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path: root/block/blk-wbt.c
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2026-07-01block: Make WBT latency writes honor enable stateGuzebing
queue/wbt_lat_usec controls both the stored WBT latency target and the effective WBT enable state. The old no-op check skipped updates whenever the converted latency matched the stored min_lat_nsec. That check ignored whether the current WBT state already matched the state requested by the write. For a queue disabled by default, attempting to enable WBT by writing the default value through sysfs could return success while the enable state was left unchanged. Treat a write as a no-op only when both the stored latency and the effective WBT enabled state already match the converted value. Signed-off-by: Guzebing <guzebing1612@gmail.com> Link: https://patch.msgid.link/20260621014030.1625306-1-guzebing1612@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-06blk-wbt: remove WARN_ON_ONCE from wbt_init_enable_default()Yuto Ohnuki
wbt_init_enable_default() uses WARN_ON_ONCE to check for failures from wbt_alloc() and wbt_init(). However, both are expected failure paths: - wbt_alloc() can return NULL under memory pressure (-ENOMEM) - wbt_init() can fail with -EBUSY if wbt is already registered syzbot triggers this by injecting memory allocation failures during MTD partition creation via ioctl(BLKPG), causing a spurious warning. wbt_init_enable_default() is a best-effort initialization called from blk_register_queue() with a void return type. Failure simply means the disk operates without writeback throttling, which is harmless. Replace WARN_ON_ONCE with plain if-checks, consistent with how wbt_set_lat() in the same file already handles these failures. Add a pr_warn() for the wbt_init() failure to retain diagnostic information without triggering a full stack trace. Reported-by: syzbot+71fcf20f7c1e5043d78c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=71fcf20f7c1e5043d78c Fixes: 41afaeeda509 ("blk-wbt: fix possible deadlock to nest pcpu_alloc_mutex under q_usage_counter") Signed-off-by: Yuto Ohnuki <ytohnuki@amazon.com> Reviewed-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Link: https://patch.msgid.link/20260316070358.65225-2-ytohnuki@amazon.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-21Convert 'alloc_obj' family to use the new default GFP_KERNEL argumentLinus Torvalds
This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21treewide: Replace kmalloc with kmalloc_obj for non-scalar typesKees Cook
This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-16blk-mq: use NOIO context to prevent deadlock during debugfs creationYu Kuai
Creating debugfs entries can trigger fs reclaim, which can enter back into the block layer request_queue. This can cause deadlock if the queue is frozen. Previously, a WARN_ON_ONCE check was used in debugfs_create_files() to detect this condition, but it was racy since the queue can be frozen from another context at any time. Introduce blk_debugfs_lock()/blk_debugfs_unlock() helpers that combine the debugfs_mutex with memalloc_noio_save()/restore() to prevent fs reclaim from triggering block I/O. Also add blk_debugfs_lock_nomemsave() and blk_debugfs_unlock_nomemrestore() variants for callers that don't need NOIO protection (e.g., debugfs removal or read-only operations). Replace all raw debugfs_mutex lock/unlock pairs with these helpers, using the _nomemsave/_nomemrestore variants where appropriate. Reported-by: Yi Zhang <yi.zhang@redhat.com> Closes: https://lore.kernel.org/all/CAHj4cs9gNKEYAPagD9JADfO5UH+OiCr4P7OO2wjpfOYeM-RV=A@mail.gmail.com/ Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com> Closes: https://lore.kernel.org/all/aYWQR7CtYdk3K39g@shinmob/ Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-02blk-rq-qos: fix possible debugfs_mutex deadlockYu Kuai
Currently rq-qos debugfs entries are created from rq_qos_add(), while rq_qos_add() can be called while queue is still frozen. This can deadlock because creating new entries can trigger fs reclaim. Fix this problem by delaying creating rq-qos debugfs entries after queue is unfrozen. - For wbt, 1) it can be initialized by default, fix it by calling new helper after wbt_init() from wbt_init_enable_default(); 2) it can be initialized by sysfs, fix it by calling new helper after queue is unfrozen from wbt_set_lat(). - For iocost and iolatency, they can only be initialized by blkcg configuration, however, they don't have debugfs entries for now, hence they are not handled yet. Signed-off-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-02blk-wbt: fix possible deadlock to nest pcpu_alloc_mutex under q_usage_counterYu Kuai
If wbt is disabled by default and user configures wbt by sysfs, queue will be frozen first and then pcpu_alloc_mutex will be held in blk_stat_alloc_callback(). Fix this problem by allocating memory first before queue frozen. Signed-off-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-02blk-wbt: factor out a helper wbt_set_lat()Yu Kuai
To move implementation details inside blk-wbt.c, prepare to fix possible deadlock to call wbt_init() while queue is frozen in the next patch. Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Signed-off-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-29block: introduce blk_queue_rot()Damien Le Moal
To check if a request queue is for a rotational device, a double negation is needed with the pattern "!blk_queue_nonrot(q)". Simplify this with the introduction of the helper blk_queue_rot() which tests if a requests queue limit has the BLK_FEAT_ROTATIONAL feature set. All call sites of blk_queue_nonrot() are modified to use blk_queue_rot() and blk_queue_nonrot() definition removed. No functional changes. Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-12-12block: fix race between wbt_enable_default and IO submissionMing Lei
When wbt_enable_default() is moved out of queue freezing in elevator_change(), it can cause the wbt inflight counter to become negative (-1), leading to hung tasks in the writeback path. Tasks get stuck in wbt_wait() because the counter is in an inconsistent state. The issue occurs because wbt_enable_default() could race with IO submission, allowing the counter to be decremented before proper initialization. This manifests as: rq_wait[0]: inflight: -1 has_waiters: True rwb_enabled() checks the state, which can be updated exactly between wbt_wait() (rq_qos_throttle()) and wbt_track()(rq_qos_track()), then the inflight counter will become negative. And results in hung task warnings like: task:kworker/u24:39 state:D stack:0 pid:14767 Call Trace: rq_qos_wait+0xb4/0x150 wbt_wait+0xa9/0x100 __rq_qos_throttle+0x24/0x40 blk_mq_submit_bio+0x672/0x7b0 ... Fix this by: 1. Splitting wbt_enable_default() into: - __wbt_enable_default(): Returns true if wbt_init() should be called - wbt_enable_default(): Wrapper for existing callers (no init) - wbt_init_enable_default(): New function that checks and inits WBT 2. Using wbt_init_enable_default() in blk_register_queue() to ensure proper initialization during queue registration 3. Move wbt_init() out of wbt_enable_default() which is only for enabling disabled wbt from bfq and iocost, and wbt_init() isn't needed. Then the original lock warning can be avoided. 4. Removing the ELEVATOR_FLAG_ENABLE_WBT_ON_EXIT flag and its handling code since it's no longer needed This ensures WBT is properly initialized before any IO can be submitted, preventing the counter from going negative. Cc: Nilay Shroff <nilay@linux.ibm.com> Cc: Yu Kuai <yukuai@fnnas.com> Cc: Guangwu Zhang <guazhang@redhat.com> Fixes: 78c271344b6f ("block: move wbt_enable_default() out of queue freezing from sched ->exit()") Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-11blk-wbt: Eliminate ambiguity in the comments of struct rq_wbTang Yizhou
In the current implementation, the last_issue and last_comp members of struct rq_wb are used only by read requests and not by non-throttled write requests. Therefore, eliminate the ambiguity here. Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20250727173959.160835-3-yizhou.tang@shopee.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-11blk-wbt: Optimize wbt_done() for non-throttled writesTang Yizhou
In the current implementation, the sync_cookie and last_cookie members of struct rq_wb are used only by read requests and not by non-throttled write requests. Based on this, we can optimize wbt_done() by removing one if condition check for non-throttled write requests. Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20250727173959.160835-2-yizhou.tang@shopee.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-26Merge tag 'for-6.16/block-20250523' of git://git.kernel.dk/linuxLinus Torvalds
Pull block updates from Jens Axboe: - ublk updates: - Add support for updating the size of a ublk instance - Zero-copy improvements - Auto-registering of buffers for zero-copy - Series simplifying and improving GET_DATA and request lookup - Series adding quiesce support - Lots of selftests additions - Various cleanups - NVMe updates via Christoph: - add per-node DMA pools and use them for PRP/SGL allocations (Caleb Sander Mateos, Keith Busch) - nvme-fcloop refcounting fixes (Daniel Wagner) - support delayed removal of the multipath node and optionally support the multipath node for private namespaces (Nilay Shroff) - support shared CQs in the PCI endpoint target code (Wilfred Mallawa) - support admin-queue only authentication (Hannes Reinecke) - use the crc32c library instead of the crypto API (Eric Biggers) - misc cleanups (Christoph Hellwig, Marcelo Moreira, Hannes Reinecke, Leon Romanovsky, Gustavo A. R. Silva) - MD updates via Yu: - Fix that normal IO can be starved by sync IO, found by mkfs on newly created large raid5, with some clean up patches for bdev inflight counters - Clean up brd, getting rid of atomic kmaps and bvec poking - Add loop driver specifically for zoned IO testing - Eliminate blk-rq-qos calls with a static key, if not enabled - Improve hctx locking for when a plug has IO for multiple queues pending - Remove block layer bouncing support, which in turn means we can remove the per-node bounce stat as well - Improve blk-throttle support - Improve delay support for blk-throttle - Improve brd discard support - Unify IO scheduler switching. This should also fix a bunch of lockdep warnings we've been seeing, after enabling lockdep support for queue freezing/unfreezeing - Add support for block write streams via FDP (flexible data placement) on NVMe - Add a bunch of block helpers, facilitating the removal of a bunch of duplicated boilerplate code - Remove obsolete BLK_MQ pci and virtio Kconfig options - Add atomic/untorn write support to blktrace - Various little cleanups and fixes * tag 'for-6.16/block-20250523' of git://git.kernel.dk/linux: (186 commits) selftests: ublk: add test for UBLK_F_QUIESCE ublk: add feature UBLK_F_QUIESCE selftests: ublk: add test case for UBLK_U_CMD_UPDATE_SIZE traceevent/block: Add REQ_ATOMIC flag to block trace events ublk: run auto buf unregisgering in same io_ring_ctx with registering io_uring: add helper io_uring_cmd_ctx_handle() ublk: remove io argument from ublk_auto_buf_reg_fallback() ublk: handle ublk_set_auto_buf_reg() failure correctly in ublk_fetch() selftests: ublk: add test for covering UBLK_AUTO_BUF_REG_FALLBACK selftests: ublk: support UBLK_F_AUTO_BUF_REG ublk: support UBLK_AUTO_BUF_REG_FALLBACK ublk: register buffer to local io_uring with provided buf index via UBLK_F_AUTO_BUF_REG ublk: prepare for supporting to register request buffer automatically ublk: convert to refcount_t selftests: ublk: make IO & device removal test more stressful nvme: rename nvme_mpath_shutdown_disk to nvme_mpath_remove_disk nvme: introduce multipath_always_on module param nvme-multipath: introduce delayed removal of the multipath head node nvme-pci: derive and better document max segments limits nvme-pci: use struct_size for allocation struct nvme_dev ...
2025-05-06block: move wbt_enable_default() out of queue freezing from sched ->exit()Ming Lei
scheduler's ->exit() is called with queue frozen and elevator lock is held, and wbt_enable_default() can't be called with queue frozen, otherwise the following lockdep warning is triggered: #6 (&q->rq_qos_mutex){+.+.}-{4:4}: #5 (&eq->sysfs_lock){+.+.}-{4:4}: #4 (&q->elevator_lock){+.+.}-{4:4}: #3 (&q->q_usage_counter(io)#3){++++}-{0:0}: #2 (fs_reclaim){+.+.}-{0:0}: #1 (&sb->s_type->i_mutex_key#3){+.+.}-{4:4}: #0 (&q->debugfs_mutex){+.+.}-{4:4}: Fix the issue by moving wbt_enable_default() out of bfq's exit(), and call it from elevator_change_done(). Meantime add disk->rqos_state_mutex for covering wbt state change, which matches the purpose more than ->elevator_lock. Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250505141805.2751237-26-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-06block: move ELEVATOR_FLAG_DISABLE_WBT a request queue flagMing Lei
ELEVATOR_FLAG_DISABLE_WBT is only used by BFQ to disallow wbt when BFQ is in use. The flag is set in BFQ's init(), and cleared in BFQ's exit(). Making it as request queue flag, so that we can avoid to deal with elevator switch race. Also it isn't graceful to checking one scheduler flag in wbt_enable_default(). Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20250505141805.2751237-3-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07mm: Remove swap_writepage() and shmem_writepage()Matthew Wilcox (Oracle)
Call swap_writeout() and shmem_writeout() from pageout() instead. Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org> Link: https://lore.kernel.org/r/20250402150005.2309458-9-willy@infradead.org Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-25blk-wbt: Cleanup a comment in wb_timer_fnTang Yizhou
The original comment contains a grammatical error. Rewrite it into a more easily understandable sentence. Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com> Link: https://lore.kernel.org/r/20250213100611.209997-3-yizhou.tang@shopee.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-25blk-wbt: Fix some commentsTang Yizhou
wbt_wait() no longer uses a spinlock as a parameter. Update the function comments accordingly. RWB_UNKNOWN_BUMP is used when we gradually adjust scale_steps toward the center state, which is a value of 0. Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20250213100611.209997-2-yizhou.tang@shopee.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-07-01blk-wbt: don't throttle swap writes in direct reclaimBaokun Li
Now we avoid throttling swap writes by determining whether the current process is kswapd (aka current_is_kswapd()), but swap writes can come from either kswapd or direct reclaim, so the swap writes from direct reclaim will still be throttled. When a process holds a lock to allocate a free page, and enters direct reclaim because there is no free memory, then it might trigger a hung due to the wbt throttling that causes other processes to fail to get the lock. Both kswapd and direct reclaim set the REQ_SWAP flag, so use REQ_SWAP instead of current_is_kswapd() to avoid throttling swap writes. Also renamed WBT_KSWAPD to WBT_SWAP and WBT_RWQ_KSWAPD to WBT_RWQ_SWAP. Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20240604030522.3686177-1-libaokun@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-19block: move cache control settings out of queue->flagsChristoph Hellwig
Move the cache control settings into the queue_limits so that the flags can be set atomically with the device queue frozen. Add new features and flags field for the driver set flags, and internal (usually sysfs-controlled) flags in the block layer. Note that we'll eventually remove enough field from queue_limits to bring it back to the previous size. The disable flag is inverted compared to the previous meaning, which means it now survives a rescan, similar to the max_sectors and max_discard_sectors user limits. The FLUSH and FUA flags are now inherited by blk_stack_limits, which simplified the code in dm a lot, but also causes a slight behavior change in that dm-switch and dm-unstripe now advertise a write cache despite setting num_flush_bios to 0. The I/O path will handle this gracefully, but as far as I can tell the lack of num_flush_bios and thus flush support is a pre-existing data integrity bug in those targets that really needs fixing, after which a non-zero num_flush_bios should be required in dm for targets that map to underlying devices. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20240617060532.127975-14-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-03-11Merge tag 'for-6.9/block-20240310' of git://git.kernel.dk/linuxLinus Torvalds
Pull block updates from Jens Axboe: - MD pull requests via Song: - Cleanup redundant checks (Yu Kuai) - Remove deprecated headers (Marc Zyngier, Song Liu) - Concurrency fixes (Li Lingfeng) - Memory leak fix (Li Nan) - Refactor raid1 read_balance (Yu Kuai, Paul Luse) - Clean up and fix for md_ioctl (Li Nan) - Other small fixes (Gui-Dong Han, Heming Zhao) - MD atomic limits (Christoph) - NVMe pull request via Keith: - RDMA target enhancements (Max) - Fabrics fixes (Max, Guixin, Hannes) - Atomic queue_limits usage (Christoph) - Const use for class_register (Ricardo) - Identification error handling fixes (Shin'ichiro, Keith) - Improvement and cleanup for cached request handling (Christoph) - Moving towards atomic queue limits. Core changes and driver bits so far (Christoph) - Fix UAF issues in aoeblk (Chun-Yi) - Zoned fix and cleanups (Damien) - s390 dasd cleanups and fixes (Jan, Miroslav) - Block issue timestamp caching (me) - noio scope guarding for zoned IO (Johannes) - block/nvme PI improvements (Kanchan) - Ability to terminate long running discard loop (Keith) - bdev revalidation fix (Li) - Get rid of old nr_queues hack for kdump kernels (Ming) - Support for async deletion of ublk (Ming) - Improve IRQ bio recycling (Pavel) - Factor in CPU capacity for remote vs local completion (Qais) - Add shared_tags configfs entry for null_blk (Shin'ichiro - Fix for a regression in page refcounts introduced by the folio unification (Tony) - Misc fixes and cleanups (Arnd, Colin, John, Kunwu, Li, Navid, Ricardo, Roman, Tang, Uwe) * tag 'for-6.9/block-20240310' of git://git.kernel.dk/linux: (221 commits) block: partitions: only define function mac_fix_string for CONFIG_PPC_PMAC block/swim: Convert to platform remove callback returning void cdrom: gdrom: Convert to platform remove callback returning void block: remove disk_stack_limits md: remove mddev->queue md: don't initialize queue limits md/raid10: use the atomic queue limit update APIs md/raid5: use the atomic queue limit update APIs md/raid1: use the atomic queue limit update APIs md/raid0: use the atomic queue limit update APIs md: add queue limit helpers md: add a mddev_is_dm helper md: add a mddev_add_trace_msg helper md: add a mddev_trace_remap helper bcache: move calculation of stripe_size and io_opt into bcache_device_init virtio_blk: Do not use disk_set_max_open/active_zones() aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts block: move capacity validation to blkpg_do_ioctl() block: prevent division by zero in blk_rq_stat_sum() drbd: atomically update queue limits in drbd_reconsider_queue_parameters ...
2024-02-06blk-wbt: Fix detection of dirty-throttled tasksJan Kara
The detection of dirty-throttled tasks in blk-wbt has been subtly broken since its beginning in 2016. Namely if we are doing cgroup writeback and the throttled task is not in the root cgroup, balance_dirty_pages() will set dirty_sleep for the non-root bdi_writeback structure. However blk-wbt checks dirty_sleep only in the root cgroup bdi_writeback structure. Thus detection of recently throttled tasks is not working in this case (we noticed this when we switched to cgroup v2 and suddently writeback was slow). Since blk-wbt has no easy way to get to proper bdi_writeback and furthermore its intention has always been to work on the whole device rather than on individual cgroups, just move the dirty_sleep timestamp from bdi_writeback to backing_dev_info. That fixes the checking for recently throttled task and saves memory for everybody as a bonus. CC: stable@vger.kernel.org Fixes: b57d74aff9ab ("writeback: track if we're sleeping on progress in balance_dirty_pages()") Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20240123175826.21452-1-jack@suse.cz [axboe: fixup indentation errors] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-02-05block: add blk_time_get_ns() and blk_time_get() helpersJens Axboe
Convert any user of ktime_get_ns() to use blk_time_get_ns(), and ktime_get() to blk_time_get(), so we have a unified API for querying the current time in nanoseconds or as ktime. No functional changes intended, this patch just wraps ktime_get_ns() and ktime_get() with a block helper. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-12-26blk-wbt: remove the separate write cache trackingChristoph Hellwig
Use the queue wide write back cache tracking insted of duplicating the value in strut rq_wb. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231226090747.204969-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-28Merge branch 'for-6.5/block-late' into block-6.5Jens Axboe
* for-6.5/block-late: blk-sysfs: add a new attr_group for blk_mq blk-iocost: move wbt_enable/disable_default() out of spinlock blk-wbt: cleanup rwb_enabled() and wbt_disabled() blk-wbt: remove dead code to handle wbt enable/disable with io inflight blk-wbt: don't create wbt sysfs entry if CONFIG_BLK_WBT is disabled blk-mq: fix two misuses on RQF_USE_SCHED blk-throttle: Fix io statistics for cgroup v1 bcache: Fix bcache device claiming bcache: Alloc holder object before async registration raid10: avoid spin_lock from fastpath from raid10_unplug() md: fix 'delete_mutex' deadlock md: use mddev->external to select holder in export_rdev() md/raid1-10: fix casting from randomized structure in raid1_submit_write() md/raid10: fix the condition to call bio_end_io_acct()
2023-06-26Merge tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linuxLinus Torvalds
Pull block updates from Jens Axboe: - NVMe pull request via Keith: - Various cleanups all around (Irvin, Chaitanya, Christophe) - Better struct packing (Christophe JAILLET) - Reduce controller error logs for optional commands (Keith) - Support for >=64KiB block sizes (Daniel Gomez) - Fabrics fixes and code organization (Max, Chaitanya, Daniel Wagner) - bcache updates via Coly: - Fix a race at init time (Mingzhe Zou) - Misc fixes and cleanups (Andrea, Thomas, Zheng, Ye) - use page pinning in the block layer for dio (David) - convert old block dio code to page pinning (David, Christoph) - cleanups for pktcdvd (Andy) - cleanups for rnbd (Guoqing) - use the unchecked __bio_add_page() for the initial single page additions (Johannes) - fix overflows in the Amiga partition handling code (Michael) - improve mq-deadline zoned device support (Bart) - keep passthrough requests out of the IO schedulers (Christoph, Ming) - improve support for flush requests, making them less special to deal with (Christoph) - add bdev holder ops and shutdown methods (Christoph) - fix the name_to_dev_t() situation and use cases (Christoph) - decouple the block open flags from fmode_t (Christoph) - ublk updates and cleanups, including adding user copy support (Ming) - BFQ sanity checking (Bart) - convert brd from radix to xarray (Pankaj) - constify various structures (Thomas, Ivan) - more fine grained persistent reservation ioctl capability checks (Jingbo) - misc fixes and cleanups (Arnd, Azeem, Demi, Ed, Hengqi, Hou, Jan, Jordy, Li, Min, Yu, Zhong, Waiman) * tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux: (266 commits) scsi/sg: don't grab scsi host module reference ext4: Fix warning in blkdev_put() block: don't return -EINVAL for not found names in devt_from_devname cdrom: Fix spectre-v1 gadget block: Improve kernel-doc headers blk-mq: don't insert passthrough request into sw queue bsg: make bsg_class a static const structure ublk: make ublk_chr_class a static const structure aoe: make aoe_class a static const structure block/rnbd: make all 'class' structures const block: fix the exclusive open mask in disk_scan_partitions block: add overflow checks for Amiga partition support block: change all __u32 annotations to __be32 in affs_hardblocks.h block: fix signed int overflow in Amiga partition support block: add capacity validation in bdev_add_partition() block: fine-granular CAP_SYS_ADMIN for Persistent Reservation block: disallow Persistent Reservation on partitions reiserfs: fix blkdev_put() warning from release_journal_dev() block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions() block: document the holder argument to blkdev_get_by_path ...
2023-06-26blk-wbt: cleanup rwb_enabled() and wbt_disabled()Yu Kuai
'wb_normal' will set to 0 if 'min_lat_nsec' is 0, and 'min_lat_nsec' can only be set to 0 through sysfs configuration where 'WBT_STATE_OFF_MANUAL' is set together, in the meantime, they can only be cleared together through sysfs afterwards. Hence 'wb_normal != 0' is the same as 'rwb->enable_state != WBT_STATE_OFF_MANUAL'. The code is redundan, hence replace the checking of 'wb_normal' to 'enable_state' in rwb_enabled() and reuse rwb_enabled() for wbt_disabled(). Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230527010644.647900-4-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-26blk-wbt: remove dead code to handle wbt enable/disable with io inflightYu Kuai
enable or disable wbt is always called with queue freezed, so that wbt can never be enabled or disabled while io is still inflight, and this behaviour should always hold to avoid io hang(There have been reported several times). Therefor, the code to handle wbt enable/diskble with io inflight is not and never will be used, hence remove such dead code. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230527010644.647900-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-05-23block/rq_qos: protect rq_qos apis with a new lockYu Kuai
commit 50e34d78815e ("block: disable the elevator int del_gendisk") move rq_qos_exit() from disk_release() to del_gendisk(), this will introduce some problems: 1) If rq_qos_add() is triggered by enabling iocost/iolatency through cgroupfs, then it can concurrent with del_gendisk(), it's not safe to write 'q->rq_qos' concurrently. 2) Activate cgroup policy that is relied on rq_qos will call rq_qos_add() and blkcg_activate_policy(), and if rq_qos_exit() is called in the middle, null-ptr-dereference will be triggered in blkcg_activate_policy(). 3) blkg_conf_open_bdev() can call blkdev_get_no_open() first to find the disk, then if rq_qos_exit() from del_gendisk() is done before rq_qos_add(), then memory will be leaked. This patch add a new disk level mutex 'rq_qos_mutex': 1) The lock will protect rq_qos_exit() directly. 2) For wbt that doesn't relied on blk-cgroup, rq_qos_add() can only be called from disk initialization for now because wbt can't be destructed until rq_qos_exit(), so it's safe not to protect wbt for now. Hoever, in case that rq_qos dynamically destruction is supported in the furture, this patch also protect rq_qos_add() from wbt_init() directly, this is enough because blk-sysfs already synchronize writers with disk removal. 3) For iocost and iolatency, in order to synchronize disk removal and cgroup configuration, the lock is held after blkdev_get_no_open() from blkg_conf_open_bdev(), and is released in blkg_conf_exit(). In order to fix the above memory leak, disk_live() is checked after holding the new lock. Fixes: 50e34d78815e ("block: disable the elevator int del_gendisk") Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230414084008.2085155-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-05-23blk-wbt: fix that wbt can't be disabled by defaultYu Kuai
commit b11d31ae01e6 ("blk-wbt: remove unnecessary check in wbt_enable_default()") removes the checking of CONFIG_BLK_WBT_MQ by mistake, which is used to control enable or disable wbt by default. Fix the problem by adding back the checking. This patch also do a litter cleanup to make related code more readable. Fixes: b11d31ae01e6 ("blk-wbt: remove unnecessary check in wbt_enable_default()") Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Link: https://lore.kernel.org/lkml/CAKXUXMzfKq_J9nKHGyr5P5rvUETY4B-fxoQD4sO+NYjFOfVtZA@mail.gmail.com/t/ Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230522121854.2928880-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-rq-qos: store a gendisk instead of request_queue in struct rq_qosChristoph Hellwig
This is what about half of the users already want, and it's only going to grow more. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-16-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-rq-qos: constify rq_qos_opsChristoph Hellwig
These op vectors are constant, so mark them const. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-15-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-rq-qos: make rq_qos_add and rq_qos_del more usefulChristoph Hellwig
Switch to passing a gendisk, and make rq_qos_add initialize all required fields and drop the not required q argument from rq_qos_del. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-14-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-wbt: open code wbt_queue_depth_changed in wbt_initChristoph Hellwig
wbt_queue_depth_changed just updates a field and calls another function. Open code it in wbt_init, so that the local queue variable can be used instead of the one stored in the rq_qos. This will allow delaying that rq_qos->queue assignment in a subsequent patch. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-12-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-wbt: move private information from blk-wbt.h to blk-wbt.cChristoph Hellwig
A large part of blk-wbt.h is only used in blk-wbt.c, so move it there. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-11-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-wbt: pass a gendisk to wbt_initChristoph Hellwig
Pass a gendisk to wbt_init to prepare for phasing out usage of the request_queue in the blk-cgroup code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-10-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-wbt: pass a gendisk to wbt_{enable,disable}_defaultChristoph Hellwig
Pass a gendisk to wbt_enable_default and wbt_disable_default to prepare for phasing out usage of the request_queue in the blk-cgroup code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23blk-wbt: don't enable throttling if default elevator is bfqYu Kuai
Commit b5dc5d4d1f4f ("block,bfq: Disable writeback throttling") tries to disable wbt for bfq, it's done by calling wbt_disable_default() in bfq_init_queue(). However, wbt is still enabled if default elevator is bfq: device_add_disk elevator_init_mq bfq_init_queue wbt_disable_default -> done nothing blk_register_queue wbt_enable_default -> wbt is enabled Fix the problem by adding a new flag ELEVATOR_FLAG_DISBALE_WBT, bfq will set the flag in bfq_init_queue, and following wbt_enable_default() won't enable wbt while the flag is set. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221019121518.3865235-7-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23blk-wbt: don't show valid wbt_lat_usec in sysfs while wbt is disabledYu Kuai
Currently, if wbt is initialized and then disabled by wbt_disable_default(), sysfs will still show valid wbt_lat_usec, which will confuse users that wbt is still enabled. This patch shows wbt_lat_usec as zero if it's disabled. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reported-and-tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221019121518.3865235-5-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23blk-wbt: make enable_state more accurateYu Kuai
Currently, if user disable wbt through sysfs, 'enable_state' will be 'WBT_STATE_ON_MANUAL', which will be confusing. Add a new state 'WBT_STATE_OFF_MANUAL' to cover that case. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221019121518.3865235-4-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23blk-wbt: remove unnecessary check in wbt_enable_default()Yu Kuai
If CONFIG_BLK_WBT_MQ is disabled, wbt_init() won't do anything. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221019121518.3865235-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-09blk-wbt: fix that 'rwb->wc' is always set to 1 in wbt_init()Yu Kuai
commit 8c5035dfbb94 ("blk-wbt: call rq_qos_add() after wb_normal is initialized") moves wbt_set_write_cache() before rq_qos_add(), which is wrong because wbt_rq_qos() is still NULL. Fix the problem by removing wbt_set_write_cache() and setting 'rwb->wc' directly. Noted that this patch also remove the redundant setting of 'rab->wc'. Fixes: 8c5035dfbb94 ("blk-wbt: call rq_qos_add() after wb_normal is initialized") Reported-by: kernel test robot <yujie.liu@intel.com> Link: https://lore.kernel.org/r/202210081045.77ddf59b-yujie.liu@intel.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20221009101038.1692875-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-21blk-wbt: call rq_qos_add() after wb_normal is initializedYu Kuai
Our test found a problem that wbt inflight counter is negative, which will cause io hang(noted that this problem doesn't exist in mainline): t1: device create t2: issue io add_disk blk_register_queue wbt_enable_default wbt_init rq_qos_add // wb_normal is still 0 /* * in mainline, disk can't be opened before * bdev_add(), however, in old kernels, disk * can be opened before blk_register_queue(). */ blkdev_issue_flush // disk size is 0, however, it's not checked submit_bio_wait submit_bio blk_mq_submit_bio rq_qos_throttle wbt_wait bio_to_wbt_flags rwb_enabled // wb_normal is 0, inflight is not increased wbt_queue_depth_changed(&rwb->rqos); wbt_update_limits // wb_normal is initialized rq_qos_track wbt_track rq->wbt_flags |= bio_to_wbt_flags(rwb, bio); // wb_normal is not 0，wbt_flags will be set t3: io completion blk_mq_free_request rq_qos_done wbt_done wbt_is_tracked // return true __wbt_done wbt_rqw_done atomic_dec_return(&rqw->inflight); // inflight is decreased commit 8235b5c1e8c1 ("block: call bdev_add later in device_add_disk") can avoid this problem, however it's better to fix this problem in wbt: 1) Lower kernel can't backport this patch due to lots of refactor. 2) Root cause is that wbt call rq_qos_add() before wb_normal is initialized. Fixes: e34cbd307477 ("blk-wbt: add general throttling mechanism") Cc: <stable@vger.kernel.org> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20220913105749.3086243-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-20block: don't allow the same type rq_qos add more than onceJinke Han
In our test of iocost, we encountered some list add/del corruptions of inner_walk list in ioc_timer_fn. The reason can be described as follows: cpu 0 cpu 1 ioc_qos_write ioc_qos_write ioc = q_to_ioc(queue); if (!ioc) { ioc = kzalloc(); ioc = q_to_ioc(queue); if (!ioc) { ioc = kzalloc(); ... rq_qos_add(q, rqos); } ... rq_qos_add(q, rqos); ... } When the io.cost.qos file is written by two cpus concurrently, rq_qos may be added to one disk twice. In that case, there will be two iocs enabled and running on one disk. They own different iocgs on their active list. In the ioc_timer_fn function, because of the iocgs from two iocs have the same root iocg, the root iocg's walk_list may be overwritten by each other and this leads to list add/del corruptions in building or destroying the inner_walk list. And so far, the blk-rq-qos framework works in case that one instance for one type rq_qos per queue by default. This patch make this explicit and also fix the crash above. Signed-off-by: Jinke Han <hanjinke.666@bytedance.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20220720093616.70584-1-hanjinke.666@bytedance.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-14block: Use the new blk_opf_t typeBart Van Assche
Use the new blk_opf_t type for arguments and variables that represent request flags or a bitwise combination of a request operation and request flags. Rename the function arguments and also a structure member that hold a request operation and flags from 'rw' into 'opf'. This patch does not change any functionality. Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20220714180729.1065367-7-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-14block: Use enum req_op where appropriateBart Van Assche
Change the type of the arguments that are used to pass a REQ_OP_* value from int or unsigned int into enum req_op to improve static type checking. Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20220714180729.1065367-3-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19blk-wbt: prevent NULL pointer dereference in wb_timer_fnAndrea Righi
The timer callback used to evaluate if the latency is exceeded can be executed after the corresponding disk has been released, causing the following NULL pointer dereference: [ 119.987108] BUG: kernel NULL pointer dereference, address: 0000000000000098 [ 119.987617] #PF: supervisor read access in kernel mode [ 119.987971] #PF: error_code(0x0000) - not-present page [ 119.988325] PGD 7c4a4067 P4D 7c4a4067 PUD 7bf63067 PMD 0 [ 119.988697] Oops: 0000 [#1] SMP NOPTI [ 119.988959] CPU: 1 PID: 9353 Comm: cloud-init Not tainted 5.15-rc5+arighi #rc5+arighi [ 119.989520] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 [ 119.990055] RIP: 0010:wb_timer_fn+0x44/0x3c0 [ 119.990376] Code: 41 8b 9c 24 98 00 00 00 41 8b 94 24 b8 00 00 00 41 8b 84 24 d8 00 00 00 4d 8b 74 24 28 01 d3 01 c3 49 8b 44 24 60 48 8b 40 78 <4c> 8b b8 98 00 00 00 4d 85 f6 0f 84 c4 00 00 00 49 83 7c 24 30 00 [ 119.991578] RSP: 0000:ffffb5f580957da8 EFLAGS: 00010246 [ 119.991937] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000004 [ 119.992412] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88f476d7f780 [ 119.992895] RBP: ffffb5f580957dd0 R08: 0000000000000000 R09: 0000000000000000 [ 119.993371] R10: 0000000000000004 R11: 0000000000000002 R12: ffff88f476c84500 [ 119.993847] R13: ffff88f4434390c0 R14: 0000000000000000 R15: ffff88f4bdc98c00 [ 119.994323] FS: 00007fb90bcd9c00(0000) GS:ffff88f4bdc80000(0000) knlGS:0000000000000000 [ 119.994952] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 119.995380] CR2: 0000000000000098 CR3: 000000007c0d6000 CR4: 00000000000006e0 [ 119.995906] Call Trace: [ 119.996130] ? blk_stat_free_callback_rcu+0x30/0x30 [ 119.996505] blk_stat_timer_fn+0x138/0x140 [ 119.996830] call_timer_fn+0x2b/0x100 [ 119.997136] __run_timers.part.0+0x1d1/0x240 [ 119.997470] ? kvm_clock_get_cycles+0x11/0x20 [ 119.997826] ? ktime_get+0x3e/0xa0 [ 119.998110] ? native_apic_msr_write+0x2c/0x30 [ 119.998456] ? lapic_next_event+0x20/0x30 [ 119.998779] ? clockevents_program_event+0x94/0xf0 [ 119.999150] run_timer_softirq+0x2a/0x50 [ 119.999465] __do_softirq+0xcb/0x26f [ 119.999764] irq_exit_rcu+0x8c/0xb0 [ 120.000057] sysvec_apic_timer_interrupt+0x43/0x90 [ 120.000429] ? asm_sysvec_apic_timer_interrupt+0xa/0x20 [ 120.000836] asm_sysvec_apic_timer_interrupt+0x12/0x20 In this case simply return from the timer callback (no action required) to prevent the NULL pointer dereference. BugLink: https://bugs.launchpad.net/bugs/1947557 Link: https://lore.kernel.org/linux-mm/YWRNVTk9N8K0RMst@arighi-desktop/ Fixes: 34dbad5d26e2 ("blk-stat: convert to callback-based statistics reporting") Signed-off-by: Andrea Righi <andrea.righi@canonical.com> Link: https://lore.kernel.org/r/YW6N2qXpBU3oc50q@arighi-desktop Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: add an explicit ->disk backpointer to the request_queueChristoph Hellwig
Replace the magic lookup through the kobject tree with an explicit backpointer, given that the device model links are set up and torn down at times when I/O is still possible, leading to potential NULL or invalid pointer dereferences. Fixes: edb0872f44ec ("block: move the bdi from the request_queue to the gendisk") Reported-by: syzbot <syzbot+aa0801b6b32dca9dda82@syzkaller.appspotmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Sven Schnelle <svens@linux.ibm.com> Link: https://lore.kernel.org/r/20210816134624.GA24234@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-09block: move the bdi from the request_queue to the gendiskChristoph Hellwig
The backing device information only makes sense for file system I/O, and thus belongs into the gendisk and not the lower level request_queue structure. Move it there. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20210809141744.1203023-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-21blk-wbt: make sure throttle is enabled properlyZhang Yi
After commit a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt"), if throttle was disabled by wbt_disable_default(), we could not enable again, fix this by set enable_state back to WBT_STATE_ON_DEFAULT. Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt") Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://lore.kernel.org/r/20210619093700.920393-3-yi.zhang@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>