb *req, unsigned int issue_flags) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw.kiocb; struct iov_iter __iter, *iter = &__iter; struct io_async_rw *rw = req->async_data; ssize_t io_size, ret, ret2; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; if (rw) { iter = &rw->iter; iovec = NULL; } else { ret = io_import_iovec(READ, req, &iovec, iter, !force_nonblock); if (ret < 0) return ret; } io_size = iov_iter_count(iter); req->result = io_size; /* Ensure we clear previously set non-block flag */ if (!force_nonblock) kiocb->ki_flags &= ~IOCB_NOWAIT; else kiocb->ki_flags |= IOCB_NOWAIT; /* If the file doesn't support async, just async punt */ if (force_nonblock && !io_file_supports_async(req->file, READ)) { ret = io_setup_async_rw(req, iovec, inline_vecs, iter, true); return ret ?: -EAGAIN; } ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), io_size); if (unlikely(ret)) { kfree(iovec); return ret; } ret = io_iter_do_read(req, iter); if (ret == -EIOCBQUEUED) { goto out_free; } else if (ret == -EAGAIN) { /* IOPOLL retry should happen for io-wq threads */ if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL)) goto done; /* no retry on NONBLOCK nor RWF_NOWAIT */ if (req->flags & REQ_F_NOWAIT) goto done; /* some cases will consume bytes even on error returns */ iov_iter_revert(iter, io_size - iov_iter_count(iter)); ret = 0; } else if (ret <= 0 || ret == io_size || !force_nonblock || (req->flags & REQ_F_NOWAIT) || !(req->flags & REQ_F_ISREG)) { /* read all, failed, already did sync or don't want to retry */ goto done; } ret2 = io_setup_async_rw(req, iovec, inline_vecs, iter, true); if (ret2) return ret2; iovec = NULL; rw = req->async_data; /* now use our persistent iterator, if we aren't already */ iter = &rw->iter; do { io_size -= ret; rw->bytes_done += ret; /* if we can retry, do so with the callbacks armed */ if (!io_rw_should_retry(req)) { kiocb->ki_flags &= ~IOCB_WAITQ; return -EAGAIN; } /* * Now retry read with the IOCB_WAITQ parts set in the iocb. If * we get -EIOCBQUEUED, then we'll get a notification when the * desired page gets unlocked. We can also get a partial read * here, and if we do, then just retry at the new offset. */ ret = io_iter_do_read(req, iter); if (ret == -EIOCBQUEUED) return 0; /* we got some bytes, but not all. retry. */ } while (ret > 0 && ret < io_size); done: kiocb_done(kiocb, ret, issue_flags); out_free: /* it's faster to check here then delegate to kfree */ if (iovec) kfree(iovec); return 0; } static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { ssize_t ret; ret = io_prep_rw(req, sqe); if (ret) return ret; if (unlikely(!(req->file->f_mode & FMODE_WRITE))) return -EBADF; /* either don't need iovec imported or already have it */ if (!req->async_data) return 0; return io_rw_prep_async(req, WRITE); } static int io_write(struct io_kiocb *req, unsigned int issue_flags) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw.kiocb; struct iov_iter __iter, *iter = &__iter; struct io_async_rw *rw = req->async_data; ssize_t ret, ret2, io_size; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; if (rw) { iter = &rw->iter; iovec = NULL; } else { ret = io_import_iovec(WRITE, req, &iovec, iter, !force_nonblock); if (ret < 0) return ret; } io_size = iov_iter_count(iter); req->result = io_size; /* Ensure we clear previously set non-block flag */ if (!force_nonblock) kiocb->ki_flags &= ~IOCB_NOWAIT; else kiocb->ki_flags |= IOCB_NOWAIT; /* If the file doesn't support async, just async punt */ if (force_nonblock && !io_file_supports_async(req->file, WRITE)) goto copy_iov; /* file path doesn't support NOWAIT for non-direct_IO */ if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) && (req->flags & REQ_F_ISREG)) goto copy_iov; ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), io_size); if (unlikely(ret)) goto out_free; /* * Open-code file_start_write here to grab freeze protection, * which will be released by another thread in * io_complete_rw(). Fool lockdep by telling it the lock got * released so that it doesn't complain about the held lock when * we return to userspace. */ if (req->flags & REQ_F_ISREG) { sb_start_write(file_inode(req->file)->i_sb); __sb_writers_release(file_inode(req->file)->i_sb, SB_FREEZE_WRITE); } kiocb->ki_flags |= IOCB_WRITE; if (req->file->f_op->write_iter) ret2 = call_write_iter(req->file, kiocb, iter); else if (req->file->f_op->write) ret2 = loop_rw_iter(WRITE, req, iter); else ret2 = -EINVAL; /* * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just * retry them without IOCB_NOWAIT. */ if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) ret2 = -EAGAIN; /* no retry on NONBLOCK nor RWF_NOWAIT */ if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT)) goto done; if (!force_nonblock || ret2 != -EAGAIN) { /* IOPOLL retry should happen for io-wq threads */ if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN) goto copy_iov; done: kiocb_done(kiocb, ret2, issue_flags); } else { copy_iov: /* some cases will consume bytes even on error returns */ iov_iter_revert(iter, io_size - iov_iter_count(iter)); ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false); return ret ?: -EAGAIN; } out_free: /* it's reportedly faster than delegating the null check to kfree() */ if (iovec) kfree(iovec); return ret; } static int io_renameat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_rename *ren = &req->rename; const char __user *oldf, *newf; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; ren->old_dfd = READ_ONCE(sqe->fd); oldf = u64_to_user_ptr(READ_ONCE(sqe->addr)); newf = u64_to_user_ptr(READ_ONCE(sqe->addr2)); ren->new_dfd = READ_ONCE(sqe->len); ren->flags = READ_ONCE(sqe->rename_flags); ren->oldpath = getname(oldf); if (IS_ERR(ren->oldpath)) return PTR_ERR(ren->oldpath); ren->newpath = getname(newf); if (IS_ERR(ren->newpath)) { putname(ren->oldpath); return PTR_ERR(ren->newpath); } req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_renameat(struct io_kiocb *req, unsigned int issue_flags) { struct io_rename *ren = &req->rename; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = do_renameat2(ren->old_dfd, ren->oldpath, ren->new_dfd, ren->newpath, ren->flags); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_unlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_unlink *un = &req->unlink; const char __user *fname; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; un->dfd = READ_ONCE(sqe->fd); un->flags = READ_ONCE(sqe->unlink_flags); if (un->flags & ~AT_REMOVEDIR) return -EINVAL; fname = u64_to_user_ptr(READ_ONCE(sqe->addr)); un->filename = getname(fname); if (IS_ERR(un->filename)) return PTR_ERR(un->filename); req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags) { struct io_unlink *un = &req->unlink; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; if (un->flags & AT_REMOVEDIR) ret = do_rmdir(un->dfd, un->filename); else ret = do_unlinkat(un->dfd, un->filename); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_NET) if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->addr || sqe->rw_flags || sqe->buf_index) return -EINVAL; req->shutdown.how = READ_ONCE(sqe->len); return 0; #else return -EOPNOTSUPP; #endif } static int io_shutdown(struct io_kiocb *req, unsigned int issue_flags) { #if defined(CONFIG_NET) struct socket *sock; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; ret = __sys_shutdown_sock(sock, req->shutdown.how); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; #else return -EOPNOTSUPP; #endif } static int __io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_splice* sp = &req->splice; unsigned int valid_flags = SPLICE_F_FD_IN_FIXED | SPLICE_F_ALL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sp->file_in = NULL; sp->len = READ_ONCE(sqe->len); sp->flags = READ_ONCE(sqe->splice_flags); if (unlikely(sp->flags & ~valid_flags)) return -EINVAL; sp->file_in = io_file_get(NULL, req, READ_ONCE(sqe->splice_fd_in), (sp->flags & SPLICE_F_FD_IN_FIXED)); if (!sp->file_in) return -EBADF; req->flags |= REQ_F_NEED_CLEANUP; if (!S_ISREG(file_inode(sp->file_in)->i_mode)) { /* * Splice operation will be punted aync, and here need to * modify io_wq_work.flags, so initialize io_wq_work firstly. */ io_req_init_async(req); req->work.flags |= IO_WQ_WORK_UNBOUND; } return 0; } static int io_tee_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (READ_ONCE(sqe->splice_off_in) || READ_ONCE(sqe->off)) return -EINVAL; return __io_splice_prep(req, sqe); } static int io_tee(struct io_kiocb *req, unsigned int issue_flags) { struct io_splice *sp = &req->splice; struct file *in = sp->file_in; struct file *out = sp->file_out; unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED; long ret = 0; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; if (sp->len) ret = do_tee(in, out, sp->len, flags); io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED)); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret != sp->len) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_splice* sp = &req->splice; sp->off_in = READ_ONCE(sqe->splice_off_in); sp->off_out = READ_ONCE(sqe->off); return __io_splice_prep(req, sqe); } static int io_splice(struct io_kiocb *req, unsigned int issue_flags) { struct io_splice *sp = &req->splice; struct file *in = sp->file_in; struct file *out = sp->file_out; unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED; loff_t *poff_in, *poff_out; long ret = 0; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; poff_in = (sp->off_in == -1) ? NULL : &sp->off_in; poff_out = (sp->off_out == -1) ? NULL : &sp->off_out; if (sp->len) ret = do_splice(in, poff_in, out, poff_out, sp->len, flags); io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED)); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret != sp->len) req_set_fail_links(req); io_req_complete(req, ret); return 0; } /* * IORING_OP_NOP just posts a completion event, nothing else. */ static int io_nop(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; __io_req_complete(req, issue_flags, 0, 0); return 0; } static int io_fsync_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; if (!req->file) return -EBADF; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) return -EINVAL; req->sync.flags = READ_ONCE(sqe->fsync_flags); if (unlikely(req->sync.flags & ~IORING_FSYNC_DATASYNC)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->len); return 0; } static int io_fsync(struct io_kiocb *req, unsigned int issue_flags) { loff_t end = req->sync.off + req->sync.len; int ret; /* fsync always requires a blocking context */ if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = vfs_fsync_range(req->file, req->sync.off, end > 0 ? end : LLONG_MAX, req->sync.flags & IORING_FSYNC_DATASYNC); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_fallocate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (sqe->ioprio || sqe->buf_index || sqe->rw_flags) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->addr); req->sync.mode = READ_ONCE(sqe->len); return 0; } static int io_fallocate(struct io_kiocb *req, unsigned int issue_flags) { int ret; /* fallocate always requiring blocking context */ if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off, req->sync.len); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { const char __user *fname; int ret; if (unlikely(sqe->ioprio || sqe->buf_index)) return -EINVAL; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; /* open.how should be already initialised */ if (!(req->open.how.flags & O_PATH) && force_o_largefile()) req->open.how.flags |= O_LARGEFILE; req->open.dfd = READ_ONCE(sqe->fd); fname = u64_to_user_ptr(READ_ONCE(sqe->addr)); req->open.filename = getname(fname); if (IS_ERR(req->open.filename)) { ret = PTR_ERR(req->open.filename); req->open.filename = NULL; return ret; } req->open.nofile = rlimit(RLIMIT_NOFILE); req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { u64 flags, mode; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; mode = READ_ONCE(sqe->len); flags = READ_ONCE(sqe->open_flags); req->open.how = build_open_how(flags, mode); return __io_openat_prep(req, sqe); } static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct open_how __user *how; size_t len; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; how = u64_to_user_ptr(READ_ONCE(sqe->addr2)); len = READ_ONCE(sqe->len); if (len < OPEN_HOW_SIZE_VER0) return -EINVAL; ret = copy_struct_from_user(&req->open.how, sizeof(req->open.how), how, len); if (ret) return ret; return __io_openat_prep(req, sqe); } static int io_openat2(struct io_kiocb *req, unsigned int issue_flags) { struct open_flags op; struct file *file; bool nonblock_set; bool resolve_nonblock; int ret; ret = build_open_flags(&req->open.how, &op); if (ret) goto err; nonblock_set = op.open_flag & O_NONBLOCK; resolve_nonblock = req->open.how.resolve & RESOLVE_CACHED; if (issue_flags & IO_URING_F_NONBLOCK) { /* * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open, * it'll always -EAGAIN */ if (req->open.how.flags & (O_TRUNC | O_CREAT | O_TMPFILE)) return -EAGAIN; op.lookup_flags |= LOOKUP_CACHED; op.open_flag |= O_NONBLOCK; } ret = __get_unused_fd_flags(req->open.how.flags, req->open.nofile); if (ret < 0) goto err; file = do_filp_open(req->open.dfd, req->open.filename, &op); /* only retry if RESOLVE_CACHED wasn't already set by application */ if ((!resolve_nonblock && (issue_flags & IO_URING_F_NONBLOCK)) && file == ERR_PTR(-EAGAIN)) { /* * We could hang on to this 'fd', but seems like marginal * gain for something that is now known to be a slower path. * So just put it, and we'll get a new one when we retry. */ put_unused_fd(ret); return -EAGAIN; } if (IS_ERR(file)) { put_unused_fd(ret); ret = PTR_ERR(file); } else { if ((issue_flags & IO_URING_F_NONBLOCK) && !nonblock_set) file->f_flags &= ~O_NONBLOCK; fsnotify_open(file); fd_install(ret, file); } err: putname(req->open.filename); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_openat(struct io_kiocb *req, unsigned int issue_flags) { return io_openat2(req, issue_flags & IO_URING_F_NONBLOCK); } static int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_provide_buf *p = &req->pbuf; u64 tmp; if (sqe->ioprio || sqe->rw_flags || sqe->addr || sqe->len || sqe->off) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > USHRT_MAX) return -EINVAL; memset(p, 0, sizeof(*p)); p->nbufs = tmp; p->bgid = READ_ONCE(sqe->buf_group); return 0; } static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer *buf, int bgid, unsigned nbufs) { unsigned i = 0; /* shouldn't happen */ if (!nbufs) return 0; /* the head kbuf is the list itself */ while (!list_empty(&buf->list)) { struct io_buffer *nxt; nxt = list_first_entry(&buf->list, struct io_buffer, list); list_del(&nxt->list); kfree(nxt); if (++i == nbufs) return i; } i++; kfree(buf); idr_remove(&ctx->io_buffer_idr, bgid); return i; } static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags) { struct io_provide_buf *p = &req->pbuf; struct io_ring_ctx *ctx = req->ctx; struct io_buffer *head; int ret = 0; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; io_ring_submit_lock(ctx, !force_nonblock); lockdep_assert_held(&ctx->uring_lock); ret = -ENOENT; head = idr_find(&ctx->io_buffer_idr, p->bgid); if (head) ret = __io_remove_buffers(ctx, head, p->bgid, p->nbufs); if (ret < 0) req_set_fail_links(req); /* need to hold the lock to complete IOPOLL requests */ if (ctx->flags & IORING_SETUP_IOPOLL) { __io_req_complete(req, issue_flags, ret, 0); io_ring_submit_unlock(ctx, !force_nonblock); } else { io_ring_submit_unlock(ctx, !force_nonblock); __io_req_complete(req, issue_flags, ret, 0); } return 0; } static int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_provide_buf *p = &req->pbuf; u64 tmp; if (sqe->ioprio || sqe->rw_flags) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > USHRT_MAX) return -E2BIG; p->nbufs = tmp; p->addr = READ_ONCE(sqe->addr); p->len = READ_ONCE(sqe->len); if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs))) return -EFAULT; p->bgid = READ_ONCE(sqe->buf_group); tmp = READ_ONCE(sqe->off); if (tmp > USHRT_MAX) return -E2BIG; p->bid = tmp; return 0; } static int io_add_buffers(struct io_provide_buf *pbuf, struct io_buffer **head) { struct io_buffer *buf; u64 addr = pbuf->addr; int i, bid = pbuf->bid; for (i = 0; i < pbuf->nbufs; i++) { buf = kmalloc(sizeof(*buf), GFP_KERNEL); if (!buf) break; buf->addr = addr; buf->len = pbuf->len; buf->bid = bid; addr += pbuf->len; bid++; if (!*head) { INIT_LIST_HEAD(&buf->list); *head = buf; } else { list_add_tail(&buf->list, &(*head)->list); } } return i ? i : -ENOMEM; } static int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags) { struct io_provide_buf *p = &req->pbuf; struct io_ring_ctx *ctx = req->ctx; struct io_buffer *head, *list; int ret = 0; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; io_ring_submit_lock(ctx, !force_nonblock); lockdep_assert_held(&ctx->uring_lock); list = head = idr_find(&ctx->io_buffer_idr, p->bgid); ret = io_add_buffers(p, &head); if (ret < 0) goto out; if (!list) { ret = idr_alloc(&ctx->io_buffer_idr, head, p->bgid, p->bgid + 1, GFP_KERNEL); if (ret < 0) { __io_remove_buffers(ctx, head, p->bgid, -1U); goto out; } } out: if (ret < 0) req_set_fail_links(req); /* need to hold the lock to complete IOPOLL requests */ if (ctx->flags & IORING_SETUP_IOPOLL) { __io_req_complete(req, issue_flags, ret, 0); io_ring_submit_unlock(ctx, !force_nonblock); } else { io_ring_submit_unlock(ctx, !force_nonblock); __io_req_complete(req, issue_flags, ret, 0); } return 0; } static int io_epoll_ctl_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_EPOLL) if (sqe->ioprio || sqe->buf_index) return -EINVAL; if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL))) return -EINVAL; req->epoll.epfd = READ_ONCE(sqe->fd); req->epoll.op = READ_ONCE(sqe->len); req->epoll.fd = READ_ONCE(sqe->off); if (ep_op_has_event(req->epoll.op)) { struct epoll_event __user *ev; ev = u64_to_user_ptr(READ_ONCE(sqe->addr)); if (copy_from_user(&req->epoll.event, ev, sizeof(*ev))) return -EFAULT; } return 0; #else return -EOPNOTSUPP; #endif } static int io_epoll_ctl(struct io_kiocb *req, unsigned int issue_flags) { #if defined(CONFIG_EPOLL) struct io_epoll *ie = &req->epoll; int ret; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; ret = do_epoll_ctl(ie->epfd, ie->op, ie->fd, &ie->event, force_nonblock); if (force_nonblock && ret == -EAGAIN) return -EAGAIN; if (ret < 0) req_set_fail_links(req); __io_req_complete(req, issue_flags, ret, 0); return 0; #else return -EOPNOTSUPP; #endif } static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU) if (sqe->ioprio || sqe->buf_index || sqe->off) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->madvise.addr = READ_ONCE(sqe->addr); req->madvise.len = READ_ONCE(sqe->len); req->madvise.advice = READ_ONCE(sqe->fadvise_advice); return 0; #else return -EOPNOTSUPP; #endif } static int io_madvise(struct io_kiocb *req, unsigned int issue_flags) { #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU) struct io_madvise *ma = &req->madvise; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; #else return -EOPNOTSUPP; #endif } static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (sqe->ioprio || sqe->buf_index || sqe->addr) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->fadvise.offset = READ_ONCE(sqe->off); req->fadvise.len = READ_ONCE(sqe->len); req->fadvise.advice = READ_ONCE(sqe->fadvise_advice); return 0; } static int io_fadvise(struct io_kiocb *req, unsigned int issue_flags) { struct io_fadvise *fa = &req->fadvise; int ret; if (issue_flags & IO_URING_F_NONBLOCK) { switch (fa->advice) { case POSIX_FADV_NORMAL: case POSIX_FADV_RANDOM: case POSIX_FADV_SEQUENTIAL: break; default: return -EAGAIN; } } ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL))) return -EINVAL; if (sqe->ioprio || sqe->buf_index) return -EINVAL; if (req->flags & REQ_F_FIXED_FILE) return -EBADF; req->statx.dfd = READ_ONCE(sqe->fd); req->statx.mask = READ_ONCE(sqe->len); req->statx.filename = u64_to_user_ptr(READ_ONCE(sqe->addr)); req->statx.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2)); req->statx.flags = READ_ONCE(sqe->statx_flags); return 0; } static int io_statx(struct io_kiocb *req, unsigned int issue_flags) { struct io_statx *ctx = &req->statx; int ret; if (issue_flags & IO_URING_F_NONBLOCK) { /* only need file table for an actual valid fd */ if (ctx->dfd == -1 || ctx->dfd == AT_FDCWD) req->flags |= REQ_F_NO_FILE_TABLE; return -EAGAIN; } ret = do_statx(ctx->dfd, ctx->filename, ctx->flags, ctx->mask, ctx->buffer); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index) return -EINVAL; if (req->flags & REQ_F_FIXED_FILE) return -EBADF; req->close.fd = READ_ONCE(sqe->fd); return 0; } static int io_close(struct io_kiocb *req, unsigned int issue_flags) { struct files_struct *files = current->files; struct io_close *close = &req->close; struct fdtable *fdt; struct file *file; int ret; file = NULL; ret = -EBADF; spin_lock(&files->file_lock); fdt = files_fdtable(files); if (close->fd >= fdt->max_fds) { spin_unlock(&files->file_lock); goto err; } file = fdt->fd[close->fd]; if (!file) { spin_unlock(&files->file_lock); goto err; } if (file->f_op == &io_uring_fops) { spin_unlock(&files->file_lock); file = NULL; goto err; } /* if the file has a flush method, be safe and punt to async */ if (file->f_op->flush && (issue_flags & IO_URING_F_NONBLOCK)) { spin_unlock(&files->file_lock); return -EAGAIN; } ret = __close_fd_get_file(close->fd, &file); spin_unlock(&files->file_lock); if (ret < 0) { if (ret == -ENOENT) ret = -EBADF; goto err; } /* No ->flush() or already async, safely close from here */ ret = filp_close(file, current->files); err: if (ret < 0) req_set_fail_links(req); if (file) fput(file); __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_sfr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->len); req->sync.flags = READ_ONCE(sqe->sync_range_flags); return 0; } static int io_sync_file_range(struct io_kiocb *req, unsigned int issue_flags) { int ret; /* sync_file_range always requires a blocking context */ if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = sync_file_range(req->file, req->sync.off, req->sync.len, req->sync.flags); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } #if defined(CONFIG_NET) static int io_setup_async_msg(struct io_kiocb *req, struct io_async_msghdr *kmsg) { struct io_async_msghdr *async_msg = req->async_data; if (async_msg) return -EAGAIN; if (io_alloc_async_data(req)) { kfree(kmsg->free_iov); return -ENOMEM; } async_msg = req->async_data; req->flags |= REQ_F_NEED_CLEANUP; memcpy(async_msg, kmsg, sizeof(*kmsg)); async_msg->msg.msg_name = &async_msg->addr; /* if were using fast_iov, set it to the new one */ if (!async_msg->free_iov) async_msg->msg.msg_iter.iov = async_msg->fast_iov; return -EAGAIN; } static int io_sendmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { iomsg->msg.msg_name = &iomsg->addr; iomsg->free_iov = iomsg->fast_iov; return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg, req->sr_msg.msg_flags, &iomsg->free_iov); } static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_async_msghdr *async_msg = req->async_data; struct io_sr_msg *sr = &req->sr_msg; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sr->msg_flags = READ_ONCE(sqe->msg_flags); sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr)); sr->len = READ_ONCE(sqe->len); #ifdef CONFIG_COMPAT if (req->ctx->compat) sr->msg_flags |= MSG_CMSG_COMPAT; #endif if (!async_msg || !io_op_defs[req->opcode].needs_async_data) return 0; ret = io_sendmsg_copy_hdr(req, async_msg); if (!ret) req->flags |= REQ_F_NEED_CLEANUP; return ret; } static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags) { struct io_async_msghdr iomsg, *kmsg; struct socket *sock; unsigned flags; int ret; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; kmsg = req->async_data; if (!kmsg) { ret = io_sendmsg_copy_hdr(req, &iomsg); if (ret) return ret; kmsg = &iomsg; } flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (issue_flags & IO_URING_F_NONBLOCK) flags |= MSG_DONTWAIT; ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags); if ((issue_flags & IO_URING_F_NONBLOCK) && ret == -EAGAIN) return io_setup_async_msg(req, kmsg); if (ret == -ERESTARTSYS) ret = -EINTR; /* fast path, check for non-NULL to avoid function call */ if (kmsg->free_iov) kfree(kmsg->free_iov); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail_links(req); __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_send(struct io_kiocb *req, unsigned int issue_flags) { struct io_sr_msg *sr = &req->sr_msg; struct msghdr msg; struct iovec iov; struct socket *sock; unsigned flags; int ret; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter); if (unlikely(ret)) return ret; msg.msg_name = NULL; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_namelen = 0; flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (issue_flags & IO_URING_F_NONBLOCK) flags |= MSG_DONTWAIT; msg.msg_flags = flags; ret = sock_sendmsg(sock, &msg); if ((issue_flags & IO_URING_F_NONBLOCK) && ret == -EAGAIN) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; if (ret < 0) req_set_fail_links(req); __io_req_complete(req, issue_flags, ret, 0); return 0; } static int __io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { struct io_sr_msg *sr = &req->sr_msg; struct iovec __user *uiov; size_t iov_len; int ret; ret = __copy_msghdr_from_user(&iomsg->msg, sr->umsg, &iomsg->uaddr, &uiov, &iov_len); if (ret) return ret; if (req->flags & REQ_F_BUFFER_SELECT) { if (iov_len > 1) return -EINVAL; if (copy_from_user(iomsg->fast_iov, uiov, sizeof(*uiov))) return -EFAULT; sr->len = iomsg->fast_iov[0].iov_len; iomsg->free_iov = NULL; } else { iomsg->free_iov = iomsg->fast_iov; ret = __import_iovec(READ, uiov, iov_len, UIO_FASTIOV, &iomsg->free_iov, &iomsg->msg.msg_iter, false); if (ret > 0) ret = 0; } return ret; } #ifdef CONFIG_COMPAT static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { struct compat_msghdr __user *msg_compat; struct io_sr_msg *sr = &req->sr_msg; struct compat_iovec __user *uiov; compat_uptr_t ptr; compat_size_t len; int ret; msg_compat = (struct compat_msghdr __user *) sr->umsg; ret = __get_compat_msghdr(&iomsg->msg, msg_compat, &iomsg->uaddr, &ptr, &len); if (ret) return ret; uiov = compat_ptr(ptr); if (req->flags & REQ_F_BUFFER_SELECT) { compat_ssize_t clen; if (len > 1) return -EINVAL; if (!access_ok(uiov, sizeof(*uiov))) return -EFAULT; if (__get_user(clen, &uiov->iov_len)) return -EFAULT; if (clen < 0) return -EINVAL; sr->len = clen; iomsg->free_iov = NULL; } else { iomsg->free_iov = iomsg->fast_iov; ret = __import_iovec(READ, (struct iovec __user *)uiov, len, UIO_FASTIOV, &iomsg->free_iov, &iomsg->msg.msg_iter, true); if (ret < 0) return ret; } return 0; } #endif static int io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { iomsg->msg.msg_name = &iomsg->addr; #ifdef CONFIG_COMPAT if (req->ctx->compat) return __io_compat_recvmsg_copy_hdr(req, iomsg); #endif return __io_recvmsg_copy_hdr(req, iomsg); } static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req, bool needs_lock) { struct io_sr_msg *sr = &req->sr_msg; struct io_buffer *kbuf; kbuf = io_buffer_select(req, &sr->len, sr->bgid, sr->kbuf, needs_lock); if (IS_ERR(kbuf)) return kbuf; sr->kbuf = kbuf; req->flags |= REQ_F_BUFFER_SELECTED; return kbuf; } static inline unsigned int io_put_recv_kbuf(struct io_kiocb *req) { return io_put_kbuf(req, req->sr_msg.kbuf); } static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_async_msghdr *async_msg = req->async_data; struct io_sr_msg *sr = &req->sr_msg; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sr->msg_flags = READ_ONCE(sqe->msg_flags); sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr)); sr->len = READ_ONCE(sqe->len); sr->bgid = READ_ONCE(sqe->buf_group); #ifdef CONFIG_COMPAT if (req->ctx->compat) sr->msg_flags |= MSG_CMSG_COMPAT; #endif if (!async_msg || !io_op_defs[req->opcode].needs_async_data) return 0; ret = io_recvmsg_copy_hdr(req, async_msg); if (!ret) req->flags |= REQ_F_NEED_CLEANUP; return ret; } static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) { struct io_async_msghdr iomsg, *kmsg; struct socket *sock; struct io_buffer *kbuf; unsigned flags; int ret, cflags = 0; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; kmsg = req->async_data; if (!kmsg) { ret = io_recvmsg_copy_hdr(req, &iomsg); if (ret) return ret; kmsg = &iomsg; } if (req->flags & REQ_F_BUFFER_SELECT) { kbuf = io_recv_buffer_select(req, !force_nonblock); if (IS_ERR(kbuf)) return PTR_ERR(kbuf); kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr); kmsg->fast_iov[0].iov_len = req->sr_msg.len; iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov, 1, req->sr_msg.len); } flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg, kmsg->uaddr, flags); if (force_nonblock && ret == -EAGAIN) return io_setup_async_msg(req, kmsg); if (ret == -ERESTARTSYS) ret = -EINTR; if (req->flags & REQ_F_BUFFER_SELECTED) cflags = io_put_recv_kbuf(req); /* fast path, check for non-NULL to avoid function call */ if (kmsg->free_iov) kfree(kmsg->free_iov); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail_links(req); __io_req_complete(req, issue_flags, ret, cflags); return 0; } static int io_recv(struct io_kiocb *req, unsigned int issue_flags) { struct io_buffer *kbuf; struct io_sr_msg *sr = &req->sr_msg; struct msghdr msg; void __user *buf = sr->buf; struct socket *sock; struct iovec iov; unsigned flags; int ret, cflags = 0; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; if (req->flags & REQ_F_BUFFER_SELECT) { kbuf = io_recv_buffer_select(req, !force_nonblock); if (IS_ERR(kbuf)) return PTR_ERR(kbuf); buf = u64_to_user_ptr(kbuf->addr); } ret = import_single_range(READ, buf, sr->len, &iov, &msg.msg_iter); if (unlikely(ret)) goto out_free; msg.msg_name = NULL; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_namelen = 0; msg.msg_iocb = NULL; msg.msg_flags = 0; flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; ret = sock_recvmsg(sock, &msg, flags); if (force_nonblock && ret == -EAGAIN) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; out_free: if (req->flags & REQ_F_BUFFER_SELECTED) cflags = io_put_recv_kbuf(req); if (ret < 0) req_set_fail_links(req); __io_req_complete(req, issue_flags, ret, cflags); return 0; } static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_accept *accept = &req->accept; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->len || sqe->buf_index) return -EINVAL; accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2)); accept->flags = READ_ONCE(sqe->accept_flags); accept->nofile = rlimit(RLIMIT_NOFILE); return 0; } static int io_accept(struct io_kiocb *req, unsigned int issue_flags) { struct io_accept *accept = &req->accept; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0; int ret; if (req->file->f_flags & O_NONBLOCK) req->flags |= REQ_F_NOWAIT; ret = __sys_accept4_file(req->file, file_flags, accept->addr, accept->addr_len, accept->flags, accept->nofile); if (ret == -EAGAIN && force_nonblock) return -EAGAIN; if (ret < 0) { if (ret == -ERESTARTSYS) ret = -EINTR; req_set_fail_links(req); } __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_connect *conn = &req->connect; struct io_async_connect *io = req->async_data; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags) return -EINVAL; conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); conn->addr_len = READ_ONCE(sqe->addr2); if (!io) return 0; return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address); } static int io_connect(struct io_kiocb *req, unsigned int issue_flags) { struct io_async_connect __io, *io; unsigned file_flags; int ret; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; if (req->async_data) { io = req->async_data; } else { ret = move_addr_to_kernel(req->connect.addr, req->connect.addr_len, &__io.address); if (ret) goto out; io = &__io; } file_flags = force_nonblock ? O_NONBLOCK : 0; ret = __sys_connect_file(req->file, &io->address, req->connect.addr_len, file_flags); if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) { if (req->async_data) return -EAGAIN; if (io_alloc_async_data(req)) { ret = -ENOMEM; goto out; } io = req->async_data; memcpy(req->async_data, &__io, sizeof(__io)); return -EAGAIN; } if (ret == -ERESTARTSYS) ret = -EINTR; out: if (ret < 0) req_set_fail_links(req); __io_req_complete(req, issue_flags, ret, 0); return 0; } #else /* !CONFIG_NET */ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return -EOPNOTSUPP; } static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags) { return -EOPNOTSUPP; } static int io_send(struct io_kiocb *req, unsigned int issue_flags) { return -EOPNOTSUPP; } static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return -EOPNOTSUPP; } static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) { return -EOPNOTSUPP; } static int io_recv(struct io_kiocb *req, unsigned int issue_flags) { return -EOPNOTSUPP; } static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return -EOPNOTSUPP; } static int io_accept(struct io_kiocb *req, unsigned int issue_flags) { return -EOPNOTSUPP; } static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return -EOPNOTSUPP; } static int io_connect(struct io_kiocb *req, unsigned int issue_flags) { return -EOPNOTSUPP; } #endif /* CONFIG_NET */ struct io_poll_table { struct poll_table_struct pt; struct io_kiocb *req; int error; }; static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll, __poll_t mask, task_work_func_t func) { int ret; /* for instances that support it check for an event match first: */ if (mask && !(mask & poll->events)) return 0; trace_io_uring_task_add(req->ctx, req->opcode, req->user_data, mask); list_del_init(&poll->wait.entry); req->result = mask; req->task_work.func = func; percpu_ref_get(&req->ctx->refs); /* * If this fails, then the task is exiting. When a task exits, the * work gets canceled, so just cancel this request as well instead * of executing it. We can't safely execute it anyway, as we may not * have the needed state needed for it anyway. */ ret = io_req_task_work_add(req); if (unlikely(ret)) { WRITE_ONCE(poll->canceled, true); io_req_task_work_add_fallback(req, func); } return 1; } static bool io_poll_rewait(struct io_kiocb *req, struct io_poll_iocb *poll) __acquires(&req->ctx->completion_lock) { struct io_ring_ctx *ctx = req->ctx; if (!req->result && !READ_ONCE(poll->canceled)) { struct poll_table_struct pt = { ._key = poll->events }; req->result = vfs_poll(req->file, &pt) & poll->events; } spin_lock_irq(&ctx->completion_lock); if (!req->result && !READ_ONCE(poll->canceled)) { add_wait_queue(poll->head, &poll->wait); return true; } return false; } static struct io_poll_iocb *io_poll_get_double(struct io_kiocb *req) { /* pure poll stashes this in ->async_data, poll driven retry elsewhere */ if (req->opcode == IORING_OP_POLL_ADD) return req->async_data; return req->apoll->double_poll; } static struct io_poll_iocb *io_poll_get_single(struct io_kiocb *req) { if (req->opcode == IORING_OP_POLL_ADD) return &req->poll; return &req->apoll->poll; } static void io_poll_remove_double(struct io_kiocb *req) { struct io_poll_iocb *poll = io_poll_get_double(req); lockdep_assert_held(&req->ctx->completion_lock); if (poll && poll->head) { struct wait_queue_head *head = poll->head; spin_lock(&head->lock); list_del_init(&poll->wait.entry); if (poll->wait.private) refcount_dec(&req->refs); poll->head = NULL; spin_unlock(&head->lock); } } static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error) { struct io_ring_ctx *ctx = req->ctx; io_poll_remove_double(req); req->poll.done = true; io_cqring_fill_event(req, error ? error : mangle_poll(mask)); io_commit_cqring(ctx); } static void io_poll_task_func(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *nxt; if (io_poll_rewait(req, &req->poll)) { spin_unlock_irq(&ctx->completion_lock); } else { hash_del(&req->hash_node); io_poll_complete(req, req->result, 0); spin_unlock_irq(&ctx->completion_lock); nxt = io_put_req_find_next(req); io_cqring_ev_posted(ctx); if (nxt) __io_req_task_submit(nxt); } percpu_ref_put(&ctx->refs); } static int io_poll_double_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct io_kiocb *req = wait->private; struct io_poll_iocb *poll = io_poll_get_single(req); __poll_t mask = key_to_poll(key); /* for instances that support it check for an event match first: */ if (mask && !(mask & poll->events)) return 0; list_del_init(&wait->entry); if (poll && poll->head) { bool done; spin_lock(&poll->head->lock); done = list_empty(&poll->wait.entry); if (!done) list_del_init(&poll->wait.entry); /* make sure double remove sees this as being gone */ wait->private = NULL; spin_unlock(&poll->head->lock); if (!done) { /* use wait func handler, so it matches the rq type */ poll->wait.func(&poll->wait, mode, sync, key); } } refcount_dec(&req->refs); return 1; } static void io_init_poll_iocb(struct io_poll_iocb *poll, __poll_t events, wait_queue_func_t wake_func) { poll->head = NULL; poll->done = false; poll->canceled = false; poll->events = events; INIT_LIST_HEAD(&poll->wait.entry); init_waitqueue_func_entry(&poll->wait, wake_func); } static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt, struct wait_queue_head *head, struct io_poll_iocb **poll_ptr) { struct io_kiocb *req = pt->req; /* * If poll->head is already set, it's because the file being polled * uses multiple waitqueues for poll handling (eg one for read, one * for write). Setup a separate io_poll_iocb if this happens. */ if (unlikely(poll->head)) { struct io_poll_iocb *poll_one = poll; /* already have a 2nd entry, fail a third attempt */ if (*poll_ptr) { pt->error = -EINVAL; return; } poll = kmalloc(sizeof(*poll), GFP_ATOMIC); if (!poll) { pt->error = -ENOMEM; return; } io_init_poll_iocb(poll, poll_one->events, io_poll_double_wake); refcount_inc(&req->refs); poll->wait.private = req; *poll_ptr = poll; } pt->error = 0; poll->head = head; if (poll->events & EPOLLEXCLUSIVE) add_wait_queue_exclusive(head, &poll->wait); else add_wait_queue(head, &poll->wait); } static void io_async_queue_proc(struct file *file, struct wait_queue_head *head, struct poll_table_struct *p) { struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); struct async_poll *apoll = pt->req->apoll; __io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll); } static void io_async_task_func(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); struct async_poll *apoll = req->apoll; struct io_ring_ctx *ctx = req->ctx; trace_io_uring_task_run(req->ctx, req->opcode, req->user_data); if (io_poll_rewait(req, &apoll->poll)) { spin_unlock_irq(&ctx->completion_lock); percpu_ref_put(&ctx->refs); return; } /* If req is still hashed, it cannot have been canceled. Don't check. */ if (hash_hashed(&req->hash_node)) hash_del(&req->hash_node); io_poll_remove_double(req); spin_unlock_irq(&ctx->completion_lock); if (!READ_ONCE(apoll->poll.canceled)) __io_req_task_submit(req); else __io_req_task_cancel(req, -ECANCELED); percpu_ref_put(&ctx->refs); kfree(apoll->double_poll); kfree(apoll); } static int io_async_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct io_kiocb *req = wait->private; struct io_poll_iocb *poll = &req->apoll->poll; trace_io_uring_poll_wake(req->ctx, req->opcode, req->user_data, key_to_poll(key)); return __io_async_wake(req, poll, key_to_poll(key), io_async_task_func); } static void io_poll_req_insert(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct hlist_head *list; list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)]; hlist_add_head(&req->hash_node, list); } static __poll_t __io_arm_poll_handler(struct io_kiocb *req, struct io_poll_iocb *poll, struct io_poll_table *ipt, __poll_t mask, wait_queue_func_t wake_func) __acquires(&ctx->completion_lock) { struct io_ring_ctx *ctx = req->ctx; bool cancel = false; INIT_HLIST_NODE(&req->hash_node); io_init_poll_iocb(poll, mask, wake_func); poll->file = req->file; poll->wait.private = req; ipt->pt._key = mask; ipt->req = req; ipt->error = -EINVAL; mask = vfs_poll(req->file, &ipt->pt) & poll->events; spin_lock_irq(&ctx->completion_lock); if (likely(poll->head)) { spin_lock(&poll->head->lock); if (unlikely(list_empty(&poll->wait.entry))) { if (ipt->error) cancel = true; ipt->error = 0; mask = 0; } if (mask || ipt->error) list_del_init(&poll->wait.entry); else if (cancel) WRITE_ONCE(poll->canceled, true); else if (!poll->done) /* actually waiting for an event */ io_poll_req_insert(req); spin_unlock(&poll->head->lock); } return mask; } static bool io_arm_poll_handler(struct io_kiocb *req) { const struct io_op_def *def = &io_op_defs[req->opcode]; struct io_ring_ctx *ctx = req->ctx; struct async_poll *apoll; struct io_poll_table ipt; __poll_t mask, ret; int rw; if (!req->file || !file_can_poll(req->file)) return false; if (req->flags & REQ_F_POLLED) return false; if (def->pollin) rw = READ; else if (def->pollout) rw = WRITE; else return false; /* if we can't nonblock try, then no point in arming a poll handler */ if (!io_file_supports_async(req->file, rw)) return false; apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC); if (unlikely(!apoll)) return false; apoll->double_poll = NULL; req->flags |= REQ_F_POLLED; req->apoll = apoll; mask = 0; if (def->pollin) mask |= POLLIN | POLLRDNORM; if (def->pollout) mask |= POLLOUT | POLLWRNORM; /* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */ if ((req->opcode == IORING_OP_RECVMSG) && (req->sr_msg.msg_flags & MSG_ERRQUEUE)) mask &= ~POLLIN; mask |= POLLERR | POLLPRI; ipt.pt._qproc = io_async_queue_proc; ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask, io_async_wake); if (ret || ipt.error) { io_poll_remove_double(req); spin_unlock_irq(&ctx->completion_lock); kfree(apoll->double_poll); kfree(apoll); return false; } spin_unlock_irq(&ctx->completion_lock); trace_io_uring_poll_arm(ctx, req->opcode, req->user_data, mask, apoll->poll.events); return true; } static bool __io_poll_remove_one(struct io_kiocb *req, struct io_poll_iocb *poll) { bool do_complete = false; spin_lock(&poll->head->lock); WRITE_ONCE(poll->canceled, true); if (!list_empty(&poll->wait.entry)) { list_del_init(&poll->wait.entry); do_complete = true; } spin_unlock(&poll->head->lock); hash_del(&req->hash_node); return do_complete; } static bool io_poll_remove_one(struct io_kiocb *req) { bool do_complete; io_poll_remove_double(req); if (req->opcode == IORING_OP_POLL_ADD) { do_complete = __io_poll_remove_one(req, &req->poll); } else { struct async_poll *apoll = req->apoll; /* non-poll requests have submit ref still */ do_complete = __io_poll_remove_one(req, &apoll->poll); if (do_complete) { io_put_req(req); kfree(apoll->double_poll); kfree(apoll); } } if (do_complete) { io_cqring_fill_event(req, -ECANCELED); io_commit_cqring(req->ctx); req_set_fail_links(req); io_put_req_deferred(req, 1); } return do_complete; } /* * Returns true if we found and killed one or more poll requests */ static bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk, struct files_struct *files) { struct hlist_node *tmp; struct io_kiocb *req; int posted = 0, i; spin_lock_irq(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { struct hlist_head *list; list = &ctx->cancel_hash[i]; hlist_for_each_entry_safe(req, tmp, list, hash_node) { if (io_match_task(req, tsk, files)) posted += io_poll_remove_one(req); } } spin_unlock_irq(&ctx->completion_lock); if (posted) io_cqring_ev_posted(ctx); return posted != 0; } static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr) { struct hlist_head *list; struct io_kiocb *req; list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)]; hlist_for_each_entry(req, list, hash_node) { if (sqe_addr != req->user_data) continue; if (io_poll_remove_one(req)) return 0; return -EALREADY; } return -ENOENT; } static int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index || sqe->poll_events) return -EINVAL; req->poll_remove.addr = READ_ONCE(sqe->addr); return 0; } /* * Find a running poll command that matches one specified in sqe->addr, * and remove it if found. */ static int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; int ret; spin_lock_irq(&ctx->completion_lock); ret = io_poll_cancel(ctx, req->poll_remove.addr); spin_unlock_irq(&ctx->completion_lock); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct io_kiocb *req = wait->private; struct io_poll_iocb *poll = &req->poll; return __io_async_wake(req, poll, key_to_poll(key), io_poll_task_func); } static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, struct poll_table_struct *p) { struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); __io_queue_proc(&pt->req->poll, pt, head, (struct io_poll_iocb **) &pt->req->async_data); } static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_poll_iocb *poll = &req->poll; u32 events; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index) return -EINVAL; events = READ_ONCE(sqe->poll32_events); #ifdef __BIG_ENDIAN events = swahw32(events); #endif poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP | (events & EPOLLEXCLUSIVE); return 0; } static int io_poll_add(struct io_kiocb *req, unsigned int issue_flags) { struct io_poll_iocb *poll = &req->poll; struct io_ring_ctx *ctx = req->ctx; struct io_poll_table ipt; __poll_t mask; ipt.pt._qproc = io_poll_queue_proc; mask = __io_arm_poll_handler(req, &req->poll, &ipt, poll->events, io_poll_wake); if (mask) { /* no async, we'd stolen it */ ipt.error = 0; io_poll_complete(req, mask, 0); } spin_unlock_irq(&ctx->completion_lock); if (mask) { io_cqring_ev_posted(ctx); io_put_req(req); } return ipt.error; } static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *req = data->req; struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); list_del_init(&req->timeout.list); atomic_set(&req->ctx->cq_timeouts, atomic_read(&req->ctx->cq_timeouts) + 1); io_cqring_fill_event(req, -ETIME); io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); req_set_fail_links(req); io_put_req(req); return HRTIMER_NORESTART; } static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx, __u64 user_data) { struct io_timeout_data *io; struct io_kiocb *req; int ret = -ENOENT; list_for_each_entry(req, &ctx->timeout_list, timeout.list) { if (user_data == req->user_data) { ret = 0; break; } } if (ret == -ENOENT) return ERR_PTR(ret); io = req->async_data; ret = hrtimer_try_to_cancel(&io->timer); if (ret == -1) return ERR_PTR(-EALREADY); list_del_init(&req->timeout.list); return req; } static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data) { struct io_kiocb *req = io_timeout_extract(ctx, user_data); if (IS_ERR(req)) return PTR_ERR(req); req_set_fail_links(req); io_cqring_fill_event(req, -ECANCELED); io_put_req_deferred(req, 1); return 0; } static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data, struct timespec64 *ts, enum hrtimer_mode mode) { struct io_kiocb *req = io_timeout_extract(ctx, user_data); struct io_timeout_data *data; if (IS_ERR(req)) return PTR_ERR(req); req->timeout.off = 0; /* noseq */ data = req->async_data; list_add_tail(&req->timeout.list, &ctx->timeout_list); hrtimer_init(&data->timer, CLOCK_MONOTONIC, mode); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode); return 0; } static int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_timeout_rem *tr = &req->timeout_rem; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->len) return -EINVAL; tr->addr = READ_ONCE(sqe->addr); tr->flags = READ_ONCE(sqe->timeout_flags); if (tr->flags & IORING_TIMEOUT_UPDATE) { if (tr->flags & ~(IORING_TIMEOUT_UPDATE|IORING_TIMEOUT_ABS)) return -EINVAL; if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2))) return -EFAULT; } else if (tr->flags) { /* timeout removal doesn't support flags */ return -EINVAL; } return 0; } static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags) { return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL; } /* * Remove or update an existing timeout command */ static int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags) { struct io_timeout_rem *tr = &req->timeout_rem; struct io_ring_ctx *ctx = req->ctx; int ret; spin_lock_irq(&ctx->completion_lock); if (!(req->timeout_rem.flags & IORING_TIMEOUT_UPDATE)) ret = io_timeout_cancel(ctx, tr->addr); else ret = io_timeout_update(ctx, tr->addr, &tr->ts, io_translate_timeout_mode(tr->flags)); io_cqring_fill_event(req, ret); io_commit_cqring(ctx); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); if (ret < 0) req_set_fail_links(req); io_put_req(req); return 0; } static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool is_timeout_link) { struct io_timeout_data *data; unsigned flags; u32 off = READ_ONCE(sqe->off); if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->len != 1) return -EINVAL; if (off && is_timeout_link) return -EINVAL; flags = READ_ONCE(sqe->timeout_flags); if (flags & ~IORING_TIMEOUT_ABS) return -EINVAL; req->timeout.off = off; if (!req->async_data && io_alloc_async_data(req)) return -ENOMEM; data = req->async_data; data->req = req; if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr))) return -EFAULT; data->mode = io_translate_timeout_mode(flags); hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode); return 0; } static int io_timeout(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; struct io_timeout_data *data = req->async_data; struct list_head *entry; u32 tail, off = req->timeout.off; spin_lock_irq(&ctx->completion_lock); /* * sqe->off holds how many events that need to occur for this * timeout event to be satisfied. If it isn't set, then this is * a pure timeout request, sequence isn't used. */ if (io_is_timeout_noseq(req)) { entry = ctx->timeout_list.prev; goto add; } tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts); req->timeout.target_seq = tail + off; /* Update the last seq here in case io_flush_timeouts() hasn't. * This is safe because ->completion_lock is held, and submissions * and completions are never mixed in the same ->completion_lock section. */ ctx->cq_last_tm_flush = tail; /* * Insertion sort, ensuring the first entry in the list is always * the one we need first. */ list_for_each_prev(entry, &ctx->timeout_list) { struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, timeout.list); if (io_is_timeout_noseq(nxt)) continue; /* nxt.seq is behind @tail, otherwise would've been completed */ if (off >= nxt->timeout.target_seq - tail) break; } add: list_add(&req->timeout.list, entry); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); spin_unlock_irq(&ctx->completion_lock); return 0; } static bool io_cancel_cb(struct io_wq_work *work, void *data) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); return req->user_data == (unsigned long) data; } static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr) { enum io_wq_cancel cancel_ret; int ret = 0; cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr, false); switch (cancel_ret) { case IO_WQ_CANCEL_OK: ret = 0; break; case IO_WQ_CANCEL_RUNNING: ret = -EALREADY; break; case IO_WQ_CANCEL_NOTFOUND: ret = -ENOENT; break; } return ret; } static void io_async_find_and_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req, __u64 sqe_addr, int success_ret) { unsigned long flags; int ret; ret = io_async_cancel_one(ctx, (void *) (unsigned long) sqe_addr); if (ret != -ENOENT) { spin_lock_irqsave(&ctx->completion_lock, flags); goto done; } spin_lock_irqsave(&ctx->completion_lock, flags); ret = io_timeout_cancel(ctx, sqe_addr); if (ret != -ENOENT) goto done; ret = io_poll_cancel(ctx, sqe_addr); done: if (!ret) ret = success_ret; io_cqring_fill_event(req, ret); io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); if (ret < 0) req_set_fail_links(req); io_put_req(req); } static int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->len || sqe->cancel_flags) return -EINVAL; req->cancel.addr = READ_ONCE(sqe->addr); return 0; } static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; io_async_find_and_cancel(ctx, req, req->cancel.addr, 0); return 0; } static int io_rsrc_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_SQPOLL)) return -EINVAL; if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->ioprio || sqe->rw_flags) return -EINVAL; req->rsrc_update.offset = READ_ONCE(sqe->off); req->rsrc_update.nr_args = READ_ONCE(sqe->len); if (!req->rsrc_update.nr_args) return -EINVAL; req->rsrc_update.arg = READ_ONCE(sqe->addr); return 0; } static int io_files_update(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; struct io_uring_rsrc_update up; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; up.offset = req->rsrc_update.offset; up.data = req->rsrc_update.arg; mutex_lock(&ctx->uring_lock); ret = __io_sqe_files_update(ctx, &up, req->rsrc_update.nr_args); mutex_unlock(&ctx->uring_lock); if (ret < 0) req_set_fail_links(req); __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { switch (req->opcode) { case IORING_OP_NOP: return 0; case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: return io_read_prep(req, sqe); case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: return io_write_prep(req, sqe); case IORING_OP_POLL_ADD: return io_poll_add_prep(req, sqe); case IORING_OP_POLL_REMOVE: return io_poll_remove_prep(req, sqe); case IORING_OP_FSYNC: return io_fsync_prep(req, sqe); case IORING_OP_SYNC_FILE_RANGE: return io_sfr_prep(req, sqe); case IORING_OP_SENDMSG: case IORING_OP_SEND: return io_sendmsg_prep(req, sqe); case IORING_OP_RECVMSG: case IORING_OP_RECV: return io_recvmsg_prep(req, sqe); case IORING_OP_CONNECT: return io_connect_prep(req, sqe); case IORING_OP_TIMEOUT: return io_timeout_prep(req, sqe, false); case IORING_OP_TIMEOUT_REMOVE: return io_timeout_remove_prep(req, sqe); case IORING_OP_ASYNC_CANCEL: return io_async_cancel_prep(req, sqe); case IORING_OP_LINK_TIMEOUT: return io_timeout_prep(req, sqe, true); case IORING_OP_ACCEPT: return io_accept_prep(req, sqe); case IORING_OP_FALLOCATE: return io_fallocate_prep(req, sqe); case IORING_OP_OPENAT: return io_openat_prep(req, sqe); case IORING_OP_CLOSE: return io_close_prep(req, sqe); case IORING_OP_FILES_UPDATE: return io_rsrc_update_prep(req, sqe); case IORING_OP_STATX: return io_statx_prep(req, sqe); case IORING_OP_FADVISE: return io_fadvise_prep(req, sqe); case IORING_OP_MADVISE: return io_madvise_prep(req, sqe); case IORING_OP_OPENAT2: return io_openat2_prep(req, sqe); case IORING_OP_EPOLL_CTL: return io_epoll_ctl_prep(req, sqe); case IORING_OP_SPLICE: return io_splice_prep(req, sqe); case IORING_OP_PROVIDE_BUFFERS: return io_provide_buffers_prep(req, sqe); case IORING_OP_REMOVE_BUFFERS: return io_remove_buffers_prep(req, sqe); case IORING_OP_TEE: return io_tee_prep(req, sqe); case IORING_OP_SHUTDOWN: return io_shutdown_prep(req, sqe); case IORING_OP_RENAMEAT: return io_renameat_prep(req, sqe); case IORING_OP_UNLINKAT: return io_unlinkat_prep(req, sqe); } printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n", req->opcode); return-EINVAL; } static int io_req_defer_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (!sqe) return 0; if (io_alloc_async_data(req)) return -EAGAIN; return io_req_prep(req, sqe); } static u32 io_get_sequence(struct io_kiocb *req) { struct io_kiocb *pos; struct io_ring_ctx *ctx = req->ctx; u32 total_submitted, nr_reqs = 0; io_for_each_link(pos, req) nr_reqs++; total_submitted = ctx->cached_sq_head - ctx->cached_sq_dropped; return total_submitted - nr_reqs; } static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; struct io_defer_entry *de; int ret; u32 seq; /* Still need defer if there is pending req in defer list. */ if (likely(list_empty_careful(&ctx->defer_list) && !(req->flags & REQ_F_IO_DRAIN))) return 0; seq = io_get_sequence(req); /* Still a chance to pass the sequence check */ if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) return 0; if (!req->async_data) { ret = io_req_defer_prep(req, sqe); if (ret) return ret; } io_prep_async_link(req); de = kmalloc(sizeof(*de), GFP_KERNEL); if (!de) return -ENOMEM; spin_lock_irq(&ctx->completion_lock); if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) { spin_unlock_irq(&ctx->completion_lock); kfree(de); io_queue_async_work(req); return -EIOCBQUEUED; } trace_io_uring_defer(ctx, req, req->user_data); de->req = req; de->seq = seq; list_add_tail(&de->list, &ctx->defer_list); spin_unlock_irq(&ctx->completion_lock); return -EIOCBQUEUED; } static void __io_clean_op(struct io_kiocb *req) { if (req->flags & REQ_F_BUFFER_SELECTED) { switch (req->opcode) { case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: kfree((void *)(unsigned long)req->rw.addr); break; case IORING_OP_RECVMSG: case IORING_OP_RECV: kfree(req->sr_msg.kbuf); break; } req->flags &= ~REQ_F_BUFFER_SELECTED; } if (req->flags & REQ_F_NEED_CLEANUP) { switch (req->opcode) { case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: { struct io_async_rw *io = req->async_data; if (io->free_iovec) kfree(io->free_iovec); break; } case IORING_OP_RECVMSG: case IORING_OP_SENDMSG: { struct io_async_msghdr *io = req->async_data; kfree(io->free_iov); break; } case IORING_OP_SPLICE: case IORING_OP_TEE: io_put_file(req, req->splice.file_in, (req->splice.flags & SPLICE_F_FD_IN_FIXED)); break; case IORING_OP_OPENAT: case IORING_OP_OPENAT2: if (req->open.filename) putname(req->open.filename); break; case IORING_OP_RENAMEAT: putname(req->rename.oldpath); putname(req->rename.newpath); break; case IORING_OP_UNLINKAT: putname(req->unlink.filename); break; } req->flags &= ~REQ_F_NEED_CLEANUP; } } static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; int ret; switch (req->opcode) { case IORING_OP_NOP: ret = io_nop(req, issue_flags); break; case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: ret = io_read(req, issue_flags); break; case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: ret = io_write(req, issue_flags); break; case IORING_OP_FSYNC: ret = io_fsync(req, issue_flags); break; case IORING_OP_POLL_ADD: ret = io_poll_add(req, issue_flags); break; case IORING_OP_POLL_REMOVE: ret = io_poll_remove(req, issue_flags); break; case IORING_OP_SYNC_FILE_RANGE: ret = io_sync_file_range(req, issue_flags); break; case IORING_OP_SENDMSG: ret = io_sendmsg(req, issue_flags); break; case IORING_OP_SEND: ret = io_send(req, issue_flags); break; case IORING_OP_RECVMSG: ret = io_recvmsg(req, issue_flags); break; case IORING_OP_RECV: ret = io_recv(req, issue_flags); break; case IORING_OP_TIMEOUT: ret = io_timeout(req, issue_flags); break; case IORING_OP_TIMEOUT_REMOVE: ret = io_timeout_remove(req, issue_flags); break; case IORING_OP_ACCEPT: ret = io_accept(req, issue_flags); break; case IORING_OP_CONNECT: ret = io_connect(req, issue_flags); break; case IORING_OP_ASYNC_CANCEL: ret = io_async_cancel(req, issue_flags); break; case IORING_OP_FALLOCATE: ret = io_fallocate(req, issue_flags); break; case IORING_OP_OPENAT: ret = io_openat(req, issue_flags); break; case IORING_OP_CLOSE: ret = io_close(req, issue_flags); break; case IORING_OP_FILES_UPDATE: ret = io_files_update(req, issue_flags); break; case IORING_OP_STATX: ret = io_statx(req, issue_flags); break; case IORING_OP_FADVISE: ret = io_fadvise(req, issue_flags); break; case IORING_OP_MADVISE: ret = io_madvise(req, issue_flags); break; case IORING_OP_OPENAT2: ret = io_openat2(req, issue_flags); break; case IORING_OP_EPOLL_CTL: ret = io_epoll_ctl(req, issue_flags); break; case IORING_OP_SPLICE: ret = io_splice(req, issue_flags); break; case IORING_OP_PROVIDE_BUFFERS: ret = io_provide_buffers(req, issue_flags); break; case IORING_OP_REMOVE_BUFFERS: ret = io_remove_buffers(req, issue_flags); break; case IORING_OP_TEE: ret = io_tee(req, issue_flags); break; case IORING_OP_SHUTDOWN: ret = io_shutdown(req, issue_flags); break; case IORING_OP_RENAMEAT: ret = io_renameat(req, issue_flags); break; case IORING_OP_UNLINKAT: ret = io_unlinkat(req, issue_flags); break; default: ret = -EINVAL; break; } if (ret) return ret; /* If the op doesn't have a file, we're not polling for it */ if ((ctx->flags & IORING_SETUP_IOPOLL) && req->file) { const bool in_async = io_wq_current_is_worker(); /* workqueue context doesn't hold uring_lock, grab it now */ if (in_async) mutex_lock(&ctx->uring_lock); io_iopoll_req_issued(req, in_async); if (in_async) mutex_unlock(&ctx->uring_lock); } return 0; } static void io_wq_submit_work(struct io_wq_work *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct io_kiocb *timeout; int ret = 0; timeout = io_prep_linked_timeout(req); if (timeout) io_queue_linked_timeout(timeout); if (work->flags & IO_WQ_WORK_CANCEL) ret = -ECANCELED; if (!ret) { do { ret = io_issue_sqe(req, 0); /* * We can get EAGAIN for polled IO even though we're * forcing a sync submission from here, since we can't * wait for request slots on the block side. */ if (ret != -EAGAIN) break; cond_resched(); } while (1); } if (ret) { struct io_ring_ctx *lock_ctx = NULL; if (req->ctx->flags & IORING_SETUP_IOPOLL) lock_ctx = req->ctx; /* * io_iopoll_complete() does not hold completion_lock to * complete polled io, so here for polled io, we can not call * io_req_complete() directly, otherwise there maybe concurrent * access to cqring, defer_list, etc, which is not safe. Given * that io_iopoll_complete() is always called under uring_lock, * so here for polled io, we also get uring_lock to complete * it. */ if (lock_ctx) mutex_lock(&lock_ctx->uring_lock); req_set_fail_links(req); io_req_complete(req, ret); if (lock_ctx) mutex_unlock(&lock_ctx->uring_lock); } } static inline struct file *io_file_from_index(struct io_ring_ctx *ctx, int index) { struct fixed_rsrc_table *table; table = &ctx->file_data->table[index >> IORING_FILE_TABLE_SHIFT]; return table->files[index & IORING_FILE_TABLE_MASK]; } static struct file *io_file_get(struct io_submit_state *state, struct io_kiocb *req, int fd, bool fixed) { struct io_ring_ctx *ctx = req->ctx; struct file *file; if (fixed) { if (unlikely((unsigned int)fd >= ctx->nr_user_files)) return NULL; fd = array_index_nospec(fd, ctx->nr_user_files); file = io_file_from_index(ctx, fd); io_set_resource_node(req); } else { trace_io_uring_file_get(ctx, fd); file = __io_file_get(state, fd); } if (file && unlikely(file->f_op == &io_uring_fops)) io_req_track_inflight(req); return file; } static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *prev, *req = data->req; struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); prev = req->timeout.head; req->timeout.head = NULL; /* * We don't expect the list to be empty, that will only happen if we * race with the completion of the linked work. */ if (prev && refcount_inc_not_zero(&prev->refs)) io_remove_next_linked(prev); else prev = NULL; spin_unlock_irqrestore(&ctx->completion_lock, flags); if (prev) { req_set_fail_links(prev); io_async_find_and_cancel(ctx, req, prev->user_data, -ETIME); io_put_req_deferred(prev, 1); } else { io_req_complete_post(req, -ETIME, 0); io_put_req_deferred(req, 1); } return HRTIMER_NORESTART; } static void __io_queue_linked_timeout(struct io_kiocb *req) { /* * If the back reference is NULL, then our linked request finished * before we got a chance to setup the timer */ if (req->timeout.head) { struct io_timeout_data *data = req->async_data; data->timer.function = io_link_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); } } static void io_queue_linked_timeout(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; spin_lock_irq(&ctx->completion_lock); __io_queue_linked_timeout(req); spin_unlock_irq(&ctx->completion_lock); /* drop submission reference */ io_put_req(req); } static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req) { struct io_kiocb *nxt = req->link; if (!nxt || (req->flags & REQ_F_LINK_TIMEOUT) || nxt->opcode != IORING_OP_LINK_TIMEOUT) return NULL; nxt->timeout.head = req; nxt->flags |= REQ_F_LTIMEOUT_ACTIVE; req->flags |= REQ_F_LINK_TIMEOUT; return nxt; } static void __io_queue_sqe(struct io_kiocb *req) { struct io_kiocb *linked_timeout = io_prep_linked_timeout(req); const struct cred *old_creds = NULL; int ret; if ((req->flags & REQ_F_WORK_INITIALIZED) && (req->work.flags & IO_WQ_WORK_CREDS) && req->work.identity->creds != current_cred()) old_creds = override_creds(req->work.identity->creds); ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER); if (old_creds) revert_creds(old_creds); /* * We async punt it if the file wasn't marked NOWAIT, or if the file * doesn't support non-blocking read/write attempts */ if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) { if (!io_arm_poll_handler(req)) { /* * Queued up for async execution, worker will release * submit reference when the iocb is actually submitted. */ io_queue_async_work(req); } } else if (likely(!ret)) { /* drop submission reference */ if (req->flags & REQ_F_COMPLETE_INLINE) { struct io_ring_ctx *ctx = req->ctx; struct io_comp_state *cs = &ctx->submit_state.comp; cs->reqs[cs->nr++] = req; if (cs->nr == ARRAY_SIZE(cs->reqs)) io_submit_flush_completions(cs, ctx); } else { io_put_req(req); } } else { req_set_fail_links(req); io_put_req(req); io_req_complete(req, ret); } if (linked_timeout) io_queue_linked_timeout(linked_timeout); } static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe) { int ret; ret = io_req_defer(req, sqe); if (ret) { if (ret != -EIOCBQUEUED) { fail_req: req_set_fail_links(req); io_put_req(req); io_req_complete(req, ret); } } else if (req->flags & REQ_F_FORCE_ASYNC) { if (!req->async_data) { ret = io_req_defer_prep(req, sqe); if (unlikely(ret)) goto fail_req; } io_queue_async_work(req); } else { if (sqe) { ret = io_req_prep(req, sqe); if (unlikely(ret)) goto fail_req; } __io_queue_sqe(req); } } static inline void io_queue_link_head(struct io_kiocb *req) { if (unlikely(req->flags & REQ_F_FAIL_LINK)) { io_put_req(req); io_req_complete(req, -ECANCELED); } else io_queue_sqe(req, NULL); } struct io_submit_link { struct io_kiocb *head; struct io_kiocb *last; }; static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_submit_link *link) { struct io_ring_ctx *ctx = req->ctx; int ret; /* * If we already have a head request, queue this one for async * submittal once the head completes. If we don't have a head but * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be * submitted sync once the chain is complete. If none of those * conditions are true (normal request), then just queue it. */ if (link->head) { struct io_kiocb *head = link->head; /* * Taking sequential execution of a link, draining both sides * of the link also fullfils IOSQE_IO_DRAIN semantics for all * requests in the link. So, it drains the head and the * next after the link request. The last one is done via * drain_next flag to persist the effect across calls. */ if (req->flags & REQ_F_IO_DRAIN) { head->flags |= REQ_F_IO_DRAIN; ctx->drain_next = 1; } ret = io_req_defer_prep(req, sqe); if (unlikely(ret)) { /* fail even hard links since we don't submit */ head->flags |= REQ_F_FAIL_LINK; return ret; } trace_io_uring_link(ctx, req, head); link->last->link = req; link->last = req; /* last request of a link, enqueue the link */ if (!(req->flags & (REQ_F_LINK | REQ_F_HARDLINK))) { io_queue_link_head(head); link->head = NULL; } } else { if (unlikely(ctx->drain_next)) { req->flags |= REQ_F_IO_DRAIN; ctx->drain_next = 0; } if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) { ret = io_req_defer_prep(req, sqe); if (unlikely(ret)) req->flags |= REQ_F_FAIL_LINK; link->head = req; link->last = req; } else { io_queue_sqe(req, sqe); } } return 0; } /* * Batched submission is done, ensure local IO is flushed out. */ static void io_submit_state_end(struct io_submit_state *state, struct io_ring_ctx *ctx) { if (state->comp.nr) io_submit_flush_completions(&state->comp, ctx); if (state->plug_started) blk_finish_plug(&state->plug); io_state_file_put(state); } /* * Start submission side cache. */ static void io_submit_state_start(struct io_submit_state *state, unsigned int max_ios) { state->plug_started = false; state->ios_left = max_ios; } static void io_commit_sqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; /* * Ensure any loads from the SQEs are done at this point, * since once we write the new head, the application could * write new data to them. */ smp_store_release(&rings->sq.head, ctx->cached_sq_head); } /* * Fetch an sqe, if one is available. Note that sqe_ptr will point to memory * that is mapped by userspace. This means that care needs to be taken to * ensure that reads are stable, as we cannot rely on userspace always * being a good citizen. If members of the sqe are validated and then later * used, it's important that those reads are done through READ_ONCE() to * prevent a re-load down the line. */ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx) { u32 *sq_array = ctx->sq_array; unsigned head; /* * The cached sq head (or cq tail) serves two purposes: * * 1) allows us to batch the cost of updating the user visible * head updates. * 2) allows the kernel side to track the head on its own, even * though the application is the one updating it. */ head = READ_ONCE(sq_array[ctx->cached_sq_head++ & ctx->sq_mask]); if (likely(head < ctx->sq_entries)) return &ctx->sq_sqes[head]; /* drop invalid entries */ ctx->cached_sq_dropped++; WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped); return NULL; } /* * Check SQE restrictions (opcode and flags). * * Returns 'true' if SQE is allowed, 'false' otherwise. */ static inline bool io_check_restriction(struct io_ring_ctx *ctx, struct io_kiocb *req, unsigned int sqe_flags) { if (!ctx->restricted) return true; if (!test_bit(req->opcode, ctx->restrictions.sqe_op)) return false; if ((sqe_flags & ctx->restrictions.sqe_flags_required) != ctx->restrictions.sqe_flags_required) return false; if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed | ctx->restrictions.sqe_flags_required)) return false; return true; } #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \ IOSQE_IO_HARDLINK | IOSQE_ASYNC | \ IOSQE_BUFFER_SELECT) static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_submit_state *state; unsigned int sqe_flags; int id, ret = 0; req->opcode = READ_ONCE(sqe->opcode); /* same numerical values with corresponding REQ_F_*, safe to copy */ req->flags = sqe_flags = READ_ONCE(sqe->flags); req->user_data = READ_ONCE(sqe->user_data); req->async_data = NULL; req->file = NULL; req->ctx = ctx; req->link = NULL; req->fixed_rsrc_refs = NULL; /* one is dropped after submission, the other at completion */ refcount_set(&req->refs, 2); req->task = current; req->result = 0; /* enforce forwards compatibility on users */ if (unlikely(sqe_flags & ~SQE_VALID_FLAGS)) return -EINVAL; if (unlikely(req->opcode >= IORING_OP_LAST)) return -EINVAL; if (unlikely(io_sq_thread_acquire_mm_files(ctx, req))) return -EFAULT; if (unlikely(!io_check_restriction(ctx, req, sqe_flags))) return -EACCES; if ((sqe_flags & IOSQE_BUFFER_SELECT) && !io_op_defs[req->opcode].buffer_select) return -EOPNOTSUPP; id = READ_ONCE(sqe->personality); if (id) { struct io_identity *iod; iod = idr_find(&ctx->personality_idr, id); if (unlikely(!iod)) return -EINVAL; refcount_inc(&iod->count); __io_req_init_async(req); get_cred(iod->creds); req->work.identity = iod; req->work.flags |= IO_WQ_WORK_CREDS; } state = &ctx->submit_state; /* * Plug now if we have more than 1 IO left after this, and the target * is potentially a read/write to block based storage. */ if (!state->plug_started && state->ios_left > 1 && io_op_defs[req->opcode].plug) { blk_start_plug(&state->plug); state->plug_started = true; } if (io_op_defs[req->opcode].needs_file) { bool fixed = req->flags & REQ_F_FIXED_FILE; req->file = io_file_get(state, req, READ_ONCE(sqe->fd), fixed); if (unlikely(!req->file)) ret = -EBADF; } state->ios_left--; return ret; } static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr) { struct io_submit_link link; int submitted = 0; /* if we have a backlog and couldn't flush it all, return BUSY */ if (test_bit(0, &ctx->sq_check_overflow)) { if (!__io_cqring_overflow_flush(ctx, false, NULL, NULL)) return -EBUSY; } /* make sure SQ entry isn't read before tail */ nr = min3(nr, ctx->sq_entries, io_sqring_entries(ctx)); if (!percpu_ref_tryget_many(&ctx->refs, nr)) return -EAGAIN; percpu_counter_add(¤t->io_uring->inflight, nr); refcount_add(nr, ¤t->usage); io_submit_state_start(&ctx->submit_state, nr); link.head = NULL; while (submitted < nr) { const struct io_uring_sqe *sqe; struct io_kiocb *req; int err; req = io_alloc_req(ctx); if (unlikely(!req)) { if (!submitted) submitted = -EAGAIN; break; } sqe = io_get_sqe(ctx); if (unlikely(!sqe)) { kmem_cache_free(req_cachep, req); break; } /* will complete beyond this point, count as submitted */ submitted++; err = io_init_req(ctx, req, sqe); if (unlikely(err)) { fail_req: io_put_req(req); io_req_complete(req, err); break; } trace_io_uring_submit_sqe(ctx, req->opcode, req->user_data, true, ctx->flags & IORING_SETUP_SQPOLL); err = io_submit_sqe(req, sqe, &link); if (err) goto fail_req; } if (unlikely(submitted != nr)) { int ref_used = (submitted == -EAGAIN) ? 0 : submitted; struct io_uring_task *tctx = current->io_uring; int unused = nr - ref_used; percpu_ref_put_many(&ctx->refs, unused); percpu_counter_sub(&tctx->inflight, unused); put_task_struct_many(current, unused); } if (link.head) io_queue_link_head(link.head); io_submit_state_end(&ctx->submit_state, ctx); /* Commit SQ ring head once we've consumed and submitted all SQEs */ io_commit_sqring(ctx); return submitted; } static inline void io_ring_set_wakeup_flag(struct io_ring_ctx *ctx) { /* Tell userspace we may need a wakeup call */ spin_lock_irq(&ctx->completion_lock); ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP; spin_unlock_irq(&ctx->completion_lock); } static inline void io_ring_clear_wakeup_flag(struct io_ring_ctx *ctx) { spin_lock_irq(&ctx->completion_lock); ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP; spin_unlock_irq(&ctx->completion_lock); } static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries) { unsigned int to_submit; int ret = 0; to_submit = io_sqring_entries(ctx); /* if we're handling multiple rings, cap submit size for fairness */ if (cap_entries && to_submit > 8) to_submit = 8; if (!list_empty(&ctx->iopoll_list) || to_submit) { unsigned nr_events = 0; mutex_lock(&ctx->uring_lock); if (!list_empty(&ctx->iopoll_list)) io_do_iopoll(ctx, &nr_events, 0); if (to_submit && !ctx->sqo_dead && likely(!percpu_ref_is_dying(&ctx->refs))) ret = io_submit_sqes(ctx, to_submit); mutex_unlock(&ctx->uring_lock); } if (!io_sqring_full(ctx) && wq_has_sleeper(&ctx->sqo_sq_wait)) wake_up(&ctx->sqo_sq_wait); return ret; } static void io_sqd_update_thread_idle(struct io_sq_data *sqd) { struct io_ring_ctx *ctx; unsigned sq_thread_idle = 0; list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { if (sq_thread_idle < ctx->sq_thread_idle) sq_thread_idle = ctx->sq_thread_idle; } sqd->sq_thread_idle = sq_thread_idle; } static void io_sqd_init_new(struct io_sq_data *sqd) { struct io_ring_ctx *ctx; while (!list_empty(&sqd->ctx_new_list)) { ctx = list_first_entry(&sqd->ctx_new_list, struct io_ring_ctx, sqd_list); list_move_tail(&ctx->sqd_list, &sqd->ctx_list); complete(&ctx->sq_thread_comp); } io_sqd_update_thread_idle(sqd); } static int io_sq_thread(void *data) { struct cgroup_subsys_state *cur_css = NULL; struct files_struct *old_files = current->files; struct nsproxy *old_nsproxy = current->nsproxy; const struct cred *old_cred = NULL; struct io_sq_data *sqd = data; struct io_ring_ctx *ctx; unsigned long timeout = 0; DEFINE_WAIT(wait); task_lock(current); current->files = NULL; current->nsproxy = NULL; task_unlock(current); while (!kthread_should_stop()) { int ret; bool cap_entries, sqt_spin, needs_sched; /* * Any changes to the sqd lists are synchronized through the * kthread parking. This synchronizes the thread vs users, * the users are synchronized on the sqd->ctx_lock. */ if (kthread_should_park()) { kthread_parkme(); /* * When sq thread is unparked, in case the previous park operation * comes from io_put_sq_data(), which means that sq thread is going * to be stopped, so here needs to have a check. */ if (kthread_should_stop()) break; } if (unlikely(!list_empty(&sqd->ctx_new_list))) { io_sqd_init_new(sqd); timeout = jiffies + sqd->sq_thread_idle; } sqt_spin = false; cap_entries = !list_is_singular(&sqd->ctx_list); list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { if (current->cred != ctx->creds) { if (old_cred) revert_creds(old_cred); old_cred = override_creds(ctx->creds); } io_sq_thread_associate_blkcg(ctx, &cur_css); #ifdef CONFIG_AUDIT current->loginuid = ctx->loginuid; current->sessionid = ctx->sessionid; #endif ret = __io_sq_thread(ctx, cap_entries); if (!sqt_spin && (ret > 0 || !list_empty(&ctx->iopoll_list))) sqt_spin = true; io_sq_thread_drop_mm_files(); } if (sqt_spin || !time_after(jiffies, timeout)) { io_run_task_work(); io_sq_thread_drop_mm_files(); cond_resched(); if (sqt_spin) timeout = jiffies + sqd->sq_thread_idle; continue; } needs_sched = true; prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE); list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { if ((ctx->flags & IORING_SETUP_IOPOLL) && !list_empty_careful(&ctx->iopoll_list)) { needs_sched = false; break; } if (io_sqring_entries(ctx)) { needs_sched = false; break; } } if (needs_sched && !kthread_should_park()) { list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) io_ring_set_wakeup_flag(ctx); schedule(); list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) io_ring_clear_wakeup_flag(ctx); } finish_wait(&sqd->wait, &wait); timeout = jiffies + sqd->sq_thread_idle; } io_run_task_work(); io_sq_thread_drop_mm_files(); if (cur_css) io_sq_thread_unassociate_blkcg(); if (old_cred) revert_creds(old_cred); task_lock(current); current->files = old_files; current->nsproxy = old_nsproxy; task_unlock(current); kthread_parkme(); return 0; } struct io_wait_queue { struct wait_queue_entry wq; struct io_ring_ctx *ctx; unsigned to_wait; unsigned nr_timeouts; }; static inline bool io_should_wake(struct io_wait_queue *iowq) { struct io_ring_ctx *ctx = iowq->ctx; /* * Wake up if we have enough events, or if a timeout occurred since we * started waiting. For timeouts, we always want to return to userspace, * regardless of event count. */ return io_cqring_events(ctx) >= iowq->to_wait || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts; } static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode, int wake_flags, void *key) { struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq); /* * Cannot safely flush overflowed CQEs from here, ensure we wake up * the task, and the next invocation will do it. */ if (io_should_wake(iowq) || test_bit(0, &iowq->ctx->cq_check_overflow)) return autoremove_wake_function(curr, mode, wake_flags, key); return -1; } static int io_run_task_work_sig(void) { if (io_run_task_work()) return 1; if (!signal_pending(current)) return 0; if (test_tsk_thread_flag(current, TIF_NOTIFY_SIGNAL)) return -ERESTARTSYS; return -EINTR; } /* when returns >0, the caller should retry */ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx, struct io_wait_queue *iowq, signed long *timeout) { int ret; /* make sure we run task_work before checking for signals */ ret = io_run_task_work_sig(); if (ret || io_should_wake(iowq)) return ret; /* let the caller flush overflows, retry */ if (test_bit(0, &ctx->cq_check_overflow)) return 1; *timeout = schedule_timeout(*timeout); return !*timeout ? -ETIME : 1; } /* * Wait until events become available, if we don't already have some. The * application must reap them itself, as they reside on the shared cq ring. */ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, const sigset_t __user *sig, size_t sigsz, struct __kernel_timespec __user *uts) { struct io_wait_queue iowq = { .wq = { .private = current, .func = io_wake_function, .entry = LIST_HEAD_INIT(iowq.wq.entry), }, .ctx = ctx, .to_wait = min_events, }; struct io_rings *rings = ctx->rings; signed long timeout = MAX_SCHEDULE_TIMEOUT; int ret; do { io_cqring_overflow_flush(ctx, false, NULL, NULL); if (io_cqring_events(ctx) >= min_events) return 0; if (!io_run_task_work()) break; } while (1); if (sig) { #ifdef CONFIG_COMPAT if (in_compat_syscall()) ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig, sigsz); else #endif ret = set_user_sigmask(sig, sigsz); if (ret) return ret; } if (uts) { struct timespec64 ts; if (get_timespec64(&ts, uts)) return -EFAULT; timeout = timespec64_to_jiffies(&ts); } iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts); trace_io_uring_cqring_wait(ctx, min_events); do { io_cqring_overflow_flush(ctx, false, NULL, NULL); prepare_to_wait_exclusive(&ctx->wait, &iowq.wq, TASK_INTERRUPTIBLE); ret = io_cqring_wait_schedule(ctx, &iowq, &timeout); finish_wait(&ctx->wait, &iowq.wq); } while (ret > 0); restore_saved_sigmask_unless(ret == -EINTR); return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0; } static void __io_sqe_files_unregister(struct io_ring_ctx *ctx) { #if defined(CONFIG_UNIX) if (ctx->ring_sock) { struct sock *sock = ctx->ring_sock->sk; struct sk_buff *skb; while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) kfree_skb(skb); } #else int i; for (i = 0; i < ctx->nr_user_files; i++) { struct file *file; file = io_file_from_index(ctx, i); if (file) fput(file); } #endif } static void io_rsrc_data_ref_zero(struct percpu_ref *ref) { struct fixed_rsrc_data *data; data = container_of(ref, struct fixed_rsrc_data, refs); complete(&data->done); } static inline void io_rsrc_ref_lock(struct io_ring_ctx *ctx) { spin_lock_bh(&ctx->rsrc_ref_lock); } static inline void io_rsrc_ref_unlock(struct io_ring_ctx *ctx) { spin_unlock_bh(&ctx->rsrc_ref_lock); } static void io_sqe_rsrc_set_node(struct io_ring_ctx *ctx, struct fixed_rsrc_data *rsrc_data, struct fixed_rsrc_ref_node *ref_node) { io_rsrc_ref_lock(ctx); rsrc_data->node = ref_node; list_add_tail(&ref_node->node, &ctx->rsrc_ref_list); io_rsrc_ref_unlock(ctx); percpu_ref_get(&rsrc_data->refs); } static int io_rsrc_ref_quiesce(struct fixed_rsrc_data *data, struct io_ring_ctx *ctx, struct fixed_rsrc_ref_node *backup_node) { struct fixed_rsrc_ref_node *ref_node; int ret; io_rsrc_ref_lock(ctx); ref_node = data->node; io_rsrc_ref_unlock(ctx); if (ref_node) percpu_ref_kill(&ref_node->refs); percpu_ref_kill(&data->refs); /* wait for all refs nodes to complete */ flush_delayed_work(&ctx->rsrc_put_work); do { ret = wait_for_completion_interruptible(&data->done); if (!ret) break; ret = io_run_task_work_sig(); if (ret < 0) { percpu_ref_resurrect(&data->refs); reinit_completion(&data->done); io_sqe_rsrc_set_node(ctx, data, backup_node); return ret; } } while (1); destroy_fixed_rsrc_ref_node(backup_node); return 0; } static struct fixed_rsrc_data *alloc_fixed_rsrc_data(struct io_ring_ctx *ctx) { struct fixed_rsrc_data *data; data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return NULL; if (percpu_ref_init(&data->refs, io_rsrc_data_ref_zero, PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) { kfree(data); return NULL; } data->ctx = ctx; init_completion(&data->done); return data; } static void free_fixed_rsrc_data(struct fixed_rsrc_data *data) { percpu_ref_exit(&data->refs); kfree(data->table); kfree(data); } static int io_sqe_files_unregister(struct io_ring_ctx *ctx) { struct fixed_rsrc_data *data = ctx->file_data; struct fixed_rsrc_ref_node *backup_node; unsigned nr_tables, i; int ret; if (!data) return -ENXIO; backup_node = alloc_fixed_rsrc_ref_node(ctx); if (!backup_node) return -ENOMEM; init_fixed_file_ref_node(ctx, backup_node); ret = io_rsrc_ref_quiesce(data, ctx, backup_node); if (ret) return ret; __io_sqe_files_unregister(ctx); nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE); for (i = 0; i < nr_tables; i++) kfree(data->table[i].files); free_fixed_rsrc_data(data); ctx->file_data = NULL; ctx->nr_user_files = 0; return 0; } static void io_put_sq_data(struct io_sq_data *sqd) { if (refcount_dec_and_test(&sqd->refs)) { /* * The park is a bit of a work-around, without it we get * warning spews on shutdown with SQPOLL set and affinity * set to a single CPU. */ if (sqd->thread) { kthread_park(sqd->thread); kthread_stop(sqd->thread); } kfree(sqd); } } static struct io_sq_data *io_attach_sq_data(struct io_uring_params *p) { struct io_ring_ctx *ctx_attach; struct io_sq_data *sqd; struct fd f; f = fdget(p->wq_fd); if (!f.file) return ERR_PTR(-ENXIO); if (f.file->f_op != &io_uring_fops) { fdput(f); return ERR_PTR(-EINVAL); } ctx_attach = f.file->private_data; sqd = ctx_attach->sq_data; if (!sqd) { fdput(f); return ERR_PTR(-EINVAL); } refcount_inc(&sqd->refs); fdput(f); return sqd; } static struct io_sq_data *io_get_sq_data(struct io_uring_params *p) { struct io_sq_data *sqd; if (p->flags & IORING_SETUP_ATTACH_WQ) return io_attach_sq_data(p); sqd = kzalloc(sizeof(*sqd), GFP_KERNEL); if (!sqd) return ERR_PTR(-ENOMEM); refcount_set(&sqd->refs, 1); INIT_LIST_HEAD(&sqd->ctx_list); INIT_LIST_HEAD(&sqd->ctx_new_list); mutex_init(&sqd->ctx_lock); mutex_init(&sqd->lock); init_waitqueue_head(&sqd->wait); return sqd; } static void io_sq_thread_unpark(struct io_sq_data *sqd) __releases(&sqd->lock) { if (!sqd->thread) return; kthread_unpark(sqd->thread); mutex_unlock(&sqd->lock); } static void io_sq_thread_park(struct io_sq_data *sqd) __acquires(&sqd->lock) { if (!sqd->thread) return; mutex_lock(&sqd->lock); kthread_park(sqd->thread); } static void io_sq_thread_stop(struct io_ring_ctx *ctx) { struct io_sq_data *sqd = ctx->sq_data; if (sqd) { if (sqd->thread) { /* * We may arrive here from the error branch in * io_sq_offload_create() where the kthread is created * without being waked up, thus wake it up now to make * sure the wait will complete. */ wake_up_process(sqd->thread); wait_for_completion(&ctx->sq_thread_comp); io_sq_thread_park(sqd); } mutex_lock(&sqd->ctx_lock); list_del(&ctx->sqd_list); io_sqd_update_thread_idle(sqd); mutex_unlock(&sqd->ctx_lock); if (sqd->thread) io_sq_thread_unpark(sqd); io_put_sq_data(sqd); ctx->sq_data = NULL; } } static void io_finish_async(struct io_ring_ctx *ctx) { io_sq_thread_stop(ctx); if (ctx->io_wq) { io_wq_destroy(ctx->io_wq); ctx->io_wq = NULL; } } #if defined(CONFIG_UNIX) /* * Ensure the UNIX gc is aware of our file set, so we are certain that * the io_uring can be safely unregistered on process exit, even if we have * loops in the file referencing. */ static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset) { struct sock *sk = ctx->ring_sock->sk; struct scm_fp_list *fpl; struct sk_buff *skb; int i, nr_files; fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); if (!fpl) return -ENOMEM; skb = alloc_skb(0, GFP_KERNEL); if (!skb) { kfree(fpl); return -ENOMEM; } skb->sk = sk; nr_files = 0; fpl->user = get_uid(ctx->user); for (i = 0; i < nr; i++) { struct file *file = io_file_from_index(ctx, i + offset); if (!file) continue; fpl->fp[nr_files] = get_file(file); unix_inflight(fpl->user, fpl->fp[nr_files]); nr_files++; } if (nr_files) { fpl->max = SCM_MAX_FD; fpl->count = nr_files; UNIXCB(skb).fp = fpl; skb->destructor = unix_destruct_scm; refcount_add(skb->truesize, &sk->sk_wmem_alloc); skb_queue_head(&sk->sk_receive_queue, skb); for (i = 0; i < nr_files; i++) fput(fpl->fp[i]); } else { kfree_skb(skb); kfree(fpl); } return 0; } /* * If UNIX sockets are enabled, fd passing can cause a reference cycle which * causes regular reference counting to break down. We rely on the UNIX * garbage collection to take care of this problem for us. */ static int io_sqe_files_scm(struct io_ring_ctx *ctx) { unsigned left, total; int ret = 0; total = 0; left = ctx->nr_user_files; while (left) { unsigned this_files = min_t(unsigned, left, SCM_MAX_FD); ret = __io_sqe_files_scm(ctx, this_files, total); if (ret) break; left -= this_files; total += this_files; } if (!ret) return 0; while (total < ctx->nr_user_files) { struct file *file = io_file_from_index(ctx, total); if (file) fput(file); total++; } return ret; } #else static int io_sqe_files_scm(struct io_ring_ctx *ctx) { return 0; } #endif static int io_sqe_alloc_file_tables(struct fixed_rsrc_data *file_data, unsigned nr_tables, unsigned nr_files) { int i; for (i = 0; i < nr_tables; i++) { struct fixed_rsrc_table *table = &file_data->table[i]; unsigned this_files; this_files = min(nr_files, IORING_MAX_FILES_TABLE); table->files = kcalloc(this_files, sizeof(struct file *), GFP_KERNEL); if (!table->files) break; nr_files -= this_files; } if (i == nr_tables) return 0; for (i = 0; i < nr_tables; i++) { struct fixed_rsrc_table *table = &file_data->table[i]; kfree(table->files); } return 1; } static void io_ring_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) { struct file *file = prsrc->file; #if defined(CONFIG_UNIX) struct sock *sock = ctx->ring_sock->sk; struct sk_buff_head list, *head = &sock->sk_receive_queue; struct sk_buff *skb; int i; __skb_queue_head_init(&list); /* * Find the skb that holds this file in its SCM_RIGHTS. When found, * remove this entry and rearrange the file array. */ skb = skb_dequeue(head); while (skb) { struct scm_fp_list *fp; fp = UNIXCB(skb).fp; for (i = 0; i < fp->count; i++) { int left; if (fp->fp[i] != file) continue; unix_notinflight(fp->user, fp->fp[i]); left = fp->count - 1 - i; if (left) { memmove(&fp->fp[i], &fp->fp[i + 1], left * sizeof(struct file *)); } fp->count--; if (!fp->count) { kfree_skb(skb); skb = NULL; } else { __skb_queue_tail(&list, skb); } fput(file); file = NULL; break; } if (!file) break; __skb_queue_tail(&list, skb); skb = skb_dequeue(head); } if (skb_peek(&list)) { spin_lock_irq(&head->lock); while ((skb = __skb_dequeue(&list)) != NULL) __skb_queue_tail(head, skb); spin_unlock_irq(&head->lock); } #else fput(file); #endif } static void __io_rsrc_put_work(struct fixed_rsrc_ref_node *ref_node) { struct fixed_rsrc_data *rsrc_data = ref_node->rsrc_data; struct io_ring_ctx *ctx = rsrc_data->ctx; struct io_rsrc_put *prsrc, *tmp; list_for_each_entry_safe(prsrc, tmp, &ref_node->rsrc_list, list) { list_del(&prsrc->list); ref_node->rsrc_put(ctx, prsrc); kfree(prsrc); } percpu_ref_exit(&ref_node->refs); kfree(ref_node); percpu_ref_put(&rsrc_data->refs); } static void io_rsrc_put_work(struct work_struct *work) { struct io_ring_ctx *ctx; struct llist_node *node; ctx = container_of(work, struct io_ring_ctx, rsrc_put_work.work); node = llist_del_all(&ctx->rsrc_put_llist); while (node) { struct fixed_rsrc_ref_node *ref_node; struct llist_node *next = node->next; ref_node = llist_entry(node, struct fixed_rsrc_ref_node, llist); __io_rsrc_put_work(ref_node); node = next; } } static struct file **io_fixed_file_slot(struct fixed_rsrc_data *file_data, unsigned i) { struct fixed_rsrc_table *table; table = &file_data->table[i >> IORING_FILE_TABLE_SHIFT]; return &table->files[i & IORING_FILE_TABLE_MASK]; } static void io_rsrc_node_ref_zero(struct percpu_ref *ref) { struct fixed_rsrc_ref_node *ref_node; struct fixed_rsrc_data *data; struct io_ring_ctx *ctx; bool first_add = false; int delay = HZ; ref_node = container_of(ref, struct fixed_rsrc_ref_node, refs); data = ref_node->rsrc_data; ctx = data->ctx; io_rsrc_ref_lock(ctx); ref_node->done = true; while (!list_empty(&ctx->rsrc_ref_list)) { ref_node = list_first_entry(&ctx->rsrc_ref_list, struct fixed_rsrc_ref_node, node); /* recycle ref nodes in order */ if (!ref_node->done) break; list_del(&ref_node->node); first_add |= llist_add(&ref_node->llist, &ctx->rsrc_put_llist); } io_rsrc_ref_unlock(ctx); if (percpu_ref_is_dying(&data->refs)) delay = 0; if (!delay) mod_delayed_work(system_wq, &ctx->rsrc_put_work, 0); else if (first_add) queue_delayed_work(system_wq, &ctx->rsrc_put_work, delay); } static struct fixed_rsrc_ref_node *alloc_fixed_rsrc_ref_node( struct io_ring_ctx *ctx) { struct fixed_rsrc_ref_node *ref_node; ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); if (!ref_node) return NULL; if (percpu_ref_init(&ref_node->refs, io_rsrc_node_ref_zero, 0, GFP_KERNEL)) { kfree(ref_node); return NULL; } INIT_LIST_HEAD(&ref_node->node); INIT_LIST_HEAD(&ref_node->rsrc_list); ref_node->done = false; return ref_node; } static void init_fixed_file_ref_node(struct io_ring_ctx *ctx, struct fixed_rsrc_ref_node *ref_node) { ref_node->rsrc_data = ctx->file_data; ref_node->rsrc_put = io_ring_file_put; } static void destroy_fixed_rsrc_ref_node(struct fixed_rsrc_ref_node *ref_node) { percpu_ref_exit(&ref_node->refs); kfree(ref_node); } static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { __s32 __user *fds = (__s32 __user *) arg; unsigned nr_tables, i; struct file *file; int fd, ret = -ENOMEM; struct fixed_rsrc_ref_node *ref_node; struct fixed_rsrc_data *file_data; if (ctx->file_data) return -EBUSY; if (!nr_args) return -EINVAL; if (nr_args > IORING_MAX_FIXED_FILES) return -EMFILE; file_data = alloc_fixed_rsrc_data(ctx); if (!file_data) return -ENOMEM; ctx->file_data = file_data; nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE); file_data->table = kcalloc(nr_tables, sizeof(*file_data->table), GFP_KERNEL); if (!file_data->table) goto out_free; if (io_sqe_alloc_file_tables(file_data, nr_tables, nr_args)) goto out_free; for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { if (copy_from_user(&fd, &fds[i], sizeof(fd))) { ret = -EFAULT; goto out_fput; } /* allow sparse sets */ if (fd == -1) continue; file = fget(fd); ret = -EBADF; if (!file) goto out_fput; /* * Don't allow io_uring instances to be registered. If UNIX * isn't enabled, then this causes a reference cycle and this * instance can never get freed. If UNIX is enabled we'll * handle it just fine, but there's still no point in allowing * a ring fd as it doesn't support regular read/write anyway. */ if (file->f_op == &io_uring_fops) { fput(file); goto out_fput; } *io_fixed_file_slot(file_data, i) = file; } ret = io_sqe_files_scm(ctx); if (ret) { io_sqe_files_unregister(ctx); return ret; } ref_node = alloc_fixed_rsrc_ref_node(ctx); if (!ref_node) { io_sqe_files_unregister(ctx); return -ENOMEM; } init_fixed_file_ref_node(ctx, ref_node); io_sqe_rsrc_set_node(ctx, file_data, ref_node); return ret; out_fput: for (i = 0; i < ctx->nr_user_files; i++) { file = io_file_from_index(ctx, i); if (file) fput(file); } for (i = 0; i < nr_tables; i++) kfree(file_data->table[i].files); ctx->nr_user_files = 0; out_free: free_fixed_rsrc_data(ctx->file_data); ctx->file_data = NULL; return ret; } static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file, int index) { #if defined(CONFIG_UNIX) struct sock *sock = ctx->ring_sock->sk; struct sk_buff_head *head = &sock->sk_receive_queue; struct sk_buff *skb; /* * See if we can merge this file into an existing skb SCM_RIGHTS * file set. If there's no room, fall back to allocating a new skb * and filling it in. */ spin_lock_irq(&head->lock); skb = skb_peek(head); if (skb) { struct scm_fp_list *fpl = UNIXCB(skb).fp; if (fpl->count < SCM_MAX_FD) { __skb_unlink(skb, head); spin_unlock_irq(&head->lock); fpl->fp[fpl->count] = get_file(file); unix_inflight(fpl->user, fpl->fp[fpl->count]); fpl->count++; spin_lock_irq(&head->lock); __skb_queue_head(head, skb); } else { skb = NULL; } } spin_unlock_irq(&head->lock); if (skb) { fput(file); return 0; } return __io_sqe_files_scm(ctx, 1, index); #else return 0; #endif } static int io_queue_rsrc_removal(struct fixed_rsrc_data *data, void *rsrc) { struct io_rsrc_put *prsrc; struct fixed_rsrc_ref_node *ref_node = data->node; prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL); if (!prsrc) return -ENOMEM; prsrc->rsrc = rsrc; list_add(&prsrc->list, &ref_node->rsrc_list); return 0; } static inline int io_queue_file_removal(struct fixed_rsrc_data *data, struct file *file) { return io_queue_rsrc_removal(data, (void *)file); } static int __io_sqe_files_update(struct io_ring_ctx *ctx, struct io_uring_rsrc_update *up, unsigned nr_args) { struct fixed_rsrc_data *data = ctx->file_data; struct fixed_rsrc_ref_node *ref_node; struct file *file, **file_slot; __s32 __user *fds; int fd, i, err; __u32 done; bool needs_switch = false; if (check_add_overflow(up->offset, nr_args, &done)) return -EOVERFLOW; if (done > ctx->nr_user_files) return -EINVAL; ref_node = alloc_fixed_rsrc_ref_node(ctx); if (!ref_node) return -ENOMEM; init_fixed_file_ref_node(ctx, ref_node); fds = u64_to_user_ptr(up->data); for (done = 0; done < nr_args; done++) { err = 0; if (copy_from_user(&fd, &fds[done], sizeof(fd))) { err = -EFAULT; break; } if (fd == IORING_REGISTER_FILES_SKIP) continue; i = array_index_nospec(up->offset + done, ctx->nr_user_files); file_slot = io_fixed_file_slot(ctx->file_data, i); if (*file_slot) { err = io_queue_file_removal(data, *file_slot); if (err) break; *file_slot = NULL; needs_switch = true; } if (fd != -1) { file = fget(fd); if (!file) { err = -EBADF; break; } /* * Don't allow io_uring instances to be registered. If * UNIX isn't enabled, then this causes a reference * cycle and this instance can never get freed. If UNIX * is enabled we'll handle it just fine, but there's * still no point in allowing a ring fd as it doesn't * support regular read/write anyway. */ if (file->f_op == &io_uring_fops) { fput(file); err = -EBADF; break; } *file_slot = file; err = io_sqe_file_register(ctx, file, i); if (err) { *file_slot = NULL; fput(file); break; } } } if (needs_switch) { percpu_ref_kill(&data->node->refs); io_sqe_rsrc_set_node(ctx, data, ref_node); } else destroy_fixed_rsrc_ref_node(ref_node); return done ? done : err; } static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct io_uring_rsrc_update up; if (!ctx->file_data) return -ENXIO; if (!nr_args) return -EINVAL; if (copy_from_user(&up, arg, sizeof(up))) return -EFAULT; if (up.resv) return -EINVAL; return __io_sqe_files_update(ctx, &up, nr_args); } static struct io_wq_work *io_free_work(struct io_wq_work *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); req = io_put_req_find_next(req); return req ? &req->work : NULL; } static int io_init_wq_offload(struct io_ring_ctx *ctx, struct io_uring_params *p) { struct io_wq_data data; struct fd f; struct io_ring_ctx *ctx_attach; unsigned int concurrency; int ret = 0; data.user = ctx->user; data.free_work = io_free_work; data.do_work = io_wq_submit_work; if (!(p->flags & IORING_SETUP_ATTACH_WQ)) { /* Do QD, or 4 * CPUS, whatever is smallest */ concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); ctx->io_wq = io_wq_create(concurrency, &data); if (IS_ERR(ctx->io_wq)) { ret = PTR_ERR(ctx->io_wq); ctx->io_wq = NULL; } return ret; } f = fdget(p->wq_fd); if (!f.file) return -EBADF; if (f.file->f_op != &io_uring_fops) { ret = -EINVAL; goto out_fput; } ctx_attach = f.file->private_data; /* @io_wq is protected by holding the fd */ if (!io_wq_get(ctx_attach->io_wq, &data)) { ret = -EINVAL; goto out_fput; } ctx->io_wq = ctx_attach->io_wq; out_fput: fdput(f); return ret; } static int io_uring_alloc_task_context(struct task_struct *task) { struct io_uring_task *tctx; int ret; tctx = kmalloc(sizeof(*tctx), GFP_KERNEL); if (unlikely(!tctx)) return -ENOMEM; ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL); if (unlikely(ret)) { kfree(tctx); return ret; } xa_init(&tctx->xa); init_waitqueue_head(&tctx->wait); tctx->last = NULL; atomic_set(&tctx->in_idle, 0); tctx->sqpoll = false; io_init_identity(&tctx->__identity); tctx->identity = &tctx->__identity; task->io_uring = tctx; spin_lock_init(&tctx->task_lock); INIT_WQ_LIST(&tctx->task_list); tctx->task_state = 0; init_task_work(&tctx->task_work, tctx_task_work); return 0; } void __io_uring_free(struct task_struct *tsk) { struct io_uring_task *tctx = tsk->io_uring; WARN_ON_ONCE(!xa_empty(&tctx->xa)); WARN_ON_ONCE(refcount_read(&tctx->identity->count) != 1); if (tctx->identity != &tctx->__identity) kfree(tctx->identity); percpu_counter_destroy(&tctx->inflight); kfree(tctx); tsk->io_uring = NULL; } static int io_sq_offload_create(struct io_ring_ctx *ctx, struct io_uring_params *p) { int ret; if (ctx->flags & IORING_SETUP_SQPOLL) { struct io_sq_data *sqd; ret = -EPERM; if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_NICE)) goto err; sqd = io_get_sq_data(p); if (IS_ERR(sqd)) { ret = PTR_ERR(sqd); goto err; } ctx->sq_data = sqd; io_sq_thread_park(sqd); mutex_lock(&sqd->ctx_lock); list_add(&ctx->sqd_list, &sqd->ctx_new_list); mutex_unlock(&sqd->ctx_lock); io_sq_thread_unpark(sqd); ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle); if (!ctx->sq_thread_idle) ctx->sq_thread_idle = HZ; if (sqd->thread) goto done; if (p->flags & IORING_SETUP_SQ_AFF) { int cpu = p->sq_thread_cpu; ret = -EINVAL; if (cpu >= nr_cpu_ids) goto err; if (!cpu_online(cpu)) goto err; sqd->thread = kthread_create_on_cpu(io_sq_thread, sqd, cpu, "io_uring-sq"); } else { sqd->thread = kthread_create(io_sq_thread, sqd, "io_uring-sq"); } if (IS_ERR(sqd->thread)) { ret = PTR_ERR(sqd->thread); sqd->thread = NULL; goto err; } ret = io_uring_alloc_task_context(sqd->thread); if (ret) goto err; } else if (p->flags & IORING_SETUP_SQ_AFF) { /* Can't have SQ_AFF without SQPOLL */ ret = -EINVAL; goto err; } done: ret = io_init_wq_offload(ctx, p); if (ret) goto err; return 0; err: io_finish_async(ctx); return ret; } static void io_sq_offload_start(struct io_ring_ctx *ctx) { struct io_sq_data *sqd = ctx->sq_data; if ((ctx->flags & IORING_SETUP_SQPOLL) && sqd->thread) wake_up_process(sqd->thread); } static inline void __io_unaccount_mem(struct user_struct *user, unsigned long nr_pages) { atomic_long_sub(nr_pages, &user->locked_vm); } static inline int __io_account_mem(struct user_struct *user, unsigned long nr_pages) { unsigned long page_limit, cur_pages, new_pages; /* Don't allow more pages than we can safely lock */ page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; do { cur_pages = atomic_long_read(&user->locked_vm); new_pages = cur_pages + nr_pages; if (new_pages > page_limit) return -ENOMEM; } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages, new_pages) != cur_pages); return 0; } static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) { if (ctx->limit_mem) __io_unaccount_mem(ctx->user, nr_pages); if (ctx->mm_account) atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm); } static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) { int ret; if (ctx->limit_mem) { ret = __io_account_mem(ctx->user, nr_pages); if (ret) return ret; } if (ctx->mm_account) atomic64_add(nr_pages, &ctx->mm_account->pinned_vm); return 0; } static void io_mem_free(void *ptr) { struct page *page; if (!ptr) return; page = virt_to_head_page(ptr); if (put_page_testzero(page)) free_compound_page(page); } static void *io_mem_alloc(size_t size) { gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP | __GFP_NORETRY | __GFP_ACCOUNT; return (void *) __get_free_pages(gfp_flags, get_order(size)); } static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries, size_t *sq_offset) { struct io_rings *rings; size_t off, sq_array_size; off = struct_size(rings, cqes, cq_entries); if (off == SIZE_MAX) return SIZE_MAX; #ifdef CONFIG_SMP off = ALIGN(off, SMP_CACHE_BYTES); if (off == 0) return SIZE_MAX; #endif if (sq_offset) *sq_offset = off; sq_array_size = array_size(sizeof(u32), sq_entries); if (sq_array_size == SIZE_MAX) return SIZE_MAX; if (check_add_overflow(off, sq_array_size, &off)) return SIZE_MAX; return off; } static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx) { int i, j; if (!ctx->user_bufs) return -ENXIO; for (i = 0; i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; for (j = 0; j < imu->nr_bvecs; j++) unpin_user_page(imu->bvec[j].bv_page); if (imu->acct_pages) io_unaccount_mem(ctx, imu->acct_pages); kvfree(imu->bvec); imu->nr_bvecs = 0; } kfree(ctx->user_bufs); ctx->user_bufs = NULL; ctx->nr_user_bufs = 0; return 0; } static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, void __user *arg, unsigned index) { struct iovec __user *src; #ifdef CONFIG_COMPAT if (ctx->compat) { struct compat_iovec __user *ciovs; struct compat_iovec ciov; ciovs = (struct compat_iovec __user *) arg; if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) return -EFAULT; dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base); dst->iov_len = ciov.iov_len; return 0; } #endif src = (struct iovec __user *) arg; if (copy_from_user(dst, &src[index], sizeof(*dst))) return -EFAULT; return 0; } /* * Not super efficient, but this is just a registration time. And we do cache * the last compound head, so generally we'll only do a full search if we don't * match that one. * * We check if the given compound head page has already been accounted, to * avoid double accounting it. This allows us to account the full size of the * page, not just the constituent pages of a huge page. */ static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages, int nr_pages, struct page *hpage) { int i, j; /* check current page array */ for (i = 0; i < nr_pages; i++) { if (!PageCompound(pages[i])) continue; if (compound_head(pages[i]) == hpage) return true; } /* check previously registered pages */ for (i = 0; i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; for (j = 0; j < imu->nr_bvecs; j++) { if (!PageCompound(imu->bvec[j].bv_page)) continue; if (compound_head(imu->bvec[j].bv_page) == hpage) return true; } } return false; } static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages, int nr_pages, struct io_mapped_ubuf *imu, struct page **last_hpage) { int i, ret; for (i = 0; i < nr_pages; i++) { if (!PageCompound(pages[i])) { imu->acct_pages++; } else { struct page *hpage; hpage = compound_head(pages[i]); if (hpage == *last_hpage) continue; *last_hpage = hpage; if (headpage_already_acct(ctx, pages, i, hpage)) continue; imu->acct_pages += page_size(hpage) >> PAGE_SHIFT; } } if (!imu->acct_pages) return 0; ret = io_account_mem(ctx, imu->acct_pages); if (ret) imu->acct_pages = 0; return ret; } static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, struct io_mapped_ubuf *imu, struct page **last_hpage) { struct vm_area_struct **vmas = NULL; struct page **pages = NULL; unsigned long off, start, end, ubuf; size_t size; int ret, pret, nr_pages, i; ubuf = (unsigned long) iov->iov_base; end = (ubuf + iov->iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; start = ubuf >> PAGE_SHIFT; nr_pages = end - start; ret = -ENOMEM; pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL); if (!pages) goto done; vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *), GFP_KERNEL); if (!vmas) goto done; imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec), GFP_KERNEL); if (!imu->bvec) goto done; ret = 0; mmap_read_lock(current->mm); pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, pages, vmas); if (pret == nr_pages) { /* don't support file backed memory */ for (i = 0; i < nr_pages; i++) { struct vm_area_struct *vma = vmas[i]; if (vma->vm_file && !is_file_hugepages(vma->vm_file)) { ret = -EOPNOTSUPP; break; } } } else { ret = pret < 0 ? pret : -EFAULT; } mmap_read_unlock(current->mm); if (ret) { /* * if we did partial map, or found file backed vmas, * release any pages we did get */ if (pret > 0) unpin_user_pages(pages, pret); kvfree(imu->bvec); goto done; } ret = io_buffer_account_pin(ctx, pages, pret, imu, last_hpage); if (ret) { unpin_user_pages(pages, pret); kvfree(imu->bvec); goto done; } off = ubuf & ~PAGE_MASK; size = iov->iov_len; for (i = 0; i < nr_pages; i++) { size_t vec_len; vec_len = min_t(size_t, size, PAGE_SIZE - off); imu->bvec[i].bv_page = pages[i]; imu->bvec[i].bv_len = vec_len; imu->bvec[i].bv_offset = off; off = 0; size -= vec_len; } /* store original address for later verification */ imu->ubuf = ubuf; imu->len = iov->iov_len; imu->nr_bvecs = nr_pages; ret = 0; done: kvfree(pages); kvfree(vmas); return ret; } static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args) { if (ctx->user_bufs) return -EBUSY; if (!nr_args || nr_args > UIO_MAXIOV) return -EINVAL; ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf), GFP_KERNEL); if (!ctx->user_bufs) return -ENOMEM; return 0; } static int io_buffer_validate(struct iovec *iov) { /* * Don't impose further limits on the size and buffer * constraints here, we'll -EINVAL later when IO is * submitted if they are wrong. */ if (!iov->iov_base || !iov->iov_len) return -EFAULT; /* arbitrary limit, but we need something */ if (iov->iov_len > SZ_1G) return -EFAULT; return 0; } static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, unsigned int nr_args) { int i, ret; struct iovec iov; struct page *last_hpage = NULL; ret = io_buffers_map_alloc(ctx, nr_args); if (ret) return ret; for (i = 0; i < nr_args; i++) { struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; ret = io_copy_iov(ctx, &iov, arg, i); if (ret) break; ret = io_buffer_validate(&iov); if (ret) break; ret = io_sqe_buffer_register(ctx, &iov, imu, &last_hpage); if (ret) break; ctx->nr_user_bufs++; } if (ret) io_sqe_buffers_unregister(ctx); return ret; } static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg) { __s32 __user *fds = arg; int fd; if (ctx->cq_ev_fd) return -EBUSY; if (copy_from_user(&fd, fds, sizeof(*fds))) return -EFAULT; ctx->cq_ev_fd = eventfd_ctx_fdget(fd); if (IS_ERR(ctx->cq_ev_fd)) { int ret = PTR_ERR(ctx->cq_ev_fd); ctx->cq_ev_fd = NULL; return ret; } return 0; } static int io_eventfd_unregister(struct io_ring_ctx *ctx) { if (ctx->cq_ev_fd) { eventfd_ctx_put(ctx->cq_ev_fd); ctx->cq_ev_fd = NULL; return 0; } return -ENXIO; } static int __io_destroy_buffers(int id, void *p, void *data) { struct io_ring_ctx *ctx = data; struct io_buffer *buf = p; __io_remove_buffers(ctx, buf, id, -1U); return 0; } static void io_destroy_buffers(struct io_ring_ctx *ctx) { idr_for_each(&ctx->io_buffer_idr, __io_destroy_buffers, ctx); idr_destroy(&ctx->io_buffer_idr); } static void io_req_cache_free(struct list_head *list, struct task_struct *tsk) { struct io_kiocb *req, *nxt; list_for_each_entry_safe(req, nxt, list, compl.list) { if (tsk && req->task != tsk) continue; list_del(&req->compl.list); kmem_cache_free(req_cachep, req); } } static void io_req_caches_free(struct io_ring_ctx *ctx, struct task_struct *tsk) { struct io_submit_state *submit_state = &ctx->submit_state; mutex_lock(&ctx->uring_lock); if (submit_state->free_reqs) kmem_cache_free_bulk(req_cachep, submit_state->free_reqs, submit_state->reqs); io_req_cache_free(&submit_state->comp.free_list, NULL); spin_lock_irq(&ctx->completion_lock); io_req_cache_free(&submit_state->comp.locked_free_list, NULL); spin_unlock_irq(&ctx->completion_lock); mutex_unlock(&ctx->uring_lock); } static void io_ring_ctx_free(struct io_ring_ctx *ctx) { /* * Some may use context even when all refs and requests have been put, * and they are free to do so while still holding uring_lock, see * __io_req_task_submit(). Wait for them to finish. */ mutex_lock(&ctx->uring_lock); mutex_unlock(&ctx->uring_lock); io_finish_async(ctx); io_sqe_buffers_unregister(ctx); if (ctx->sqo_task) { put_task_struct(ctx->sqo_task); ctx->sqo_task = NULL; mmdrop(ctx->mm_account); ctx->mm_account = NULL; } #ifdef CONFIG_BLK_CGROUP if (ctx->sqo_blkcg_css) css_put(ctx->sqo_blkcg_css); #endif io_sqe_files_unregister(ctx); io_eventfd_unregister(ctx); io_destroy_buffers(ctx); idr_destroy(&ctx->personality_idr); #if defined(CONFIG_UNIX) if (ctx->ring_sock) { ctx->ring_sock->file = NULL; /* so that iput() is called */ sock_release(ctx->ring_sock); } #endif io_mem_free(ctx->rings); io_mem_free(ctx->sq_sqes); percpu_ref_exit(&ctx->refs); free_uid(ctx->user); put_cred(ctx->creds); io_req_caches_free(ctx, NULL); kfree(ctx->cancel_hash); kfree(ctx); } static __poll_t io_uring_poll(struct file *file, poll_table *wait) { struct io_ring_ctx *ctx = file->private_data; __poll_t mask = 0; poll_wait(file, &ctx->cq_wait, wait); /* * synchronizes with barrier from wq_has_sleeper call in * io_commit_cqring */ smp_rmb(); if (!io_sqring_full(ctx)) mask |= EPOLLOUT | EPOLLWRNORM; /* * Don't flush cqring overflow list here, just do a simple check. * Otherwise there could possible be ABBA deadlock: * CPU0 CPU1 * ---- ---- * lock(&ctx->uring_lock); * lock(&ep->mtx); * lock(&ctx->uring_lock); * lock(&ep->mtx); * * Users may get EPOLLIN meanwhile seeing nothing in cqring, this * pushs them to do the flush. */ if (io_cqring_events(ctx) || test_bit(0, &ctx->cq_check_overflow)) mask |= EPOLLIN | EPOLLRDNORM; return mask; } static int io_uring_fasync(int fd, struct file *file, int on) { struct io_ring_ctx *ctx = file->private_data; return fasync_helper(fd, file, on, &ctx->cq_fasync); } static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id) { struct io_identity *iod; iod = idr_remove(&ctx->personality_idr, id); if (iod) { put_cred(iod->creds); if (refcount_dec_and_test(&iod->count)) kfree(iod); return 0; } return -EINVAL; } static int io_remove_personalities(int id, void *p, void *data) { struct io_ring_ctx *ctx = data; io_unregister_personality(ctx, id); return 0; } static void io_ring_exit_work(struct work_struct *work) { struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work); /* * If we're doing polled IO and end up having requests being * submitted async (out-of-line), then completions can come in while * we're waiting for refs to drop. We need to reap these manually, * as nobody else will be looking for them. */ do { io_uring_try_cancel_requests(ctx, NULL, NULL); } while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20)); io_ring_ctx_free(ctx); } static bool io_cancel_ctx_cb(struct io_wq_work *work, void *data) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); return req->ctx == data; } static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) { mutex_lock(&ctx->uring_lock); percpu_ref_kill(&ctx->refs); if (WARN_ON_ONCE((ctx->flags & IORING_SETUP_SQPOLL) && !ctx->sqo_dead)) ctx->sqo_dead = 1; /* if force is set, the ring is going away. always drop after that */ ctx->cq_overflow_flushed = 1; if (ctx->rings) __io_cqring_overflow_flush(ctx, true, NULL, NULL); idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx); mutex_unlock(&ctx->uring_lock); io_kill_timeouts(ctx, NULL, NULL); io_poll_remove_all(ctx, NULL, NULL); if (ctx->io_wq) io_wq_cancel_cb(ctx->io_wq, io_cancel_ctx_cb, ctx, true); /* if we failed setting up the ctx, we might not have any rings */ io_iopoll_try_reap_events(ctx); INIT_WORK(&ctx->exit_work, io_ring_exit_work); /* * Use system_unbound_wq to avoid spawning tons of event kworkers * if we're exiting a ton of rings at the same time. It just adds * noise and overhead, there's no discernable change in runtime * over using system_wq. */ queue_work(system_unbound_wq, &ctx->exit_work); } static int io_uring_release(struct inode *inode, struct file *file) { struct io_ring_ctx *ctx = file->private_data; file->private_data = NULL; io_ring_ctx_wait_and_kill(ctx); return 0; } struct io_task_cancel { struct task_struct *task; struct files_struct *files; }; static bool io_cancel_task_cb(struct io_wq_work *work, void *data) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct io_task_cancel *cancel = data; bool ret; if (cancel->files && (req->flags & REQ_F_LINK_TIMEOUT)) { unsigned long flags; struct io_ring_ctx *ctx = req->ctx; /* protect against races with linked timeouts */ spin_lock_irqsave(&ctx->completion_lock, flags); ret = io_match_task(req, cancel->task, cancel->files); spin_unlock_irqrestore(&ctx->completion_lock, flags); } else { ret = io_match_task(req, cancel->task, cancel->files); } return ret; } static void io_cancel_defer_files(struct io_ring_ctx *ctx, struct task_struct *task, struct files_struct *files) { struct io_defer_entry *de = NULL; LIST_HEAD(list); spin_lock_irq(&ctx->completion_lock); list_for_each_entry_reverse(de, &ctx->defer_list, list) { if (io_match_task(de->req, task, files)) { list_cut_position(&list, &ctx->defer_list, &de->list); break; } } spin_unlock_irq(&ctx->completion_lock); while (!list_empty(&list)) { de = list_first_entry(&list, struct io_defer_entry, list); list_del_init(&de->list); req_set_fail_links(de->req); io_put_req(de->req); io_req_complete(de->req, -ECANCELED); kfree(de); } } static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx, struct task_struct *task, struct files_struct *files) { struct io_task_cancel cancel = { .task = task, .files = files, }; while (1) { enum io_wq_cancel cret; bool ret = false; if (ctx->io_wq) { cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_task_cb, &cancel, true); ret |= (cret != IO_WQ_CANCEL_NOTFOUND); } /* SQPOLL thread does its own polling */ if (!(ctx->flags & IORING_SETUP_SQPOLL) && !files) { while (!list_empty_careful(&ctx->iopoll_list)) { io_iopoll_try_reap_events(ctx); ret = true; } } ret |= io_poll_remove_all(ctx, task, files); ret |= io_kill_timeouts(ctx, task, files); ret |= io_run_task_work(); io_cqring_overflow_flush(ctx, true, task, files); if (!ret) break; cond_resched(); } } static int io_uring_count_inflight(struct io_ring_ctx *ctx, struct task_struct *task, struct files_struct *files) { struct io_kiocb *req; int cnt = 0; spin_lock_irq(&ctx->inflight_lock); list_for_each_entry(req, &ctx->inflight_list, inflight_entry) cnt += io_match_task(req, task, files); spin_unlock_irq(&ctx->inflight_lock); return cnt; } static void io_uring_cancel_files(struct io_ring_ctx *ctx, struct task_struct *task, struct files_struct *files) { while (!list_empty_careful(&ctx->inflight_list)) { DEFINE_WAIT(wait); int inflight; inflight = io_uring_count_inflight(ctx, task, files); if (!inflight) break; io_uring_try_cancel_requests(ctx, task, files); if (ctx->sq_data) io_sq_thread_unpark(ctx->sq_data); prepare_to_wait(&task->io_uring->wait, &wait, TASK_UNINTERRUPTIBLE); if (inflight == io_uring_count_inflight(ctx, task, files)) schedule(); finish_wait(&task->io_uring->wait, &wait); if (ctx->sq_data) io_sq_thread_park(ctx->sq_data); } } static void io_disable_sqo_submit(struct io_ring_ctx *ctx) { mutex_lock(&ctx->uring_lock); ctx->sqo_dead = 1; mutex_unlock(&ctx->uring_lock); /* make sure callers enter the ring to get error */ if (ctx->rings) io_ring_set_wakeup_flag(ctx); } /* * We need to iteratively cancel requests, in case a request has dependent * hard links. These persist even for failure of cancelations, hence keep * looping until none are found. */ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx, struct files_struct *files) { struct task_struct *task = current; if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) { io_disable_sqo_submit(ctx); task = ctx->sq_data->thread; atomic_inc(&task->io_uring->in_idle); io_sq_thread_park(ctx->sq_data); } io_cancel_defer_files(ctx, task, files); io_uring_cancel_files(ctx, task, files); if (!files) io_uring_try_cancel_requests(ctx, task, NULL); if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) { atomic_dec(&task->io_uring->in_idle); /* * If the files that are going away are the ones in the thread * identity, clear them out. */ if (task->io_uring->identity->files == files) task->io_uring->identity->files = NULL; io_sq_thread_unpark(ctx->sq_data); } } /* * Note that this task has used io_uring. We use it for cancelation purposes. */ static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file) { struct io_uring_task *tctx = current->io_uring; int ret; if (unlikely(!tctx)) { ret = io_uring_alloc_task_context(current); if (unlikely(ret)) return ret; tctx = current->io_uring; } if (tctx->last != file) { void *old = xa_load(&tctx->xa, (unsigned long)file); if (!old) { get_file(file); ret = xa_err(xa_store(&tctx->xa, (unsigned long)file, file, GFP_KERNEL)); if (ret) { fput(file); return ret; } /* one and only SQPOLL file note, held by sqo_task */ WARN_ON_ONCE((ctx->flags & IORING_SETUP_SQPOLL) && current != ctx->sqo_task); } tctx->last = file; } /* * This is race safe in that the task itself is doing this, hence it * cannot be going through the exit/cancel paths at the same time. * This cannot be modified while exit/cancel is running. */ if (!tctx->sqpoll && (ctx->flags & IORING_SETUP_SQPOLL)) tctx->sqpoll = true; return 0; } /* * Remove this io_uring_file -> task mapping. */ static void io_uring_del_task_file(struct file *file) { struct io_uring_task *tctx = current->io_uring; if (tctx->last == file) tctx->last = NULL; file = xa_erase(&tctx->xa, (unsigned long)file); if (file) fput(file); } static void io_uring_remove_task_files(struct io_uring_task *tctx) { struct file *file; unsigned long index; xa_for_each(&tctx->xa, index, file) io_uring_del_task_file(file); } void __io_uring_files_cancel(struct files_struct *files) { struct io_uring_task *tctx = current->io_uring; struct file *file; unsigned long index; /* make sure overflow events are dropped */ atomic_inc(&tctx->in_idle); xa_for_each(&tctx->xa, index, file) io_uring_cancel_task_requests(file->private_data, files); atomic_dec(&tctx->in_idle); if (files) io_uring_remove_task_files(tctx); } static s64 tctx_inflight(struct io_uring_task *tctx) { return percpu_counter_sum(&tctx->inflight); } static void io_uring_cancel_sqpoll(struct io_ring_ctx *ctx) { struct io_uring_task *tctx; s64 inflight; DEFINE_WAIT(wait); if (!ctx->sq_data) return; tctx = ctx->sq_data->thread->io_uring; io_disable_sqo_submit(ctx); atomic_inc(&tctx->in_idle); do { /* read completions before cancelations */ inflight = tctx_inflight(tctx); if (!inflight) break; io_uring_cancel_task_requests(ctx, NULL); prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE); /* * If we've seen completions, retry without waiting. This * avoids a race where a completion comes in before we did * prepare_to_wait(). */ if (inflight == tctx_inflight(tctx)) schedule(); finish_wait(&tctx->wait, &wait); } while (1); atomic_dec(&tctx->in_idle); } /* * Find any io_uring fd that this task has registered or done IO on, and cancel * requests. */ void __io_uring_task_cancel(void) { struct io_uring_task *tctx = current->io_uring; DEFINE_WAIT(wait); s64 inflight; /* make sure overflow events are dropped */ atomic_inc(&tctx->in_idle); /* trigger io_disable_sqo_submit() */ if (tctx->sqpoll) { struct file *file; unsigned long index; xa_for_each(&tctx->xa, index, file) io_uring_cancel_sqpoll(file->private_data); } do { /* read completions before cancelations */ inflight = tctx_inflight(tctx); if (!inflight) break; __io_uring_files_cancel(NULL); prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE); /* * If we've seen completions, retry without waiting. This * avoids a race where a completion comes in before we did * prepare_to_wait(). */ if (inflight == tctx_inflight(tctx)) schedule(); finish_wait(&tctx->wait, &wait); } while (1); atomic_dec(&tctx->in_idle); io_uring_remove_task_files(tctx); } static int io_uring_flush(struct file *file, void *data) { struct io_uring_task *tctx = current->io_uring; struct io_ring_ctx *ctx = file->private_data; if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) { io_uring_cancel_task_requests(ctx, NULL); io_req_caches_free(ctx, current); } if (!tctx) return 0; /* we should have cancelled and erased it before PF_EXITING */ WARN_ON_ONCE((current->flags & PF_EXITING) && xa_load(&tctx->xa, (unsigned long)file)); /* * fput() is pending, will be 2 if the only other ref is our potential * task file note. If the task is exiting, drop regardless of count. */ if (atomic_long_read(&file->f_count) != 2) return 0; if (ctx->flags & IORING_SETUP_SQPOLL) { /* there is only one file note, which is owned by sqo_task */ WARN_ON_ONCE(ctx->sqo_task != current && xa_load(&tctx->xa, (unsigned long)file)); /* sqo_dead check is for when this happens after cancellation */ WARN_ON_ONCE(ctx->sqo_task == current && !ctx->sqo_dead && !xa_load(&tctx->xa, (unsigned long)file)); io_disable_sqo_submit(ctx); } if (!(ctx->flags & IORING_SETUP_SQPOLL) || ctx->sqo_task == current) io_uring_del_task_file(file); return 0; } static void *io_uring_validate_mmap_request(struct file *file, loff_t pgoff, size_t sz) { struct io_ring_ctx *ctx = file->private_data; loff_t offset = pgoff << PAGE_SHIFT; struct page *page; void *ptr; switch (offset) { case IORING_OFF_SQ_RING: case IORING_OFF_CQ_RING: ptr = ctx->rings; break; case IORING_OFF_SQES: ptr = ctx->sq_sqes; break; default: return ERR_PTR(-EINVAL); } page = virt_to_head_page(ptr); if (sz > page_size(page)) return ERR_PTR(-EINVAL); return ptr; } #ifdef CONFIG_MMU static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) { size_t sz = vma->vm_end - vma->vm_start; unsigned long pfn; void *ptr; ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz); if (IS_ERR(ptr)) return PTR_ERR(ptr); pfn = virt_to_phys(ptr) >> PAGE_SHIFT; return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); } #else /* !CONFIG_MMU */ static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) { return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL; } static unsigned int io_uring_nommu_mmap_capabilities(struct file *file) { return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE; } static unsigned long io_uring_nommu_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { void *ptr; ptr = io_uring_validate_mmap_request(file, pgoff, len); if (IS_ERR(ptr)) return PTR_ERR(ptr); return (unsigned long) ptr; } #endif /* !CONFIG_MMU */ static int io_sqpoll_wait_sq(struct io_ring_ctx *ctx) { int ret = 0; DEFINE_WAIT(wait); do { if (!io_sqring_full(ctx)) break; prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE); if (unlikely(ctx->sqo_dead)) { ret = -EOWNERDEAD; goto out; } if (!io_sqring_full(ctx)) break; schedule(); } while (!signal_pending(current)); finish_wait(&ctx->sqo_sq_wait, &wait); out: return ret; } static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz, struct __kernel_timespec __user **ts, const sigset_t __user **sig) { struct io_uring_getevents_arg arg; /* * If EXT_ARG isn't set, then we have no timespec and the argp pointer * is just a pointer to the sigset_t. */ if (!(flags & IORING_ENTER_EXT_ARG)) { *sig = (const sigset_t __user *) argp; *ts = NULL; return 0; } /* * EXT_ARG is set - ensure we agree on the size of it and copy in our * timespec and sigset_t pointers if good. */ if (*argsz != sizeof(arg)) return -EINVAL; if (copy_from_user(&arg, argp, sizeof(arg))) return -EFAULT; *sig = u64_to_user_ptr(arg.sigmask); *argsz = arg.sigmask_sz; *ts = u64_to_user_ptr(arg.ts); return 0; } SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, u32, min_complete, u32, flags, const void __user *, argp, size_t, argsz) { struct io_ring_ctx *ctx; long ret = -EBADF; int submitted = 0; struct fd f; io_run_task_work(); if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP | IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG)) return -EINVAL; f = fdget(fd); if (!f.file) return -EBADF; ret = -EOPNOTSUPP; if (f.file->f_op != &io_uring_fops) goto out_fput; ret = -ENXIO; ctx = f.file->private_data; if (!percpu_ref_tryget(&ctx->refs)) goto out_fput; ret = -EBADFD; if (ctx->flags & IORING_SETUP_R_DISABLED) goto out; /* * For SQ polling, the thread will do all submissions and completions. * Just return the requested submit count, and wake the thread if * we were asked to. */ ret = 0; if (ctx->flags & IORING_SETUP_SQPOLL) { io_cqring_overflow_flush(ctx, false, NULL, NULL); ret = -EOWNERDEAD; if (unlikely(ctx->sqo_dead)) goto out; if (flags & IORING_ENTER_SQ_WAKEUP) wake_up(&ctx->sq_data->wait); if (flags & IORING_ENTER_SQ_WAIT) { ret = io_sqpoll_wait_sq(ctx); if (ret) goto out; } submitted = to_submit; } else if (to_submit) { ret = io_uring_add_task_file(ctx, f.file); if (unlikely(ret)) goto out; mutex_lock(&ctx->uring_lock); submitted = io_submit_sqes(ctx, to_submit); mutex_unlock(&ctx->uring_lock); if (submitted != to_submit) goto out; } if (flags & IORING_ENTER_GETEVENTS) { const sigset_t __user *sig; struct __kernel_timespec __user *ts; ret = io_get_ext_arg(flags, argp, &argsz, &ts, &sig); if (unlikely(ret)) goto out; min_complete = min(min_complete, ctx->cq_entries); /* * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user * space applications don't need to do io completion events * polling again, they can rely on io_sq_thread to do polling * work, which can reduce cpu usage and uring_lock contention. */ if (ctx->flags & IORING_SETUP_IOPOLL && !(ctx->flags & IORING_SETUP_SQPOLL)) { ret = io_iopoll_check(ctx, min_complete); } else { ret = io_cqring_wait(ctx, min_complete, sig, argsz, ts); } } out: percpu_ref_put(&ctx->refs); out_fput: fdput(f); return submitted ? submitted : ret; } #ifdef CONFIG_PROC_FS static int io_uring_show_cred(int id, void *p, void *data) { struct io_identity *iod = p; const struct cred *cred = iod->creds; struct seq_file *m = data; struct user_namespace *uns = seq_user_ns(m); struct group_info *gi; kernel_cap_t cap; unsigned __capi; int g; seq_printf(m, "%5d\n", id); seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid)); seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid)); seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid)); seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid)); seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid)); seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid)); seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid)); seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid)); seq_puts(m, "\n\tGroups:\t"); gi = cred->group_info; for (g = 0; g < gi->ngroups; g++) { seq_put_decimal_ull(m, g ? " " : "", from_kgid_munged(uns, gi->gid[g])); } seq_puts(m, "\n\tCapEff:\t"); cap = cred->cap_effective; CAP_FOR_EACH_U32(__capi) seq_put_hex_ll(m, NULL, cap.cap[CAP_LAST_U32 - __capi], 8); seq_putc(m, '\n'); return 0; } static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) { struct io_sq_data *sq = NULL; bool has_lock; int i; /* * Avoid ABBA deadlock between the seq lock and the io_uring mutex, * since fdinfo case grabs it in the opposite direction of normal use * cases. If we fail to get the lock, we just don't iterate any * structures that could be going away outside the io_uring mutex. */ has_lock = mutex_trylock(&ctx->uring_lock); if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL)) sq = ctx->sq_data; seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1); seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1); seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files); for (i = 0; has_lock && i < ctx->nr_user_files; i++) { struct file *f = *io_fixed_file_slot(ctx->file_data, i); if (f) seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname); else seq_printf(m, "%5u: \n", i); } seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs); for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *buf = &ctx->user_bufs[i]; seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, (unsigned int) buf->len); } if (has_lock && !idr_is_empty(&ctx->personality_idr)) { seq_printf(m, "Personalities:\n"); idr_for_each(&ctx->personality_idr, io_uring_show_cred, m); } seq_printf(m, "PollList:\n"); spin_lock_irq(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { struct hlist_head *list = &ctx->cancel_hash[i]; struct io_kiocb *req; hlist_for_each_entry(req, list, hash_node) seq_printf(m, " op=%d, task_works=%d\n", req->opcode, req->task->task_works != NULL); } spin_unlock_irq(&ctx->completion_lock); if (has_lock) mutex_unlock(&ctx->uring_lock); } static void io_uring_show_fdinfo(struct seq_file *m, struct file *f) { struct io_ring_ctx *ctx = f->private_data; if (percpu_ref_tryget(&ctx->refs)) { __io_uring_show_fdinfo(ctx, m); percpu_ref_put(&ctx->refs); } } #endif static const struct file_operations io_uring_fops = { .release = io_uring_release, .flush = io_uring_flush, .mmap = io_uring_mmap, #ifndef CONFIG_MMU .get_unmapped_area = io_uring_nommu_get_unmapped_area, .mmap_capabilities = io_uring_nommu_mmap_capabilities, #endif .poll = io_uring_poll, .fasync = io_uring_fasync, #ifdef CONFIG_PROC_FS .show_fdinfo = io_uring_show_fdinfo, #endif }; static int io_allocate_scq_urings(struct io_ring_ctx *ctx, struct io_uring_params *p) { struct io_rings *rings; size_t size, sq_array_offset; /* make sure these are sane, as we already accounted them */ ctx->sq_entries = p->sq_entries; ctx->cq_entries = p->cq_entries; size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset); if (size == SIZE_MAX) return -EOVERFLOW; rings = io_mem_alloc(size); if (!rings) return -ENOMEM; ctx->rings = rings; ctx->sq_array = (u32 *)((char *)rings + sq_array_offset); rings->sq_ring_mask = p->sq_entries - 1; rings->cq_ring_mask = p->cq_entries - 1; rings->sq_ring_entries = p->sq_entries; rings->cq_ring_entries = p->cq_entries; ctx->sq_mask = rings->sq_ring_mask; ctx->cq_mask = rings->cq_ring_mask; size = array_size(sizeof(struct io_uring_sqe), p->sq_entries); if (size == SIZE_MAX) { io_mem_free(ctx->rings); ctx->rings = NULL; return -EOVERFLOW; } ctx->sq_sqes = io_mem_alloc(size); if (!ctx->sq_sqes) { io_mem_free(ctx->rings); ctx->rings = NULL; return -ENOMEM; } return 0; } static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file) { int ret, fd; fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC); if (fd < 0) return fd; ret = io_uring_add_task_file(ctx, file); if (ret) { put_unused_fd(fd); return ret; } fd_install(fd, file); return fd; } /* * Allocate an anonymous fd, this is what constitutes the application * visible backing of an io_uring instance. The application mmaps this * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled, * we have to tie this fd to a socket for file garbage collection purposes. */ static struct file *io_uring_get_file(struct io_ring_ctx *ctx) { struct file *file; #if defined(CONFIG_UNIX) int ret; ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP, &ctx->ring_sock); if (ret) return ERR_PTR(ret); #endif file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx, O_RDWR | O_CLOEXEC); #if defined(CONFIG_UNIX) if (IS_ERR(file)) { sock_release(ctx->ring_sock); ctx->ring_sock = NULL; } else { ctx->ring_sock->file = file; } #endif return file; } static int io_uring_create(unsigned entries, struct io_uring_params *p, struct io_uring_params __user *params) { struct user_struct *user = NULL; struct io_ring_ctx *ctx; struct file *file; int ret; if (!entries) return -EINVAL; if (entries > IORING_MAX_ENTRIES) { if (!(p->flags & IORING_SETUP_CLAMP)) return -EINVAL; entries = IORING_MAX_ENTRIES; } /* * Use twice as many entries for the CQ ring. It's possible for the * application to drive a higher depth than the size of the SQ ring, * since the sqes are only used at submission time. This allows for * some flexibility in overcommitting a bit. If the application has * set IORING_SETUP_CQSIZE, it will have passed in the desired number * of CQ ring entries manually. */ p->sq_entries = roundup_pow_of_two(entries); if (p->flags & IORING_SETUP_CQSIZE) { /* * If IORING_SETUP_CQSIZE is set, we do the same roundup * to a power-of-two, if it isn't already. We do NOT impose * any cq vs sq ring sizing. */ if (!p->cq_entries) return -EINVAL; if (p->cq_entries > IORING_MAX_CQ_ENTRIES) { if (!(p->flags & IORING_SETUP_CLAMP)) return -EINVAL; p->cq_entries = IORING_MAX_CQ_ENTRIES; } p->cq_entries = roundup_pow_of_two(p->cq_entries); if (p->cq_entries < p->sq_entries) return -EINVAL; } else { p->cq_entries = 2 * p->sq_entries; } user = get_uid(current_user()); ctx = io_ring_ctx_alloc(p); if (!ctx) { free_uid(user); return -ENOMEM; } ctx->compat = in_compat_syscall(); ctx->limit_mem = !capable(CAP_IPC_LOCK); ctx->user = user; ctx->creds = get_current_cred(); #ifdef CONFIG_AUDIT ctx->loginuid = current->loginuid; ctx->sessionid = current->sessionid; #endif ctx->sqo_task = get_task_struct(current); /* * This is just grabbed for accounting purposes. When a process exits, * the mm is exited and dropped before the files, hence we need to hang * on to this mm purely for the purposes of being able to unaccount * memory (locked/pinned vm). It's not used for anything else. */ mmgrab(current->mm); ctx->mm_account = current->mm; #ifdef CONFIG_BLK_CGROUP /* * The sq thread will belong to the original cgroup it was inited in. * If the cgroup goes offline (e.g. disabling the io controller), then * issued bios will be associated with the closest cgroup later in the * block layer. */ rcu_read_lock(); ctx->sqo_blkcg_css = blkcg_css(); ret = css_tryget_online(ctx->sqo_blkcg_css); rcu_read_unlock(); if (!ret) { /* don't init against a dying cgroup, have the user try again */ ctx->sqo_blkcg_css = NULL; ret = -ENODEV; goto err; } #endif ret = io_allocate_scq_urings(ctx, p); if (ret) goto err; ret = io_sq_offload_create(ctx, p); if (ret) goto err; if (!(p->flags & IORING_SETUP_R_DISABLED)) io_sq_offload_start(ctx); memset(&p->sq_off, 0, sizeof(p->sq_off)); p->sq_off.head = offsetof(struct io_rings, sq.head); p->sq_off.tail = offsetof(struct io_rings, sq.tail); p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask); p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries); p->sq_off.flags = offsetof(struct io_rings, sq_flags); p->sq_off.dropped = offsetof(struct io_rings, sq_dropped); p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings; memset(&p->cq_off, 0, sizeof(p->cq_off)); p->cq_off.head = offsetof(struct io_rings, cq.head); p->cq_off.tail = offsetof(struct io_rings, cq.tail); p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask); p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries); p->cq_off.overflow = offsetof(struct io_rings, cq_overflow); p->cq_off.cqes = offsetof(struct io_rings, cqes); p->cq_off.flags = offsetof(struct io_rings, cq_flags); p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP | IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS | IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL | IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED | IORING_FEAT_EXT_ARG; if (copy_to_user(params, p, sizeof(*p))) { ret = -EFAULT; goto err; } file = io_uring_get_file(ctx); if (IS_ERR(file)) { ret = PTR_ERR(file); goto err; } /* * Install ring fd as the very last thing, so we don't risk someone * having closed it before we finish setup */ ret = io_uring_install_fd(ctx, file); if (ret < 0) { io_disable_sqo_submit(ctx); /* fput will clean it up */ fput(file); return ret; } trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags); return ret; err: io_disable_sqo_submit(ctx); io_ring_ctx_wait_and_kill(ctx); return ret; } /* * Sets up an aio uring context, and returns the fd. Applications asks for a * ring size, we return the actual sq/cq ring sizes (among other things) in the * params structure passed in. */ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) { struct io_uring_params p; int i; if (copy_from_user(&p, params, sizeof(p))) return -EFAULT; for (i = 0; i < ARRAY_SIZE(p.resv); i++) { if (p.resv[i]) return -EINVAL; } if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE | IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ | IORING_SETUP_R_DISABLED)) return -EINVAL; return io_uring_create(entries, &p, params); } SYSCALL_DEFINE2(io_uring_setup, u32, entries, struct io_uring_params __user *, params) { return io_uring_setup(entries, params); } static int io_probe(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct io_uring_probe *p; size_t size; int i, ret; size = struct_size(p, ops, nr_args); if (size == SIZE_MAX) return -EOVERFLOW; p = kzalloc(size, GFP_KERNEL); if (!p) return -ENOMEM; ret = -EFAULT; if (copy_from_user(p, arg, size)) goto out; ret = -EINVAL; if (memchr_inv(p, 0, size)) goto out; p->last_op = IORING_OP_LAST - 1; if (nr_args > IORING_OP_LAST) nr_args = IORING_OP_LAST; for (i = 0; i < nr_args; i++) { p->ops[i].op = i; if (!io_op_defs[i].not_supported) p->ops[i].flags = IO_URING_OP_SUPPORTED; } p->ops_len = i; ret = 0; if (copy_to_user(arg, p, size)) ret = -EFAULT; out: kfree(p); return ret; } static int io_register_personality(struct io_ring_ctx *ctx) { struct io_identity *id; int ret; id = kmalloc(sizeof(*id), GFP_KERNEL); if (unlikely(!id)) return -ENOMEM; io_init_identity(id); id->creds = get_current_cred(); ret = idr_alloc_cyclic(&ctx->personality_idr, id, 1, USHRT_MAX, GFP_KERNEL); if (ret < 0) { put_cred(id->creds); kfree(id); } return ret; } static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg, unsigned int nr_args) { struct io_uring_restriction *res; size_t size; int i, ret; /* Restrictions allowed only if rings started disabled */ if (!(ctx->flags & IORING_SETUP_R_DISABLED)) return -EBADFD; /* We allow only a single restrictions registration */ if (ctx->restrictions.registered) return -EBUSY; if (!arg || nr_args > IORING_MAX_RESTRICTIONS) return -EINVAL; size = array_size(nr_args, sizeof(*res)); if (size == SIZE_MAX) return -EOVERFLOW; res = memdup_user(arg, size); if (IS_ERR(res)) return PTR_ERR(res); ret = 0; for (i = 0; i < nr_args; i++) { switch (res[i].opcode) { case IORING_RESTRICTION_REGISTER_OP: if (res[i].register_op >= IORING_REGISTER_LAST) { ret = -EINVAL; goto out; } __set_bit(res[i].register_op, ctx->restrictions.register_op); break; case IORING_RESTRICTION_SQE_OP: if (res[i].sqe_op >= IORING_OP_LAST) { ret = -EINVAL; goto out; } __set_bit(res[i].sqe_op, ctx->restrictions.sqe_op); break; case IORING_RESTRICTION_SQE_FLAGS_ALLOWED: ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags; break; case IORING_RESTRICTION_SQE_FLAGS_REQUIRED: ctx->restrictions.sqe_flags_required = res[i].sqe_flags; break; default: ret = -EINVAL; goto out; } } out: /* Reset all restrictions if an error happened */ if (ret != 0) memset(&ctx->restrictions, 0, sizeof(ctx->restrictions)); else ctx->restrictions.registered = true; kfree(res); return ret; } static int io_register_enable_rings(struct io_ring_ctx *ctx) { if (!(ctx->flags & IORING_SETUP_R_DISABLED)) return -EBADFD; if (ctx->restrictions.registered) ctx->restricted = 1; ctx->flags &= ~IORING_SETUP_R_DISABLED; io_sq_offload_start(ctx); return 0; } static bool io_register_op_must_quiesce(int op) { switch (op) { case IORING_UNREGISTER_FILES: case IORING_REGISTER_FILES_UPDATE: case IORING_REGISTER_PROBE: case IORING_REGISTER_PERSONALITY: case IORING_UNREGISTER_PERSONALITY: return false; default: return true; } } static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, void __user *arg, unsigned nr_args) __releases(ctx->uring_lock) __acquires(ctx->uring_lock) { int ret; /* * We're inside the ring mutex, if the ref is already dying, then * someone else killed the ctx or is already going through * io_uring_register(). */ if (percpu_ref_is_dying(&ctx->refs)) return -ENXIO; if (io_register_op_must_quiesce(opcode)) { percpu_ref_kill(&ctx->refs); /* * Drop uring mutex before waiting for references to exit. If * another thread is currently inside io_uring_enter() it might * need to grab the uring_lock to make progress. If we hold it * here across the drain wait, then we can deadlock. It's safe * to drop the mutex here, since no new references will come in * after we've killed the percpu ref. */ mutex_unlock(&ctx->uring_lock); do { ret = wait_for_completion_interruptible(&ctx->ref_comp); if (!ret) break; ret = io_run_task_work_sig(); if (ret < 0) break; } while (1); mutex_lock(&ctx->uring_lock); if (ret) { percpu_ref_resurrect(&ctx->refs); goto out_quiesce; } } if (ctx->restricted) { if (opcode >= IORING_REGISTER_LAST) { ret = -EINVAL; goto out; } if (!test_bit(opcode, ctx->restrictions.register_op)) { ret = -EACCES; goto out; } } switch (opcode) { case IORING_REGISTER_BUFFERS: ret = io_sqe_buffers_register(ctx, arg, nr_args); break; case IORING_UNREGISTER_BUFFERS: ret = -EINVAL; if (arg || nr_args) break; ret = io_sqe_buffers_unregister(ctx); break; case IORING_REGISTER_FILES: ret = io_sqe_files_register(ctx, arg, nr_args); break; case IORING_UNREGISTER_FILES: ret = -EINVAL; if (arg || nr_args) break; ret = io_sqe_files_unregister(ctx); break; case IORING_REGISTER_FILES_UPDATE: ret = io_sqe_files_update(ctx, arg, nr_args); break; case IORING_REGISTER_EVENTFD: case IORING_REGISTER_EVENTFD_ASYNC: ret = -EINVAL; if (nr_args != 1) break; ret = io_eventfd_register(ctx, arg); if (ret) break; if (opcode == IORING_REGISTER_EVENTFD_ASYNC) ctx->eventfd_async = 1; else ctx->eventfd_async = 0; break; case IORING_UNREGISTER_EVENTFD: ret = -EINVAL; if (arg || nr_args) break; ret = io_eventfd_unregister(ctx); break; case IORING_REGISTER_PROBE: ret = -EINVAL; if (!arg || nr_args > 256) break; ret = io_probe(ctx, arg, nr_args); break; case IORING_REGISTER_PERSONALITY: ret = -EINVAL; if (arg || nr_args) break; ret = io_register_personality(ctx); break; case IORING_UNREGISTER_PERSONALITY: ret = -EINVAL; if (arg) break; ret = io_unregister_personality(ctx, nr_args); break; case IORING_REGISTER_ENABLE_RINGS: ret = -EINVAL; if (arg || nr_args) break; ret = io_register_enable_rings(ctx); break; case IORING_REGISTER_RESTRICTIONS: ret = io_register_restrictions(ctx, arg, nr_args); break; default: ret = -EINVAL; break; } out: if (io_register_op_must_quiesce(opcode)) { /* bring the ctx back to life */ percpu_ref_reinit(&ctx->refs); out_quiesce: reinit_completion(&ctx->ref_comp); } return ret; } SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, void __user *, arg, unsigned int, nr_args) { struct io_ring_ctx *ctx; long ret = -EBADF; struct fd f; f = fdget(fd); if (!f.file) return -EBADF; ret = -EOPNOTSUPP; if (f.file->f_op != &io_uring_fops) goto out_fput; ctx = f.file->private_data; mutex_lock(&ctx->uring_lock); ret = __io_uring_register(ctx, opcode, arg, nr_args); mutex_unlock(&ctx->uring_lock); trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ctx->cq_ev_fd != NULL, ret); out_fput: fdput(f); return ret; } static int __init io_uring_init(void) { #define __BUILD_BUG_VERIFY_ELEMENT(stype, eoffset, etype, ename) do { \ BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \ BUILD_BUG_ON(sizeof(etype) != sizeof_field(stype, ename)); \ } while (0) #define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \ __BUILD_BUG_VERIFY_ELEMENT(struct io_uring_sqe, eoffset, etype, ename) BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64); BUILD_BUG_SQE_ELEM(0, __u8, opcode); BUILD_BUG_SQE_ELEM(1, __u8, flags); BUILD_BUG_SQE_ELEM(2, __u16, ioprio); BUILD_BUG_SQE_ELEM(4, __s32, fd); BUILD_BUG_SQE_ELEM(8, __u64, off); BUILD_BUG_SQE_ELEM(8, __u64, addr2); BUILD_BUG_SQE_ELEM(16, __u64, addr); BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in); BUILD_BUG_SQE_ELEM(24, __u32, len); BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags); BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags); BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags); BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags); BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events); BUILD_BUG_SQE_ELEM(28, __u32, poll32_events); BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags); BUILD_BUG_SQE_ELEM(28, __u32, msg_flags); BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags); BUILD_BUG_SQE_ELEM(28, __u32, accept_flags); BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags); BUILD_BUG_SQE_ELEM(28, __u32, open_flags); BUILD_BUG_SQE_ELEM(28, __u32, statx_flags); BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice); BUILD_BUG_SQE_ELEM(28, __u32, splice_flags); BUILD_BUG_SQE_ELEM(32, __u64, user_data); BUILD_BUG_SQE_ELEM(40, __u16, buf_index); BUILD_BUG_SQE_ELEM(42, __u16, personality); BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in); BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST); BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int)); req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT); return 0; }; __initcall(io_uring_init);