kernel/linux.git/drivers/md/bcache, branch v6.19.11

bcache: fix I/O accounting leak in detached_dev_do_request

2026-01-29T02:06:55+00:00

When a bcache device is detached, discard requests are completed immediately. However, the I/O accounting started in cached_dev_make_request() is not ended, leading to 100% disk utilization reports in iostat. Add the missing bio_end_io_acct() call. Fixes: cafe56359144 ("bcache: A block layer cache") Signed-off-by: Shida Zhang Acked-by: Coly Li Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

bcache: remove dead code in detached_dev_do_request

2026-01-29T02:06:55+00:00

bio_alloc_clone() with GFP_NOIO and a mempool will not return NULL. Remove the unnecessary NULL check. Suggested-by: Christoph Hellwig Signed-off-by: Shida Zhang Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

bcache: use bio cloning for detached device requests

2026-01-22T14:24:50+00:00

Previously, bcache hijacked the bi_end_io and bi_private fields of the incoming bio when the backing device was in a detached state. This is fragile and breaks if the bio is needed to be processed by other layers. This patch transitions to using a cloned bio embedded within a private structure. This ensures the original bio's metadata remains untouched. Fixes: 53280e398471 ("bcache: fix improper use of bi_end_io") Co-developed-by: Christoph Hellwig Signed-off-by: Christoph Hellwig Signed-off-by: Shida Zhang Acked-by: Coly Li Signed-off-by: Jens Axboe

bcache: fix improper use of bi_end_io

2025-12-09T17:20:03+00:00

Don't call bio->bi_end_io() directly. Use the bio_endio() helper function instead, which handles completion more safely and uniformly. Suggested-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Signed-off-by: Shida Zhang Signed-off-by: Jens Axboe

bcache: Avoid -Wflex-array-member-not-at-end warning

2025-11-13T16:18:06+00:00

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are getting ready to enable it, globally. Use the new TRAILING_OVERLAP() helper to fix the following warning: drivers/md/bcache/bset.h:330:27: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] This helper creates a union between a flexible-array member (FAM) and a set of MEMBERS that would otherwise follow it. This overlays the trailing MEMBER struct btree_iter_set stack_data[MAX_BSETS]; onto the FAM struct btree_iter::data[], while keeping the FAM and the start of MEMBER aligned. The static_assert() ensures this alignment remains, and it's intentionally placed immediately after the corresponding structures --no blank line in between. Signed-off-by: Gustavo A. R. Silva Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: WQ_PERCPU added to alloc_workqueue users

2025-11-13T16:18:06+00:00

Currently if a user enqueue a work item using schedule_delayed_work() the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to schedule_work() that is using system_wq and queue_work(), that makes use again of WORK_CPU_UNBOUND. This lack of consistentcy cannot be addressed without refactoring the API. alloc_workqueue() treats all queues as per-CPU by default, while unbound workqueues must opt-in via WQ_UNBOUND. This default is suboptimal: most workloads benefit from unbound queues, allowing the scheduler to place worker threads where they’re needed and reducing noise when CPUs are isolated. This patch continues the effort to refactor worqueue APIs, which has begun with the change introducing new workqueues and a new alloc_workqueue flag: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") This change adds a new WQ_PERCPU flag to explicitly request alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND must now use WQ_PERCPU. Once migration is complete, WQ_UNBOUND can be removed and unbound will become the implicit default. Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: replace use of system_wq with system_percpu_wq

2025-11-13T16:18:06+00:00

Currently if a user enqueues a work item using schedule_delayed_work() the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to schedule_work() that is using system_wq and queue_work(), that makes use again of WORK_CPU_UNBOUND. This lack of consistency cannot be addressed without refactoring the API. This patch continues the effort to refactor worqueue APIs, which has begun with the change introducing new workqueues and a new alloc_workqueue flag: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") system_wq should be the per-cpu workqueue, yet in this name nothing makes that clear, so replace system_wq with system_percpu_wq. The old wq (system_wq) will be kept for a few release cycles. Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: remove redundant __GFP_NOWARN

2025-11-13T16:18:06+00:00

GFP_NOWAIT already includes __GFP_NOWARN, so let's remove the redundant __GFP_NOWARN. Signed-off-by: Qianfeng Rong Acked-by: Coly Li Acked-by: Coly Li Signed-off-by: Jens Axboe

bcache: reduce gc latency by processing less nodes and sleep less time

2025-11-13T16:18:06+00:00

When bcache device is busy for high I/O loads, there are two methods to reduce the garbage collection latency, - Process less nodes in eac loop of incremental garbage collection in btree_gc_recurse(). - Sleep less time between two full garbage collection in bch_btree_gc(). This patch introduces to hleper routines to provide different garbage collection nodes number and sleep intervel time. - btree_gc_min_nodes() If there is no front end I/O, return 128 nodes to process in each incremental loop, otherwise only 10 nodes are returned. Then front I/O is able to access the btree earlier. - btree_gc_sleep_ms() If there is no synchronized wait for bucket allocation, sleep 100 ms between two incremental GC loop. Othersize only sleep 10 ms before incremental GC loop. Then a faster GC may provide available buckets earlier, to avoid most of bcache working threads from being starved by buckets allocation. The idea is inspired by works from Mingzhe Zou and Robert Pang, but much simpler and the expected behavior is more predictable. Signed-off-by: Coly Li Signed-off-by: Robert Pang Signed-off-by: Mingzhe Zou Signed-off-by: Jens Axboe

bcache: drop discard sysfs interface

2025-11-13T16:18:06+00:00

Since discard code is removed, now the sysfs interface to enable discard is useless. This patch removes the corresponding sysfs entry, and remove bool variable 'discard' from struct cache as well. Signed-off-by: Coly Li Signed-off-by: Jens Axboe