kernel/linux.git/drivers/md/dm-bufio.c, branch v6.12.80

dm-bufio: align write boundary on physical block size

2026-01-08T09:14:44+00:00

commit d0ac06ae53be0cdb61f5fe6b62d25d3317c51657 upstream. 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 Signed-off-by: Greg Kroah-Hartman

dm-bufio: fix sched in atomic context

2025-07-24T06:56:22+00:00

commit b1bf1a782fdf5c482215c0c661b5da98b8e75773 upstream. 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 Signed-off-by: Greg Kroah-Hartman

dm-bufio: don't schedule in atomic context

2025-05-09T07:50:33+00:00

commit a3d8f0a7f5e8b193db509c7191fefeed3533fc44 upstream. A BUG was reported as below when CONFIG_DEBUG_ATOMIC_SLEEP and try_verify_in_tasklet are enabled. [ 129.444685][ T934] BUG: sleeping function called from invalid context at drivers/md/dm-bufio.c:2421 [ 129.444723][ T934] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 934, name: kworker/1:4 [ 129.444740][ T934] preempt_count: 201, expected: 0 [ 129.444756][ T934] RCU nest depth: 0, expected: 0 [ 129.444781][ T934] Preemption disabled at: [ 129.444789][ T934] [] shrink_work+0x21c/0x248 [ 129.445167][ T934] kernel BUG at kernel/sched/walt/walt_debug.c:16! [ 129.445183][ T934] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP [ 129.445204][ T934] Skip md ftrace buffer dump for: 0x1609e0 [ 129.447348][ T934] CPU: 1 PID: 934 Comm: kworker/1:4 Tainted: G W OE 6.6.56-android15-8-o-g6f82312b30b9-debug #1 1400000003000000474e5500b3187743670464e8 [ 129.447362][ T934] Hardware name: Qualcomm Technologies, Inc. Parrot QRD, Alpha-M (DT) [ 129.447373][ T934] Workqueue: dm_bufio_cache shrink_work [ 129.447394][ T934] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 129.447406][ T934] pc : android_rvh_schedule_bug+0x0/0x8 [sched_walt_debug] [ 129.447435][ T934] lr : __traceiter_android_rvh_schedule_bug+0x44/0x6c [ 129.447451][ T934] sp : ffffffc0843dbc90 [ 129.447459][ T934] x29: ffffffc0843dbc90 x28: ffffffffffffffff x27: 0000000000000c8b [ 129.447479][ T934] x26: 0000000000000040 x25: ffffff804b3d6260 x24: ffffffd816232b68 [ 129.447497][ T934] x23: ffffff805171c5b4 x22: 0000000000000000 x21: ffffffd816231900 [ 129.447517][ T934] x20: ffffff80306ba898 x19: 0000000000000000 x18: ffffffc084159030 [ 129.447535][ T934] x17: 00000000d2b5dd1f x16: 00000000d2b5dd1f x15: ffffffd816720358 [ 129.447554][ T934] x14: 0000000000000004 x13: ffffff89ef978000 x12: 0000000000000003 [ 129.447572][ T934] x11: ffffffd817a823c4 x10: 0000000000000202 x9 : 7e779c5735de9400 [ 129.447591][ T934] x8 : ffffffd81560d004 x7 : 205b5d3938373434 x6 : ffffffd8167397c8 [ 129.447610][ T934] x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffffffc0843db9e0 [ 129.447629][ T934] x2 : 0000000000002f15 x1 : 0000000000000000 x0 : 0000000000000000 [ 129.447647][ T934] Call trace: [ 129.447655][ T934] android_rvh_schedule_bug+0x0/0x8 [sched_walt_debug 1400000003000000474e550080cce8a8a78606b6] [ 129.447681][ T934] __might_resched+0x190/0x1a8 [ 129.447694][ T934] shrink_work+0x180/0x248 [ 129.447706][ T934] process_one_work+0x260/0x624 [ 129.447718][ T934] worker_thread+0x28c/0x454 [ 129.447729][ T934] kthread+0x118/0x158 [ 129.447742][ T934] ret_from_fork+0x10/0x20 [ 129.447761][ T934] Code: ???????? ???????? ???????? d2b5dd1f (d4210000) [ 129.447772][ T934] ---[ end trace 0000000000000000 ]--- dm_bufio_lock will call spin_lock_bh when try_verify_in_tasklet is enabled, and __scan will be called in atomic context. Fixes: 7cd326747f46 ("dm bufio: remove dm_bufio_cond_resched()") Signed-off-by: LongPing Wei Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Signed-off-by: Greg Kroah-Hartman

dm-bufio: fix warnings about duplicate slab caches

2024-11-11T16:04:18+00:00

The commit 4c39529663b9 adds a warning about duplicate cache names if CONFIG_DEBUG_VM is selected. These warnings are triggered by the dm-bufio code. The dm-bufio code allocates a slab cache with each client. It is not possible to preallocate the caches in the module init function because the size of auxiliary per-buffer data is not known at this point. So, this commit changes dm-bufio so that it appends a unique atomic value to the cache name, to avoid the warnings. Signed-off-by: Mikulas Patocka Fixes: 4c39529663b9 ("slab: Warn on duplicate cache names when DEBUG_VM=y")

dm bufio: Remove NULL check of list_entry()

2024-08-22T16:32:55+00:00

list_entry() will never return a NULL pointer, thus remove the check. Signed-off-by: Yuesong Li Signed-off-by: Mikulas Patocka

dm: update relevant MODULE_AUTHOR entries to latest dm-devel mailing list

2024-02-20T19:22:55+00:00

Signed-off-by: Mike Snitzer

dm bufio: Support IO priority

2024-02-20T19:22:55+00:00

Some IO will dispatch from kworker with different io_context settings than the submitting task, we may need to specify a priority to avoid losing priority. Add dm_bufio_read_with_ioprio() and dm_bufio_prefetch_with_ioprio() for use by bufio users to pass an ioprio other than IOPRIO_DEFAULT. Co-developed-by: Yibin Ding Signed-off-by: Yibin Ding Signed-off-by: Hongyu Jin Reviewed-by: Eric Biggers Reviewed-by: Mikulas Patocka [snitzer: introduced _with_ioprio() wrappers to reduce churn] Signed-off-by: Mike Snitzer

dm io: Support IO priority

2024-02-20T19:22:51+00:00

Some IO will dispatch from kworker with different io_context settings than the submitting task, we may need to specify a priority to avoid losing priority. Add IO priority parameter to dm_io() and update all callers. Co-developed-by: Yibin Ding Signed-off-by: Yibin Ding Signed-off-by: Hongyu Jin Reviewed-by: Eric Biggers Reviewed-by: Mikulas Patocka Signed-off-by: Mike Snitzer

mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER

2024-01-08T23:27:15+00:00

commit 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely") has changed the definition of MAX_ORDER to be inclusive. This has caused issues with code that was not yet upstream and depended on the previous definition. To draw attention to the altered meaning of the define, rename MAX_ORDER to MAX_PAGE_ORDER. Link: https://lkml.kernel.org/r/20231228144704.14033-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Cc: Linus Torvalds Signed-off-by: Andrew Morton

dm-bufio: fix no-sleep mode

2023-11-17T19:41:14+00:00

dm-bufio has a no-sleep mode. When activated (with the DM_BUFIO_CLIENT_NO_SLEEP flag), the bufio client is read-only and we could call dm_bufio_get from tasklets. This is used by dm-verity. Unfortunately, commit 450e8dee51aa ("dm bufio: improve concurrent IO performance") broke this and the kernel would warn that cache_get() was calling down_read() from no-sleeping context. The bug can be reproduced by using "veritysetup open" with the "--use-tasklets" flag. This commit fixes dm-bufio, so that the tasklet mode works again, by expanding use of the 'no_sleep_enabled' static_key to conditionally use either a rw_semaphore or rwlock_t (which are colocated in the buffer_tree structure using a union). Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org # v6.4 Fixes: 450e8dee51aa ("dm bufio: improve concurrent IO performance") Signed-off-by: Mike Snitzer