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authorJens Axboe <axboe@kernel.dk>2022-05-25 20:31:09 -0600
committerJens Axboe <axboe@kernel.dk>2022-07-24 18:39:12 -0600
commit329061d3e2f9a0082a097e9558bd5497098586c6 (patch)
tree3a0d34b89b6ef8df26c0ca04a7c60732ada208af /io_uring/poll.c
parentcfd22e6b3319adc7c2a8a092e19ac16575dabc86 (diff)
downloadlwn-329061d3e2f9a0082a097e9558bd5497098586c6.tar.gz
lwn-329061d3e2f9a0082a097e9558bd5497098586c6.zip
io_uring: move poll handling into its own file
Add a io_poll_issue() rather than export the general task_work locking and io_issue_sqe(), and put the io_op_defs definition and structure into a separate header file so that poll can use it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/poll.c')
-rw-r--r--io_uring/poll.c760
1 files changed, 760 insertions, 0 deletions
diff --git a/io_uring/poll.c b/io_uring/poll.c
new file mode 100644
index 000000000000..c3e4fcb0a7ba
--- /dev/null
+++ b/io_uring/poll.c
@@ -0,0 +1,760 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/hashtable.h>
+#include <linux/io_uring.h>
+
+#include <trace/events/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring_types.h"
+#include "io_uring.h"
+#include "refs.h"
+#include "opdef.h"
+#include "poll.h"
+
+struct io_poll_update {
+ struct file *file;
+ u64 old_user_data;
+ u64 new_user_data;
+ __poll_t events;
+ bool update_events;
+ bool update_user_data;
+};
+
+struct io_poll_table {
+ struct poll_table_struct pt;
+ struct io_kiocb *req;
+ int nr_entries;
+ int error;
+};
+
+#define IO_POLL_CANCEL_FLAG BIT(31)
+#define IO_POLL_REF_MASK GENMASK(30, 0)
+
+/*
+ * If refs part of ->poll_refs (see IO_POLL_REF_MASK) is 0, it's free. We can
+ * bump it and acquire ownership. It's disallowed to modify requests while not
+ * owning it, that prevents from races for enqueueing task_work's and b/w
+ * arming poll and wakeups.
+ */
+static inline bool io_poll_get_ownership(struct io_kiocb *req)
+{
+ return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
+}
+
+static void io_poll_mark_cancelled(struct io_kiocb *req)
+{
+ atomic_or(IO_POLL_CANCEL_FLAG, &req->poll_refs);
+}
+
+static struct io_poll *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 *io_poll_get_single(struct io_kiocb *req)
+{
+ if (req->opcode == IORING_OP_POLL_ADD)
+ return io_kiocb_to_cmd(req);
+ return &req->apoll->poll;
+}
+
+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->cqe.user_data, ctx->cancel_hash_bits)];
+ hlist_add_head(&req->hash_node, list);
+}
+
+static void io_init_poll_iocb(struct io_poll *poll, __poll_t events,
+ wait_queue_func_t wake_func)
+{
+ poll->head = NULL;
+#define IO_POLL_UNMASK (EPOLLERR|EPOLLHUP|EPOLLNVAL|EPOLLRDHUP)
+ /* mask in events that we always want/need */
+ poll->events = events | IO_POLL_UNMASK;
+ INIT_LIST_HEAD(&poll->wait.entry);
+ init_waitqueue_func_entry(&poll->wait, wake_func);
+}
+
+static inline void io_poll_remove_entry(struct io_poll *poll)
+{
+ struct wait_queue_head *head = smp_load_acquire(&poll->head);
+
+ if (head) {
+ spin_lock_irq(&head->lock);
+ list_del_init(&poll->wait.entry);
+ poll->head = NULL;
+ spin_unlock_irq(&head->lock);
+ }
+}
+
+static void io_poll_remove_entries(struct io_kiocb *req)
+{
+ /*
+ * Nothing to do if neither of those flags are set. Avoid dipping
+ * into the poll/apoll/double cachelines if we can.
+ */
+ if (!(req->flags & (REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL)))
+ return;
+
+ /*
+ * While we hold the waitqueue lock and the waitqueue is nonempty,
+ * wake_up_pollfree() will wait for us. However, taking the waitqueue
+ * lock in the first place can race with the waitqueue being freed.
+ *
+ * We solve this as eventpoll does: by taking advantage of the fact that
+ * all users of wake_up_pollfree() will RCU-delay the actual free. If
+ * we enter rcu_read_lock() and see that the pointer to the queue is
+ * non-NULL, we can then lock it without the memory being freed out from
+ * under us.
+ *
+ * Keep holding rcu_read_lock() as long as we hold the queue lock, in
+ * case the caller deletes the entry from the queue, leaving it empty.
+ * In that case, only RCU prevents the queue memory from being freed.
+ */
+ rcu_read_lock();
+ if (req->flags & REQ_F_SINGLE_POLL)
+ io_poll_remove_entry(io_poll_get_single(req));
+ if (req->flags & REQ_F_DOUBLE_POLL)
+ io_poll_remove_entry(io_poll_get_double(req));
+ rcu_read_unlock();
+}
+
+/*
+ * All poll tw should go through this. Checks for poll events, manages
+ * references, does rewait, etc.
+ *
+ * Returns a negative error on failure. >0 when no action require, which is
+ * either spurious wakeup or multishot CQE is served. 0 when it's done with
+ * the request, then the mask is stored in req->cqe.res.
+ */
+static int io_poll_check_events(struct io_kiocb *req, bool *locked)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ int v, ret;
+
+ /* req->task == current here, checking PF_EXITING is safe */
+ if (unlikely(req->task->flags & PF_EXITING))
+ return -ECANCELED;
+
+ do {
+ v = atomic_read(&req->poll_refs);
+
+ /* tw handler should be the owner, and so have some references */
+ if (WARN_ON_ONCE(!(v & IO_POLL_REF_MASK)))
+ return 0;
+ if (v & IO_POLL_CANCEL_FLAG)
+ return -ECANCELED;
+
+ if (!req->cqe.res) {
+ struct poll_table_struct pt = { ._key = req->apoll_events };
+ req->cqe.res = vfs_poll(req->file, &pt) & req->apoll_events;
+ }
+
+ if ((unlikely(!req->cqe.res)))
+ continue;
+ if (req->apoll_events & EPOLLONESHOT)
+ return 0;
+
+ /* multishot, just fill a CQE and proceed */
+ if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
+ __poll_t mask = mangle_poll(req->cqe.res &
+ req->apoll_events);
+ bool filled;
+
+ spin_lock(&ctx->completion_lock);
+ filled = io_fill_cqe_aux(ctx, req->cqe.user_data,
+ mask, IORING_CQE_F_MORE);
+ io_commit_cqring(ctx);
+ spin_unlock(&ctx->completion_lock);
+ if (filled) {
+ io_cqring_ev_posted(ctx);
+ continue;
+ }
+ return -ECANCELED;
+ }
+
+ ret = io_poll_issue(req, locked);
+ if (ret)
+ return ret;
+
+ /*
+ * Release all references, retry if someone tried to restart
+ * task_work while we were executing it.
+ */
+ } while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs));
+
+ return 1;
+}
+
+static void io_poll_task_func(struct io_kiocb *req, bool *locked)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ int ret;
+
+ ret = io_poll_check_events(req, locked);
+ if (ret > 0)
+ return;
+
+ if (!ret) {
+ struct io_poll *poll = io_kiocb_to_cmd(req);
+
+ req->cqe.res = mangle_poll(req->cqe.res & poll->events);
+ } else {
+ req->cqe.res = ret;
+ req_set_fail(req);
+ }
+
+ io_poll_remove_entries(req);
+ spin_lock(&ctx->completion_lock);
+ hash_del(&req->hash_node);
+ req->cqe.flags = 0;
+ __io_req_complete_post(req);
+ io_commit_cqring(ctx);
+ spin_unlock(&ctx->completion_lock);
+ io_cqring_ev_posted(ctx);
+}
+
+static void io_apoll_task_func(struct io_kiocb *req, bool *locked)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ int ret;
+
+ ret = io_poll_check_events(req, locked);
+ if (ret > 0)
+ return;
+
+ io_poll_remove_entries(req);
+ spin_lock(&ctx->completion_lock);
+ hash_del(&req->hash_node);
+ spin_unlock(&ctx->completion_lock);
+
+ if (!ret)
+ io_req_task_submit(req, locked);
+ else
+ io_req_complete_failed(req, ret);
+}
+
+static void __io_poll_execute(struct io_kiocb *req, int mask,
+ __poll_t __maybe_unused events)
+{
+ io_req_set_res(req, mask, 0);
+ /*
+ * This is useful for poll that is armed on behalf of another
+ * request, and where the wakeup path could be on a different
+ * CPU. We want to avoid pulling in req->apoll->events for that
+ * case.
+ */
+ if (req->opcode == IORING_OP_POLL_ADD)
+ req->io_task_work.func = io_poll_task_func;
+ else
+ req->io_task_work.func = io_apoll_task_func;
+
+ trace_io_uring_task_add(req->ctx, req, req->cqe.user_data, req->opcode, mask);
+ io_req_task_work_add(req);
+}
+
+static inline void io_poll_execute(struct io_kiocb *req, int res,
+ __poll_t events)
+{
+ if (io_poll_get_ownership(req))
+ __io_poll_execute(req, res, events);
+}
+
+static void io_poll_cancel_req(struct io_kiocb *req)
+{
+ io_poll_mark_cancelled(req);
+ /* kick tw, which should complete the request */
+ io_poll_execute(req, 0, 0);
+}
+
+#define wqe_to_req(wait) ((void *)((unsigned long) (wait)->private & ~1))
+#define wqe_is_double(wait) ((unsigned long) (wait)->private & 1)
+#define IO_ASYNC_POLL_COMMON (EPOLLONESHOT | EPOLLPRI)
+
+static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
+ void *key)
+{
+ struct io_kiocb *req = wqe_to_req(wait);
+ struct io_poll *poll = container_of(wait, struct io_poll, wait);
+ __poll_t mask = key_to_poll(key);
+
+ if (unlikely(mask & POLLFREE)) {
+ io_poll_mark_cancelled(req);
+ /* we have to kick tw in case it's not already */
+ io_poll_execute(req, 0, poll->events);
+
+ /*
+ * If the waitqueue is being freed early but someone is already
+ * holds ownership over it, we have to tear down the request as
+ * best we can. That means immediately removing the request from
+ * its waitqueue and preventing all further accesses to the
+ * waitqueue via the request.
+ */
+ list_del_init(&poll->wait.entry);
+
+ /*
+ * Careful: this *must* be the last step, since as soon
+ * as req->head is NULL'ed out, the request can be
+ * completed and freed, since aio_poll_complete_work()
+ * will no longer need to take the waitqueue lock.
+ */
+ smp_store_release(&poll->head, NULL);
+ return 1;
+ }
+
+ /* for instances that support it check for an event match first */
+ if (mask && !(mask & (poll->events & ~IO_ASYNC_POLL_COMMON)))
+ return 0;
+
+ if (io_poll_get_ownership(req)) {
+ /* optional, saves extra locking for removal in tw handler */
+ if (mask && poll->events & EPOLLONESHOT) {
+ list_del_init(&poll->wait.entry);
+ poll->head = NULL;
+ if (wqe_is_double(wait))
+ req->flags &= ~REQ_F_DOUBLE_POLL;
+ else
+ req->flags &= ~REQ_F_SINGLE_POLL;
+ }
+ __io_poll_execute(req, mask, poll->events);
+ }
+ return 1;
+}
+
+static void __io_queue_proc(struct io_poll *poll, struct io_poll_table *pt,
+ struct wait_queue_head *head,
+ struct io_poll **poll_ptr)
+{
+ struct io_kiocb *req = pt->req;
+ unsigned long wqe_private = (unsigned long) req;
+
+ /*
+ * The file being polled uses multiple waitqueues for poll handling
+ * (e.g. one for read, one for write). Setup a separate io_poll
+ * if this happens.
+ */
+ if (unlikely(pt->nr_entries)) {
+ struct io_poll *first = poll;
+
+ /* double add on the same waitqueue head, ignore */
+ if (first->head == head)
+ return;
+ /* already have a 2nd entry, fail a third attempt */
+ if (*poll_ptr) {
+ if ((*poll_ptr)->head == head)
+ return;
+ pt->error = -EINVAL;
+ return;
+ }
+
+ poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
+ if (!poll) {
+ pt->error = -ENOMEM;
+ return;
+ }
+ /* mark as double wq entry */
+ wqe_private |= 1;
+ req->flags |= REQ_F_DOUBLE_POLL;
+ io_init_poll_iocb(poll, first->events, first->wait.func);
+ *poll_ptr = poll;
+ if (req->opcode == IORING_OP_POLL_ADD)
+ req->flags |= REQ_F_ASYNC_DATA;
+ }
+
+ req->flags |= REQ_F_SINGLE_POLL;
+ pt->nr_entries++;
+ poll->head = head;
+ poll->wait.private = (void *) wqe_private;
+
+ if (poll->events & EPOLLEXCLUSIVE)
+ add_wait_queue_exclusive(head, &poll->wait);
+ else
+ add_wait_queue(head, &poll->wait);
+}
+
+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);
+ struct io_poll *poll = io_kiocb_to_cmd(pt->req);
+
+ __io_queue_proc(poll, pt, head,
+ (struct io_poll **) &pt->req->async_data);
+}
+
+static int __io_arm_poll_handler(struct io_kiocb *req,
+ struct io_poll *poll,
+ struct io_poll_table *ipt, __poll_t mask)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ int v;
+
+ INIT_HLIST_NODE(&req->hash_node);
+ req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
+ io_init_poll_iocb(poll, mask, io_poll_wake);
+ poll->file = req->file;
+
+ req->apoll_events = poll->events;
+
+ ipt->pt._key = mask;
+ ipt->req = req;
+ ipt->error = 0;
+ ipt->nr_entries = 0;
+
+ /*
+ * Take the ownership to delay any tw execution up until we're done
+ * with poll arming. see io_poll_get_ownership().
+ */
+ atomic_set(&req->poll_refs, 1);
+ mask = vfs_poll(req->file, &ipt->pt) & poll->events;
+
+ if (mask && (poll->events & EPOLLONESHOT)) {
+ io_poll_remove_entries(req);
+ /* no one else has access to the req, forget about the ref */
+ return mask;
+ }
+ if (!mask && unlikely(ipt->error || !ipt->nr_entries)) {
+ io_poll_remove_entries(req);
+ if (!ipt->error)
+ ipt->error = -EINVAL;
+ return 0;
+ }
+
+ spin_lock(&ctx->completion_lock);
+ io_poll_req_insert(req);
+ spin_unlock(&ctx->completion_lock);
+
+ if (mask) {
+ /* can't multishot if failed, just queue the event we've got */
+ if (unlikely(ipt->error || !ipt->nr_entries)) {
+ poll->events |= EPOLLONESHOT;
+ req->apoll_events |= EPOLLONESHOT;
+ ipt->error = 0;
+ }
+ __io_poll_execute(req, mask, poll->events);
+ return 0;
+ }
+
+ /*
+ * Release ownership. If someone tried to queue a tw while it was
+ * locked, kick it off for them.
+ */
+ v = atomic_dec_return(&req->poll_refs);
+ if (unlikely(v & IO_POLL_REF_MASK))
+ __io_poll_execute(req, 0, poll->events);
+ return 0;
+}
+
+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);
+}
+
+int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
+{
+ 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 = POLLPRI | POLLERR;
+ int ret;
+
+ if (!def->pollin && !def->pollout)
+ return IO_APOLL_ABORTED;
+ if (!file_can_poll(req->file))
+ return IO_APOLL_ABORTED;
+ if ((req->flags & (REQ_F_POLLED|REQ_F_PARTIAL_IO)) == REQ_F_POLLED)
+ return IO_APOLL_ABORTED;
+ if (!(req->flags & REQ_F_APOLL_MULTISHOT))
+ mask |= EPOLLONESHOT;
+
+ if (def->pollin) {
+ mask |= EPOLLIN | EPOLLRDNORM;
+
+ /* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
+ if (req->flags & REQ_F_CLEAR_POLLIN)
+ mask &= ~EPOLLIN;
+ } else {
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ }
+ if (def->poll_exclusive)
+ mask |= EPOLLEXCLUSIVE;
+ if (req->flags & REQ_F_POLLED) {
+ apoll = req->apoll;
+ kfree(apoll->double_poll);
+ } else if (!(issue_flags & IO_URING_F_UNLOCKED) &&
+ !list_empty(&ctx->apoll_cache)) {
+ apoll = list_first_entry(&ctx->apoll_cache, struct async_poll,
+ poll.wait.entry);
+ list_del_init(&apoll->poll.wait.entry);
+ } else {
+ apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
+ if (unlikely(!apoll))
+ return IO_APOLL_ABORTED;
+ }
+ apoll->double_poll = NULL;
+ req->apoll = apoll;
+ req->flags |= REQ_F_POLLED;
+ ipt.pt._qproc = io_async_queue_proc;
+
+ io_kbuf_recycle(req, issue_flags);
+
+ ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask);
+ if (ret || ipt.error)
+ return ret ? IO_APOLL_READY : IO_APOLL_ABORTED;
+
+ trace_io_uring_poll_arm(ctx, req, req->cqe.user_data, req->opcode,
+ mask, apoll->poll.events);
+ return IO_APOLL_OK;
+}
+
+/*
+ * Returns true if we found and killed one or more poll requests
+ */
+__cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk,
+ bool cancel_all)
+{
+ struct hlist_node *tmp;
+ struct io_kiocb *req;
+ bool found = false;
+ int i;
+
+ spin_lock(&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_safe(req, tsk, cancel_all)) {
+ hlist_del_init(&req->hash_node);
+ io_poll_cancel_req(req);
+ found = true;
+ }
+ }
+ }
+ spin_unlock(&ctx->completion_lock);
+ return found;
+}
+
+static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,
+ struct io_cancel_data *cd)
+ __must_hold(&ctx->completion_lock)
+{
+ struct hlist_head *list;
+ struct io_kiocb *req;
+
+ list = &ctx->cancel_hash[hash_long(cd->data, ctx->cancel_hash_bits)];
+ hlist_for_each_entry(req, list, hash_node) {
+ if (cd->data != req->cqe.user_data)
+ continue;
+ if (poll_only && req->opcode != IORING_OP_POLL_ADD)
+ continue;
+ if (cd->flags & IORING_ASYNC_CANCEL_ALL) {
+ if (cd->seq == req->work.cancel_seq)
+ continue;
+ req->work.cancel_seq = cd->seq;
+ }
+ return req;
+ }
+ return NULL;
+}
+
+static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,
+ struct io_cancel_data *cd)
+ __must_hold(&ctx->completion_lock)
+{
+ struct io_kiocb *req;
+ int i;
+
+ for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
+ struct hlist_head *list;
+
+ list = &ctx->cancel_hash[i];
+ hlist_for_each_entry(req, list, hash_node) {
+ if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) &&
+ req->file != cd->file)
+ continue;
+ if (cd->seq == req->work.cancel_seq)
+ continue;
+ req->work.cancel_seq = cd->seq;
+ return req;
+ }
+ }
+ return NULL;
+}
+
+static bool io_poll_disarm(struct io_kiocb *req)
+ __must_hold(&ctx->completion_lock)
+{
+ if (!io_poll_get_ownership(req))
+ return false;
+ io_poll_remove_entries(req);
+ hash_del(&req->hash_node);
+ return true;
+}
+
+int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
+ __must_hold(&ctx->completion_lock)
+{
+ struct io_kiocb *req;
+
+ if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY))
+ req = io_poll_file_find(ctx, cd);
+ else
+ req = io_poll_find(ctx, false, cd);
+ if (!req)
+ return -ENOENT;
+ io_poll_cancel_req(req);
+ return 0;
+}
+
+static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe,
+ unsigned int flags)
+{
+ u32 events;
+
+ events = READ_ONCE(sqe->poll32_events);
+#ifdef __BIG_ENDIAN
+ events = swahw32(events);
+#endif
+ if (!(flags & IORING_POLL_ADD_MULTI))
+ events |= EPOLLONESHOT;
+ return demangle_poll(events) | (events & (EPOLLEXCLUSIVE|EPOLLONESHOT));
+}
+
+int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+ struct io_poll_update *upd = io_kiocb_to_cmd(req);
+ u32 flags;
+
+ if (sqe->buf_index || sqe->splice_fd_in)
+ return -EINVAL;
+ flags = READ_ONCE(sqe->len);
+ if (flags & ~(IORING_POLL_UPDATE_EVENTS | IORING_POLL_UPDATE_USER_DATA |
+ IORING_POLL_ADD_MULTI))
+ return -EINVAL;
+ /* meaningless without update */
+ if (flags == IORING_POLL_ADD_MULTI)
+ return -EINVAL;
+
+ upd->old_user_data = READ_ONCE(sqe->addr);
+ upd->update_events = flags & IORING_POLL_UPDATE_EVENTS;
+ upd->update_user_data = flags & IORING_POLL_UPDATE_USER_DATA;
+
+ upd->new_user_data = READ_ONCE(sqe->off);
+ if (!upd->update_user_data && upd->new_user_data)
+ return -EINVAL;
+ if (upd->update_events)
+ upd->events = io_poll_parse_events(sqe, flags);
+ else if (sqe->poll32_events)
+ return -EINVAL;
+
+ return 0;
+}
+
+int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+ struct io_poll *poll = io_kiocb_to_cmd(req);
+ u32 flags;
+
+ if (sqe->buf_index || sqe->off || sqe->addr)
+ return -EINVAL;
+ flags = READ_ONCE(sqe->len);
+ if (flags & ~IORING_POLL_ADD_MULTI)
+ return -EINVAL;
+ if ((flags & IORING_POLL_ADD_MULTI) && (req->flags & REQ_F_CQE_SKIP))
+ return -EINVAL;
+
+ io_req_set_refcount(req);
+ poll->events = io_poll_parse_events(sqe, flags);
+ return 0;
+}
+
+int io_poll_add(struct io_kiocb *req, unsigned int issue_flags)
+{
+ struct io_poll *poll = io_kiocb_to_cmd(req);
+ struct io_poll_table ipt;
+ int ret;
+
+ ipt.pt._qproc = io_poll_queue_proc;
+
+ ret = __io_arm_poll_handler(req, poll, &ipt, poll->events);
+ if (ret) {
+ io_req_set_res(req, ret, 0);
+ return IOU_OK;
+ }
+ if (ipt.error) {
+ req_set_fail(req);
+ return ipt.error;
+ }
+
+ return IOU_ISSUE_SKIP_COMPLETE;
+}
+
+int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
+{
+ struct io_poll_update *poll_update = io_kiocb_to_cmd(req);
+ struct io_cancel_data cd = { .data = poll_update->old_user_data, };
+ struct io_ring_ctx *ctx = req->ctx;
+ struct io_kiocb *preq;
+ int ret2, ret = 0;
+ bool locked;
+
+ spin_lock(&ctx->completion_lock);
+ preq = io_poll_find(ctx, true, &cd);
+ if (!preq || !io_poll_disarm(preq)) {
+ spin_unlock(&ctx->completion_lock);
+ ret = preq ? -EALREADY : -ENOENT;
+ goto out;
+ }
+ spin_unlock(&ctx->completion_lock);
+
+ if (poll_update->update_events || poll_update->update_user_data) {
+ /* only mask one event flags, keep behavior flags */
+ if (poll_update->update_events) {
+ struct io_poll *poll = io_kiocb_to_cmd(preq);
+
+ poll->events &= ~0xffff;
+ poll->events |= poll_update->events & 0xffff;
+ poll->events |= IO_POLL_UNMASK;
+ }
+ if (poll_update->update_user_data)
+ preq->cqe.user_data = poll_update->new_user_data;
+
+ ret2 = io_poll_add(preq, issue_flags);
+ /* successfully updated, don't complete poll request */
+ if (!ret2 || ret2 == -EIOCBQUEUED)
+ goto out;
+ }
+
+ req_set_fail(preq);
+ io_req_set_res(preq, -ECANCELED, 0);
+ locked = !(issue_flags & IO_URING_F_UNLOCKED);
+ io_req_task_complete(preq, &locked);
+out:
+ if (ret < 0) {
+ req_set_fail(req);
+ return ret;
+ }
+ /* complete update request, we're done with it */
+ io_req_set_res(req, ret, 0);
+ return IOU_OK;
+}