kernel/linux.git/drivers/md/bcache, branch v6.18.21

bcache: fix I/O accounting leak in detached_dev_do_request

2026-02-06T15:57:36+00:00

[ Upstream commit 4da7c5c3ec34d839bba6e035c3d05c447a2f9d4f ] 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 Signed-off-by: Sasha Levin

bcache: use bio cloning for detached device requests

2026-02-06T15:57:36+00:00

[ Upstream commit 3ef825dfd4e487d6f92b23ee2df2455814583ef4 ] 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 Stable-dep-of: 4da7c5c3ec34 ("bcache: fix I/O accounting leak in detached_dev_do_request") Signed-off-by: Sasha Levin

bcache: fix improper use of bi_end_io

2026-02-06T15:57:36+00:00

[ Upstream commit 53280e398471f0bddbb17b798a63d41264651325 ] 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 Stable-dep-of: 4da7c5c3ec34 ("bcache: fix I/O accounting leak in detached_dev_do_request") Signed-off-by: Sasha Levin

block: remove the bi_inline_vecs variable sized array from struct bio

2025-09-09T13:31:59+00:00

Bios are embedded into other structures, and at least spare is unhappy about embedding structures with variable sized arrays. There's no real need to the array anyway, we can replace it with a helper pointing to the memory just behind the bio, and with the previous cleanups there is very few site doing anything special with it. Signed-off-by: Christoph Hellwig Reviewed-by: John Garry Signed-off-by: Jens Axboe

block: add a bio_init_inline helper

2025-09-09T13:31:59+00:00

Just a simpler wrapper around bio_init for callers that want to initialize a bio with inline bvecs. Signed-off-by: Christoph Hellwig Reviewed-by: John Garry Reviewed-by: Yu Kuai Signed-off-by: Jens Axboe

bcache: switch from pages to folios in read_super()

2025-07-03T00:56:42+00:00

Retrieve a folio from the page cache instead of a page. Removes a hidden call to compound_head(). Then be sure to call folio_put() instead of put_page() to release it. That doesn't save any calls to compound_head(), just moves them around. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Coly Li Acked-back: Coly Li Link: https://lore.kernel.org/r/20250702024848.343370-1-colyli@kernel.org [axboe: commit message massaging] Signed-off-by: Jens Axboe

bcache: remove unnecessary select MIN_HEAP

2025-06-20T03:48:03+00:00

After reverting the transition to the generic min heap library, bcache no longer depends on MIN_HEAP. The select entry can be removed to reduce code size and shrink the kernel's attack surface. This change effectively reverts the bcache-related part of commit 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions"). This is part of a series of changes to address a performance regression caused by the use of the generic min_heap implementation. As reported by Robert, bcache now suffers from latency spikes, with P100 (max) latency increasing from 600 ms to 2.4 seconds every 5 minutes. These regressions degrade bcache's effectiveness as a low-latency cache layer and lead to frequent timeouts and application stalls in production environments. Link: https://lore.kernel.org/lkml/CAJhEC05+0S69z+3+FB2Cd0hD+pCRyWTKLEOsc8BOmH73p1m+KQ@mail.gmail.com Link: https://lkml.kernel.org/r/20250614202353.1632957-4-visitorckw@gmail.com Fixes: 866898efbb25 ("bcache: remove heap-related macros and switch to generic min_heap") Fixes: 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions") Signed-off-by: Kuan-Wei Chiu Reported-by: Robert Pang Closes: https://lore.kernel.org/linux-bcache/CAJhEC06F_AtrPgw2-7CvCqZgeStgCtitbD-ryuPpXQA-JG5XXw@mail.gmail.com Acked-by: Coly Li Cc: Ching-Chun (Jim) Huang Cc: Kent Overstreet Cc: Signed-off-by: Andrew Morton

Revert "bcache: remove heap-related macros and switch to generic min_heap"

2025-06-20T03:48:03+00:00

This reverts commit 866898efbb25bb44fd42848318e46db9e785973a. The generic bottom-up min_heap implementation causes performance regression in invalidate_buckets_lru(), a hot path in bcache. Before the cache is fully populated, new_bucket_prio() often returns zero, leading to many equal comparisons. In such cases, bottom-up sift_down performs up to 2 * log2(n) comparisons, while the original top-down approach completes with just O() comparisons, resulting in a measurable performance gap. The performance degradation is further worsened by the non-inlined min_heap API functions introduced in commit 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions"), adding function call overhead to this critical path. As reported by Robert, bcache now suffers from latency spikes, with P100 (max) latency increasing from 600 ms to 2.4 seconds every 5 minutes. These regressions degrade bcache's effectiveness as a low-latency cache layer and lead to frequent timeouts and application stalls in production environments. This revert aims to restore bcache's original low-latency behavior. Link: https://lore.kernel.org/lkml/CAJhEC05+0S69z+3+FB2Cd0hD+pCRyWTKLEOsc8BOmH73p1m+KQ@mail.gmail.com Link: https://lkml.kernel.org/r/20250614202353.1632957-3-visitorckw@gmail.com Fixes: 866898efbb25 ("bcache: remove heap-related macros and switch to generic min_heap") Fixes: 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions") Signed-off-by: Kuan-Wei Chiu Reported-by: Robert Pang Closes: https://lore.kernel.org/linux-bcache/CAJhEC06F_AtrPgw2-7CvCqZgeStgCtitbD-ryuPpXQA-JG5XXw@mail.gmail.com Acked-by: Coly Li Cc: Ching-Chun (Jim) Huang Cc: Kent Overstreet Cc: Signed-off-by: Andrew Morton

Revert "bcache: update min_heap_callbacks to use default builtin swap"

2025-06-20T03:48:02+00:00

Patch series "bcache: Revert min_heap migration due to performance regression". This patch series reverts the migration of bcache from its original heap implementation to the generic min_heap library. While the original change aimed to simplify the code and improve maintainability, it introduced a severe performance regression in real-world scenarios. As reported by Robert, systems using bcache now suffer from periodic latency spikes, with P100 (max) latency increasing from 600 ms to 2.4 seconds every 5 minutes. This degrades bcache's value as a low-latency caching layer, and leads to frequent timeouts and application stalls in production environments. The primary cause of this regression is the behavior of the generic min_heap implementation's bottom-up sift_down, which performs up to 2 * log2(n) comparisons when many elements are equal. The original top-down variant used by bcache only required O(1) comparisons in such cases. The issue was further exacerbated by commit 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions"), which introduced non-inlined versions of the min_heap API, adding function call overhead to a performance-critical hot path. This patch (of 3): This reverts commit 3d8a9a1c35227c3f1b0bd132c9f0a80dbda07b65. Although removing the custom swap function simplified the code, this change is part of a broader migration to the generic min_heap API that introduced significant performance regressions in bcache. As reported by Robert, bcache now suffers from latency spikes, with P100 (max) latency increasing from 600 ms to 2.4 seconds every 5 minutes. These regressions degrade bcache's effectiveness as a low-latency cache layer and lead to frequent timeouts and application stalls in production environments. This revert is part of a series of changes to restore previous performance by undoing the min_heap transition. Link: https://lkml.kernel.org/r/20250614202353.1632957-1-visitorckw@gmail.com Link: https://lore.kernel.org/lkml/CAJhEC05+0S69z+3+FB2Cd0hD+pCRyWTKLEOsc8BOmH73p1m+KQ@mail.gmail.com Link: https://lkml.kernel.org/r/20250614202353.1632957-2-visitorckw@gmail.com Fixes: 866898efbb25 ("bcache: remove heap-related macros and switch to generic min_heap") Fixes: 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions") Signed-off-by: Kuan-Wei Chiu Reported-by: Robert Pang Closes: https://lore.kernel.org/linux-bcache/CAJhEC06F_AtrPgw2-7CvCqZgeStgCtitbD-ryuPpXQA-JG5XXw@mail.gmail.com Acked-by: Coly Li Cc: Ching-Chun (Jim) Huang Cc: Kent Overstreet Cc: Signed-off-by: Andrew Morton

treewide, timers: Rename from_timer() to timer_container_of()

2025-06-08T07:07:37+00:00

Move this API to the canonical timer_*() namespace. [ tglx: Redone against pre rc1 ] Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com