kernel/git/next/linux-next.git/drivers/md/dm-bufio.c, branch master

dm-bufio: fix wrong count calculation in dm_bufio_issue_discard

2026-07-10T16:39:17+00:00

block_to_sector converts a block number to a sector number and adds c->start to the result. It is inappropriate to use this function for converting the number of blocks to a number to sectors because c->start would be incorrectly added to the result. Luckily, the only target that uses dm_bufio_issue_discard is dm-ebs, which sets c->start to 0, so this bug is latent. Signed-off-by: Mikulas Patocka Assisted-by: Claude:claude-opus-4-6 Fixes: 6fbeb0048e6b ("dm bufio: implement discard") Cc: stable@vger.kernel.org

dm-bufio: use kzalloc_flex

2026-03-26T17:31:15+00:00

Avoid manual size calculations and use the proper helper. Add __counted_by for extra runtime analysis. Signed-off-by: Rosen Penev Signed-off-by: Mikulas Patocka

dm-bufio: avoid redundant buffer_tree lookups

2026-01-19T14:39:21+00:00

dm-bufio's map from block number to buffer is organized as a hash table of red-black trees. It does far more lookups in this hash table than necessary: typically one lookup to lock the tree, one lookup to search the tree, and one lookup to unlock the tree. Only one of those lookups is needed. Optimize it to do only the minimum number of lookups. This improves performance. It also reduces the object code size, considering that the redundant hash table lookups were being inlined. For example, the size of the text section of dm-bufio.o decreases from 15599 to 15070 bytes with gcc 15 and x86_64, or from 20652 to 20244 bytes with clang 21 and arm64. Signed-off-by: Eric Biggers Signed-off-by: Mikulas Patocka

dm-bufio: merge cache_put() into cache_put_and_wake()

2026-01-19T14:38:28+00:00

Merge cache_put() into its only caller, cache_put_and_wake(). Signed-off-by: Eric Biggers Signed-off-by: Mikulas Patocka

dm: add WQ_PERCPU to alloc_workqueue users

2026-01-14T12:16:00+00:00

This continues the effort to refactor workqueue APIs, which began with the introduction of new workqueues and a new alloc_workqueue flag in: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The refactoring is going to alter the default behavior of alloc_workqueue() to be unbound by default. 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. For more details see the Link tag below. In order to keep alloc_workqueue() behavior identical, explicitly request WQ_PERCPU. Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/ Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Signed-off-by: Mikulas Patocka

dm-bufio: align write boundary on physical block size

2025-12-10T18:28:22+00:00

There may be devices with physical block size larger than 4k. If dm-bufio sends I/O that is not aligned on physical block size, performance is degraded. The 4k minimum alignment limit is there because some SSDs report logical and physical block size 512 despite having 4k internally - so dm-bufio shouldn't send I/Os not aligned on 4k boundary, because they perform badly (the SSD does read-modify-write for them). Signed-off-by: Mikulas Patocka Reported-by: Uladzislau Rezki (Sony) Cc: stable@vger.kernel.org

Merge tag 'for-6.18/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2025-10-04T01:48:02+00:00

Pull device mapper updates from Mikulas Patocka: - a new dm-pcache target for read/write caching on persistent memory - fix typos in docs - misc small refactoring - mark dm-error with DM_TARGET_PASSES_INTEGRITY - dm-request-based: fix NULL pointer dereference and quiesce_depth out of sync - dm-linear: optimize REQ_PREFLUSH - dm-vdo: return error on corrupted metadata - dm-integrity: support asynchronous hash interface * tag 'for-6.18/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (27 commits) dm raid: use proper md_ro_state enumerators dm-integrity: prefer synchronous hash interface dm-integrity: enable asynchronous hash interface dm-integrity: rename internal_hash dm-integrity: add the "offset" argument dm-integrity: allocate the recalculate buffer with kmalloc dm-integrity: introduce integrity_kmap and integrity_kunmap dm-integrity: replace bvec_kmap_local with kmap_local_page dm-integrity: use internal variable for digestsize dm vdo: return error on corrupted metadata in start_restoring_volume functions dm vdo: Update code to use mem_is_zero dm: optimize REQ_PREFLUSH with data when using the linear target dm-pcache: use int type to store negative error codes dm: fix "writen"->"written" dm-pcache: cleanup: fix coding style report by checkpatch.pl dm-pcache: remove ctrl_lock for pcache_cache_segment dm: fix NULL pointer dereference in __dm_suspend() dm: fix queue start/stop imbalance under suspend/load/resume races dm-pcache: add persistent cache target in device-mapper dm error: mark as DM_TARGET_PASSES_INTEGRITY ...

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

dm bufio: remove redundant __GFP_NOWARN

2025-08-19T09:12:50+00:00

GFP_NOWAIT already includes __GFP_NOWARN, so let's remove the redundant __GFP_NOWARN. Also update comments to clarify the flag semantics. Signed-off-by: Qianfeng Rong Signed-off-by: Mikulas Patocka

dm-bufio: fix sched in atomic context

2025-07-10T14:48:50+00:00

If "try_verify_in_tasklet" is set for dm-verity, DM_BUFIO_CLIENT_NO_SLEEP is enabled for dm-bufio. However, when bufio tries to evict buffers, there is a chance to trigger scheduling in spin_lock_bh, the following warning is hit: BUG: sleeping function called from invalid context at drivers/md/dm-bufio.c:2745 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 123, name: kworker/2:2 preempt_count: 201, expected: 0 RCU nest depth: 0, expected: 0 4 locks held by kworker/2:2/123: #0: ffff88800a2d1548 ((wq_completion)dm_bufio_cache){....}-{0:0}, at: process_one_work+0xe46/0x1970 #1: ffffc90000d97d20 ((work_completion)(&dm_bufio_replacement_work)){....}-{0:0}, at: process_one_work+0x763/0x1970 #2: ffffffff8555b528 (dm_bufio_clients_lock){....}-{3:3}, at: do_global_cleanup+0x1ce/0x710 #3: ffff88801d5820b8 (&c->spinlock){....}-{2:2}, at: do_global_cleanup+0x2a5/0x710 Preemption disabled at: [<0000000000000000>] 0x0 CPU: 2 UID: 0 PID: 123 Comm: kworker/2:2 Not tainted 6.16.0-rc3-g90548c634bd0 #305 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 Workqueue: dm_bufio_cache do_global_cleanup Call Trace: dump_stack_lvl+0x53/0x70 __might_resched+0x360/0x4e0 do_global_cleanup+0x2f5/0x710 process_one_work+0x7db/0x1970 worker_thread+0x518/0xea0 kthread+0x359/0x690 ret_from_fork+0xf3/0x1b0 ret_from_fork_asm+0x1a/0x30 That can be reproduced by: veritysetup format --data-block-size=4096 --hash-block-size=4096 /dev/vda /dev/vdb SIZE=$(blockdev --getsz /dev/vda) dmsetup create myverity -r --table "0 $SIZE verity 1 /dev/vda /dev/vdb 4096 4096 1 sha256 1 try_verify_in_tasklet" mount /dev/dm-0 /mnt -o ro echo 102400 > /sys/module/dm_bufio/parameters/max_cache_size_bytes [read files in /mnt] Cc: stable@vger.kernel.org # v6.4+ Fixes: 450e8dee51aa ("dm bufio: improve concurrent IO performance") Signed-off-by: Wang Shuai Signed-off-by: Sheng Yong Signed-off-by: Mikulas Patocka