Commit Graph

166 Commits

Author SHA1 Message Date
Sheng Yong
b1bf1a782f dm-bufio: fix sched in atomic context
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:
 <TASK>
 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
 </TASK>

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 <data_blocks> 1 sha256 <root_hash> <salt> 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: 450e8dee51 ("dm bufio: improve concurrent IO performance")
Signed-off-by: Wang Shuai <wangshuai12@xiaomi.com>
Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-07-10 16:48:50 +02:00
Linus Torvalds
3c727285f1 - dm: better error handling when reloading a table
- dm-delay: don't busy-wait in kthread
 
 - dm: use use generic disable_* functions instead of open coding them
 
 - dm: lock queue limits when reading them
 
 - dm-verity: use softirq context only when !need_resched()
 
 - dm-bufio: remove maximum age based eviction
 
 - dm: remove unneeded kvfree from alloc_targets
 
 - dm-flakey: various fixes
 
 - dm-mpath: interface for explicit probing of active paths
 
 - dm: fix BLK_FEAT_ATOMIC_WRITES
 
 - dm: pass through operations on wrapped inline crypto keys
 
 - dm vdo indexer: don't read request structure after enqueuing
 
 - dm-zone: Use bdev_*() helper functions where applicable
 
 - dm-mpath: replace spin_lock_irqsave with spin_lock_irq
 
 - dm-mirror: fix a tiny race condition
 
 - dm-verity: fix a memory leak if some arguments are specified multiple times
 
 - dm-stripe: small code cleanup
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Merge tag 'for-6.16/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mikulas Patocka:

 - better error handling when reloading a table

 - use use generic disable_* functions instead of open coding them

 - lock queue limits when reading them

 - remove unneeded kvfree from alloc_targets

 - fix BLK_FEAT_ATOMIC_WRITES

 - pass through operations on wrapped inline crypto keys

 - dm-verity:
     - use softirq context only when !need_resched()
     - fix a memory leak if some arguments are specified multiple times

 - dm-mpath:
    - interface for explicit probing of active paths
    - replace spin_lock_irqsave with spin_lock_irq

 - dm-delay: don't busy-wait in kthread

 - dm-bufio: remove maximum age based eviction

 - dm-flakey: various fixes

 - vdo indexer: don't read request structure after enqueuing

 - dm-zone: Use bdev_*() helper functions where applicable

 - dm-mirror: fix a tiny race condition

 - dm-stripe: small code cleanup

* tag 'for-6.16/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (29 commits)
  dm-stripe: small code cleanup
  dm-verity: fix a memory leak if some arguments are specified multiple times
  dm-mirror: fix a tiny race condition
  dm-table: check BLK_FEAT_ATOMIC_WRITES inside limits_lock
  dm mpath: replace spin_lock_irqsave with spin_lock_irq
  dm-mpath: Don't grab work_mutex while probing paths
  dm-zone: Use bdev_*() helper functions where applicable
  dm vdo indexer: don't read request structure after enqueuing
  dm: pass through operations on wrapped inline crypto keys
  blk-crypto: export wrapped key functions
  dm-table: Set BLK_FEAT_ATOMIC_WRITES for target queue limits
  dm mpath: Interface for explicit probing of active paths
  dm: Allow .prepare_ioctl to handle ioctls directly
  dm-flakey: make corrupting read bios work
  dm-flakey: remove useless ERROR_READS check in flakey_end_io
  dm-flakey: error all IOs when num_features is absent
  dm-flakey: Clean up parsing messages
  dm: remove unneeded kvfree from alloc_targets
  dm-bufio: remove maximum age based eviction
  dm-verity: use softirq context only when !need_resched()
  ...
2025-06-03 15:54:46 -07:00
Linus Torvalds
6f59de9bc0 for-6.16/block-20250523
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Merge tag 'for-6.16/block-20250523' of git://git.kernel.dk/linux

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
  ...
2025-05-26 11:39:36 -07:00
Christoph Hellwig
9134124ce1 dm-bufio: use bio_add_virt_nofail
Convert the __bio_add_page(..., virt_to_page(), ...) pattern to the
bio_add_virt_nofail helper implementing it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250507120451.4000627-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-07 07:31:07 -06:00
Eric Biggers
9769378133 dm-bufio: remove maximum age based eviction
Every 30 seconds, dm-bufio evicts all buffers that were not accessed
within the last max_age_seconds, except those pinned in memory via
retain_bytes.  By default max_age_seconds is 300 (i.e. 5 minutes), and
retain_bytes is 262144 (i.e. 256 KiB) per dm-bufio client.

This eviction algorithm is much too eager and is also redundant with the
shinker based eviction.

Testing on an Android phone shows that about 30 MB of dm-bufio buffers
(from dm-verity Merkle tree blocks) are loaded at boot time, and then
about 90% of them are suddenly thrown away 5 minutes after boot.  This
results in unnecessary Merkle tree I/O later.

Meanwhile, if the system actually encounters memory pressure, testing
also shows that the shrinker is effective at evicting the buffers.

Other major Linux kernel caches, such as the page cache, do not enforce
a maximum age, instead relying on the shrinker.

For these reasons, Android is now setting max_age_seconds to 86400
(i.e. 1 day), which mostly disables it; see
cadad290a7%5E%21/

That is a much better default, but really the maximum age based eviction
should not exist at all.  Let's remove it.

Note that this also eliminates the need to run work every 30 seconds,
which is beneficial too.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-05-04 11:35:05 +02:00
LongPing Wei
a3d8f0a7f5 dm-bufio: don't schedule in atomic context
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] [<ffffffd816231900>] 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: 7cd326747f ("dm bufio: remove dm_bufio_cond_resched()")
Signed-off-by: LongPing Wei <weilongping@oppo.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-04-23 13:09:10 +02:00
Mikulas Patocka
3be1f25393 dm-bufio: remove unused return value
The return value of the function "forget_buffer" is not tested, so we can
remove it.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-02-24 11:42:23 +01:00
Mikulas Patocka
61a57254a9 dm-bufio: use kmalloc to allocate power-of-two sized buffers
Vlastimil Babka said [1] that kmalloc will return a power-of-two-aligned
buffer if it was called with a power-of-two size. So, we can use kmalloc
instead of our own slab cache in dm-bufio. Note that the code for the
slab cache was not removed because dm-bufio supports non-power-of-two
buffer sizes.

Link: https://lore.kernel.org/linux-mm/e7fca292-7c79-4f97-a90c-d68178d8ca59@suse.cz/ [1]

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-11-20 11:44:23 +01:00
Mikulas Patocka
42964e4b5e dm-bufio: fix warnings about duplicate slab caches
The commit 4c39529663 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 <mpatocka@redhat.com>
Fixes: 4c39529663 ("slab: Warn on duplicate cache names when DEBUG_VM=y")
2024-11-11 17:04:18 +01:00
Yuesong Li
02c0207ecd dm bufio: Remove NULL check of list_entry()
list_entry() will never return a NULL pointer, thus remove the
check.

Signed-off-by: Yuesong Li <liyuesong@vivo.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-08-22 18:32:55 +02:00
Mike Snitzer
fa34e5893f dm: update relevant MODULE_AUTHOR entries to latest dm-devel mailing list
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2024-02-20 14:22:55 -05:00
Hongyu Jin
e9b2238e47 dm bufio: Support IO priority
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 <yibin.ding@unisoc.com>
Signed-off-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Hongyu Jin <hongyu.jin@unisoc.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
[snitzer: introduced _with_ioprio() wrappers to reduce churn]
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2024-02-20 14:22:55 -05:00
Hongyu Jin
6e5f0f6383 dm io: Support IO priority
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 <yibin.ding@unisoc.com>
Signed-off-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Hongyu Jin <hongyu.jin@unisoc.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2024-02-20 14:22:51 -05:00
Kirill A. Shutemov
5e0a760b44 mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER
commit 23baf831a3 ("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 <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-01-08 15:27:15 -08:00
Mikulas Patocka
2a695062a5 dm-bufio: fix no-sleep mode
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 450e8dee51 ("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 <mpatocka@redhat.com>
Cc: stable@vger.kernel.org	# v6.4
Fixes: 450e8dee51 ("dm bufio: improve concurrent IO performance")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-11-17 14:41:14 -05:00
Qi Zheng
1f1d459c9a dm: dynamically allocate the dm-bufio shrinker
In preparation for implementing lockless slab shrink, use new APIs to
dynamically allocate the dm-bufio shrinker, so that it can be freed
asynchronously via RCU. Then it doesn't need to wait for RCU read-side
critical section when releasing the struct dm_bufio_client.

Link: https://lkml.kernel.org/r/20230911094444.68966-24-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-04 10:32:25 -07:00
Mikulas Patocka
e2c789cab6 dm: get rid of GFP_NOIO workarounds for __vmalloc and kvmalloc
In the past, the function __vmalloc didn't respect the GFP flags - it
allocated memory with the provided gfp flags, but it allocated page tables
with GFP_KERNEL. This was fixed in commit 451769ebb7 ("mm/vmalloc:
alloc GFP_NO{FS,IO} for vmalloc") so the memalloc_noio_{save,restore}
workaround is no longer needed.

The function kvmalloc didn't like flags different from GFP_KERNEL. This
was fixed in commit a421ef3030 ("mm: allow !GFP_KERNEL allocations
for kvmalloc"), so kvmalloc can now be called with GFP_NOIO.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-06-27 16:06:54 -04:00
Li Lingfeng
d483001206 dm thin metadata: Fix ABBA deadlock by resetting dm_bufio_client
As described in commit 8111964f1b ("dm thin: Fix ABBA deadlock between
shrink_slab and dm_pool_abort_metadata"), ABBA deadlocks will be
triggered because shrinker_rwsem currently needs to held by
dm_pool_abort_metadata() as a side-effect of thin-pool metadata
operation failure.

The following three problem scenarios have been noticed:

1) Described by commit 8111964f1b ("dm thin: Fix ABBA deadlock between
   shrink_slab and dm_pool_abort_metadata")

2) shrinker_rwsem and throttle->lock
          P1(drop cache)                        P2(kworker)
drop_caches_sysctl_handler
 drop_slab
  shrink_slab
   down_read(&shrinker_rwsem)  - LOCK A
   do_shrink_slab
    super_cache_scan
     prune_icache_sb
      dispose_list
       evict
        ext4_evict_inode
         ext4_clear_inode
          ext4_discard_preallocations
           ext4_mb_load_buddy_gfp
            ext4_mb_init_cache
             ext4_wait_block_bitmap
              __ext4_error
               ext4_handle_error
                ext4_commit_super
                 ...
                 dm_submit_bio
                                     do_worker
                                      throttle_work_update
                                       down_write(&t->lock) -- LOCK B
                                      process_deferred_bios
                                       commit
                                        metadata_operation_failed
                                         dm_pool_abort_metadata
                                          dm_block_manager_create
                                           dm_bufio_client_create
                                            register_shrinker
                                             down_write(&shrinker_rwsem)
                                             -- LOCK A
                 thin_map
                  thin_bio_map
                   thin_defer_bio_with_throttle
                    throttle_lock
                     down_read(&t->lock)  - LOCK B

3) shrinker_rwsem and wait_on_buffer
          P1(drop cache)                            P2(kworker)
drop_caches_sysctl_handler
 drop_slab
  shrink_slab
   down_read(&shrinker_rwsem)  - LOCK A
   do_shrink_slab
   ...
    ext4_wait_block_bitmap
     __ext4_error
      ext4_handle_error
       jbd2_journal_abort
        jbd2_journal_update_sb_errno
         jbd2_write_superblock
          submit_bh
           // LOCK B
           // RELEASE B
                             do_worker
                              throttle_work_update
                               down_write(&t->lock) - LOCK B
                              process_deferred_bios
                               process_bio
                               commit
                                metadata_operation_failed
                                 dm_pool_abort_metadata
                                  dm_block_manager_create
                                   dm_bufio_client_create
                                    register_shrinker
                                     register_shrinker_prepared
                                      down_write(&shrinker_rwsem)  - LOCK A
                               bio_endio
      wait_on_buffer
       __wait_on_buffer

Fix these by resetting dm_bufio_client without holding shrinker_rwsem.

Fixes: 8111964f1b ("dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata")
Cc: stable@vger.kernel.org
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-06-16 18:24:13 -04:00
Linus Torvalds
7fa8a8ee94 - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
switching from a user process to a kernel thread.
 
 - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav.
 
 - zsmalloc performance improvements from Sergey Senozhatsky.
 
 - Yue Zhao has found and fixed some data race issues around the
   alteration of memcg userspace tunables.
 
 - VFS rationalizations from Christoph Hellwig:
 
   - removal of most of the callers of write_one_page().
 
   - make __filemap_get_folio()'s return value more useful
 
 - Luis Chamberlain has changed tmpfs so it no longer requires swap
   backing.  Use `mount -o noswap'.
 
 - Qi Zheng has made the slab shrinkers operate locklessly, providing
   some scalability benefits.
 
 - Keith Busch has improved dmapool's performance, making part of its
   operations O(1) rather than O(n).
 
 - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
   permitting userspace to wr-protect anon memory unpopulated ptes.
 
 - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather
   than exclusive, and has fixed a bunch of errors which were caused by its
   unintuitive meaning.
 
 - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
   which causes minor faults to install a write-protected pte.
 
 - Vlastimil Babka has done some maintenance work on vma_merge():
   cleanups to the kernel code and improvements to our userspace test
   harness.
 
 - Cleanups to do_fault_around() by Lorenzo Stoakes.
 
 - Mike Rapoport has moved a lot of initialization code out of various
   mm/ files and into mm/mm_init.c.
 
 - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
   DRM, but DRM doesn't use it any more.
 
 - Lorenzo has also coverted read_kcore() and vread() to use iterators
   and has thereby removed the use of bounce buffers in some cases.
 
 - Lorenzo has also contributed further cleanups of vma_merge().
 
 - Chaitanya Prakash provides some fixes to the mmap selftesting code.
 
 - Matthew Wilcox changes xfs and afs so they no longer take sleeping
   locks in ->map_page(), a step towards RCUification of pagefaults.
 
 - Suren Baghdasaryan has improved mmap_lock scalability by switching to
   per-VMA locking.
 
 - Frederic Weisbecker has reworked the percpu cache draining so that it
   no longer causes latency glitches on cpu isolated workloads.
 
 - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
   logic.
 
 - Liu Shixin has changed zswap's initialization so we no longer waste a
   chunk of memory if zswap is not being used.
 
 - Yosry Ahmed has improved the performance of memcg statistics flushing.
 
 - David Stevens has fixed several issues involving khugepaged,
   userfaultfd and shmem.
 
 - Christoph Hellwig has provided some cleanup work to zram's IO-related
   code paths.
 
 - David Hildenbrand has fixed up some issues in the selftest code's
   testing of our pte state changing.
 
 - Pankaj Raghav has made page_endio() unneeded and has removed it.
 
 - Peter Xu contributed some rationalizations of the userfaultfd
   selftests.
 
 - Yosry Ahmed has fixed an issue around memcg's page recalim accounting.
 
 - Chaitanya Prakash has fixed some arm-related issues in the
   selftests/mm code.
 
 - Longlong Xia has improved the way in which KSM handles hwpoisoned
   pages.
 
 - Peter Xu fixes a few issues with uffd-wp at fork() time.
 
 - Stefan Roesch has changed KSM so that it may now be used on a
   per-process and per-cgroup basis.
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Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
   switching from a user process to a kernel thread.

 - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
   Raghav.

 - zsmalloc performance improvements from Sergey Senozhatsky.

 - Yue Zhao has found and fixed some data race issues around the
   alteration of memcg userspace tunables.

 - VFS rationalizations from Christoph Hellwig:
     - removal of most of the callers of write_one_page()
     - make __filemap_get_folio()'s return value more useful

 - Luis Chamberlain has changed tmpfs so it no longer requires swap
   backing. Use `mount -o noswap'.

 - Qi Zheng has made the slab shrinkers operate locklessly, providing
   some scalability benefits.

 - Keith Busch has improved dmapool's performance, making part of its
   operations O(1) rather than O(n).

 - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
   permitting userspace to wr-protect anon memory unpopulated ptes.

 - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
   rather than exclusive, and has fixed a bunch of errors which were
   caused by its unintuitive meaning.

 - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
   which causes minor faults to install a write-protected pte.

 - Vlastimil Babka has done some maintenance work on vma_merge():
   cleanups to the kernel code and improvements to our userspace test
   harness.

 - Cleanups to do_fault_around() by Lorenzo Stoakes.

 - Mike Rapoport has moved a lot of initialization code out of various
   mm/ files and into mm/mm_init.c.

 - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
   DRM, but DRM doesn't use it any more.

 - Lorenzo has also coverted read_kcore() and vread() to use iterators
   and has thereby removed the use of bounce buffers in some cases.

 - Lorenzo has also contributed further cleanups of vma_merge().

 - Chaitanya Prakash provides some fixes to the mmap selftesting code.

 - Matthew Wilcox changes xfs and afs so they no longer take sleeping
   locks in ->map_page(), a step towards RCUification of pagefaults.

 - Suren Baghdasaryan has improved mmap_lock scalability by switching to
   per-VMA locking.

 - Frederic Weisbecker has reworked the percpu cache draining so that it
   no longer causes latency glitches on cpu isolated workloads.

 - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
   logic.

 - Liu Shixin has changed zswap's initialization so we no longer waste a
   chunk of memory if zswap is not being used.

 - Yosry Ahmed has improved the performance of memcg statistics
   flushing.

 - David Stevens has fixed several issues involving khugepaged,
   userfaultfd and shmem.

 - Christoph Hellwig has provided some cleanup work to zram's IO-related
   code paths.

 - David Hildenbrand has fixed up some issues in the selftest code's
   testing of our pte state changing.

 - Pankaj Raghav has made page_endio() unneeded and has removed it.

 - Peter Xu contributed some rationalizations of the userfaultfd
   selftests.

 - Yosry Ahmed has fixed an issue around memcg's page recalim
   accounting.

 - Chaitanya Prakash has fixed some arm-related issues in the
   selftests/mm code.

 - Longlong Xia has improved the way in which KSM handles hwpoisoned
   pages.

 - Peter Xu fixes a few issues with uffd-wp at fork() time.

 - Stefan Roesch has changed KSM so that it may now be used on a
   per-process and per-cgroup basis.

* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
  mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
  shmem: restrict noswap option to initial user namespace
  mm/khugepaged: fix conflicting mods to collapse_file()
  sparse: remove unnecessary 0 values from rc
  mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
  hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
  maple_tree: fix allocation in mas_sparse_area()
  mm: do not increment pgfault stats when page fault handler retries
  zsmalloc: allow only one active pool compaction context
  selftests/mm: add new selftests for KSM
  mm: add new KSM process and sysfs knobs
  mm: add new api to enable ksm per process
  mm: shrinkers: fix debugfs file permissions
  mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
  migrate_pages_batch: fix statistics for longterm pin retry
  userfaultfd: use helper function range_in_vma()
  lib/show_mem.c: use for_each_populated_zone() simplify code
  mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
  fs/buffer: convert create_page_buffers to folio_create_buffers
  fs/buffer: add folio_create_empty_buffers helper
  ...
2023-04-27 19:42:02 -07:00
Kirill A. Shutemov
23baf831a3 mm, treewide: redefine MAX_ORDER sanely
MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.

This definition is counter-intuitive and lead to number of bugs all over
the kernel.

Change the definition of MAX_ORDER to be inclusive: the range of orders
user can ask from buddy allocator is 0..MAX_ORDER now.

[kirill@shutemov.name: fix min() warning]
  Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box
[akpm@linux-foundation.org: fix another min_t warning]
[kirill@shutemov.name: fixups per Zi Yan]
  Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name
[akpm@linux-foundation.org: fix underlining in docs]
  Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/
Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>	[powerpc]
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-05 19:42:46 -07:00
Joe Thornber
363b7fd76c dm: improve hash_locks sizing and hash function
Both bufio and bio-prison-v1 use the identical model for splitting
their respective locks and rbtrees. Improve dm_num_hash_locks() to
distribute across more rbtrees to improve overall performance -- but
the maximum number of locks/rbtrees is still 64.

Also factor out a common hash function named dm_hash_locks_index(),
the magic numbers used were determined to be best using this program:
 https://gist.github.com/jthornber/e05c47daa7b500c56dc339269c5467fc

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:51 -04:00
Mike Snitzer
1e84c4b732 dm bufio: intelligently size dm_buffer_cache's buffer_trees
Size the dm_buffer_cache's number of buffer_tree structs using
dm_num_hash_locks().

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:51 -04:00
Mike Snitzer
36c18b8639 dm bufio: prepare to intelligently size dm_buffer_cache's buffer_trees
Add num_locks member to dm_buffer_cache struct and use it rather than
the NR_LOCKS magic value (64).

Next commit will size the dm_buffer_cache's buffer_trees according to
dm_num_hash_locks().

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:51 -04:00
Mikulas Patocka
56c5de4406 dm bufio: use multi-page bio vector
The kernel supports multi page bio vector entries, so we can use them
in dm-bufio as an optimization.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Mikulas Patocka
f5f9354120 dm bufio: use waitqueue_active in __free_buffer_wake
Save one spinlock by using waitqueue_active. We hold the bufio lock at
this place, so no one can add entries to the waitqueue at this point.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Mike Snitzer
530f683ddc dm bufio: move dm_bufio_client members to avoid spanning cachelines
Movement also consolidates holes in dm_bufio_client struct. But the
overall size of the struct isn't changed.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Joe Thornber
791188065b dm bufio: add lock_history optimization for cache iterators
Sometimes it is beneficial to repeatedly get and drop locks as part of
an iteration.  Introduce lock_history struct to help avoid redundant
drop and gets of the same lock.

Optimizes cache_iterate, cache_mark_many and cache_evict.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Joe Thornber
450e8dee51 dm bufio: improve concurrent IO performance
When multiple threads perform IO to a thin device, the underlying
dm_bufio object can become a bottleneck; slowing down access to btree
nodes that store the thin metadata. Prior to this commit, each bufio
instance had a single mutex that was taken for every bufio operation.

This commit concentrates on improving the common case where: a user of
dm_bufio wishes to access, but not modify, a buffer which is already
within the dm_bufio cache.

Implementation::

  The code has been refactored; pulling out an 'lru' abstraction and a
  'buffer cache' abstraction (see 2 previous commits). This commit
  updates higher level bufio code (that performs allocation of buffers,
  IO and eviction/cache sizing) to leverage both abstractions. It also
  deals with the delicate locking requirements of both abstractions to
  provide finer grained locking. The result is significantly better
  concurrent IO performance.

  Before this commit, bufio has a global lru list it used to evict the
  oldest, clean buffers from _all_ clients. With the new locking we
  don’t want different ways to access the same buffer, so instead
  do_global_cleanup() loops around the clients asking them to free
  buffers older than a certain time.

  This commit also converts many old BUG_ONs to WARN_ON_ONCE, see the
  lru_evict and cache_evict code in particular.  They will return
  ER_DONT_EVICT if a given buffer somehow meets the invariants that
  should _never_ happen. [Aside from revising this commit's header and
  fixing coding style and whitespace nits: this switching to
  WARN_ON_ONCE is Mike Snitzer's lone contribution to this commit]

Testing::

  Some of the low level functions have been unit tested using dm-unit:
    https://github.com/jthornber/dm-unit/blob/main/src/tests/bufio.rs

  Higher level concurrency and IO is tested via a test only target
  found here:
    https://github.com/jthornber/linux/blob/2023-03-24-thin-concurrency-9/drivers/md/dm-bufio-test.c

  The associated userland side of these tests is here:
    https://github.com/jthornber/dmtest-python/blob/main/src/dmtest/bufio/bufio_tests.py

  In addition the full dmtest suite of tests (dm-thin, dm-cache, etc)
  has been run (~450 tests).

Performance::

  Most bufio operations have unchanged performance. But if multiple
  threads are attempting to get buffers concurrently, and these
  buffers are already in the cache then there's a big speed up. Eg,
  one test has 16 'hotspot' threads simulating btree lookups while
  another thread dirties the whole device. In this case the hotspot
  threads acquire the buffers about 25 times faster.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Joe Thornber
2cd7a6d41f dm bufio: add dm_buffer_cache abstraction
The buffer cache is responsible for managing the holder count,
tracking clean/dirty state, and choosing buffers via predicates.
Higher level code is responsible for allocation of buffers, IO and
eviction/cache sizing.

The buffer cache has thread safe methods for acquiring a reference
to an existing buffer. All other methods in buffer cache are _not_
threadsafe, and only contain enough locking to guarantee the safe
methods.

Rather than a single mutex, sharded rw_semaphores are used to allow
concurrent threads to 'get' buffers. Each rw_semaphore protects its
own rbtree of buffer entries.

Code that uses this new dm_buffer_cache abstraction will be introduced
in a following commit.

This commit moves the dm_buffer struct in preparation for finer grained
dm_buffer changes, in the next commit, to be more easily seen. It also
introduces temporary dm_buffer struct members to allow compilation of
this intermediate commit (they will be elided in the next commit).

This commit will cause "defined but not used" compiler warnings that
will be resolved by the next commit.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Joe Thornber
be845babda dm bufio: add LRU abstraction
A CLOCK algorithm is used in this LRU abstraction.  This avoids
relinking list nodes, which would require a write lock protecting it.

None of the LRU methods are threadsafe; locking must be done at a
higher level.

Code that uses this new LRU will be introduced in the next 2 commits.

As such, this commit will cause "defined but not used" compiler warnings
that will be resolved by the next 2 commits.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Mike Snitzer
b75a80f4f5 dm bufio: don't bug for clear developer oversight
Reasonable to relax to WARN_ON because these are easily avoided but do
offer some assurance future coding mistakes won't occur (if changes
tested properly).

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Mike Snitzer
0511228752 dm bufio: never crash if dm_bufio_in_request()
All these instances are entirely avoidable given that they speak to
coding mistakes that result in inappropriate use. Proper testing during
development will catch any such coding bug so its best to relax all of
these from BUG_ON to WARN_ON_ONCE.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Mike Snitzer
555977dd68 dm bufio: use WARN_ON in dm_bufio_client_destroy and dm_bufio_exit
Using BUG_ON when tearing down is excessive. Relax these to WARN_ONs.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Joe Thornber
96a2ff2a63 dm bufio: remove unused dm_bufio_release_move interface
Was used by multi-snapshot DM target that never went upstream.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-03-30 15:57:50 -04:00
Heinz Mauelshagen
8d1058fb2a dm: fix use of sizeof() macro
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:07 -05:00
Heinz Mauelshagen
6a80803472 dm: avoid using symbolic permissions
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:07 -05:00
Heinz Mauelshagen
0ef0b4717a dm: add missing empty lines
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Heinz Mauelshagen
02f10ba178 dm: add argument identifier names
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Heinz Mauelshagen
a4a82ce3d2 dm: correct block comments format.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Heinz Mauelshagen
2f06cd12e1 dm: avoid initializing static variables
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Heinz Mauelshagen
86a3238c7b dm: change "unsigned" to "unsigned int"
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Heinz Mauelshagen
3bd9400307 dm: add missing SPDX-License-Indentifiers
'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has
deprecated its use.

Suggested-by: John Wiele <jwiele@redhat.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2023-02-14 14:23:06 -05:00
Mike Snitzer
c87791bcc4 dm: improve shrinker debug names
Commit e33c267ab7 ("mm: shrinkers: provide shrinkers with names")
chose some fairly bad names for DM's shrinkers.

Fixes: e33c267ab7 ("mm: shrinkers: provide shrinkers with names")
Signed-off-by : Mike Snitzer <snitzer@kernel.org>
2023-01-30 14:20:04 -05:00
Zhihao Cheng
0dfc1f4cea dm bufio: Fix missing decrement of no_sleep_enabled if dm_bufio_client_create failed
The 'no_sleep_enabled' should be decreased in error handling path
in dm_bufio_client_create() when the DM_BUFIO_CLIENT_NO_SLEEP flag
is set, otherwise static_branch_unlikely() will always return true
even if no dm_bufio_client instances have DM_BUFIO_CLIENT_NO_SLEEP
flag set.

Cc: stable@vger.kernel.org
Fixes: 3c1c875d05 ("dm bufio: conditionally enable branching for DM_BUFIO_CLIENT_NO_SLEEP")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-11-18 10:23:55 -05:00
Mikulas Patocka
141b3523e9 dm bufio: use the acquire memory barrier when testing for B_READING
The function test_bit doesn't provide any memory barrier. It may be
possible that the read requests that follow test_bit(B_READING, &b->state)
are reordered before the test, reading invalid data that existed before
B_READING was cleared.

Fix this bug by changing test_bit to test_bit_acquire. This is
particularly important on arches with weak(er) memory ordering
(e.g. arm64).

Depends-On: 8238b45798 ("wait_on_bit: add an acquire memory barrier")
Depends-On: d6ffe6067a ("provide arch_test_bit_acquire for architectures that define test_bit")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-10-18 12:38:16 -04:00
Linus Torvalds
c3adefb5ba - A few fixes for the DM verity and bufio changes from the 6.0 merge.
- A smatch warning fix for DM writecache locking in writecache_map.
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Merge tag 'for-6.0/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - A few fixes for the DM verity and bufio changes in this merge window

 - A smatch warning fix for DM writecache locking in writecache_map

* tag 'for-6.0/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm bufio: fix some cases where the code sleeps with spinlock held
  dm writecache: fix smatch warning about invalid return from writecache_map
  dm verity: fix verity_parse_opt_args parsing
  dm verity: fix DM_VERITY_OPTS_MAX value yet again
  dm bufio: simplify DM_BUFIO_CLIENT_NO_SLEEP locking
2022-08-11 19:46:48 -07:00
Mikulas Patocka
e3a7c2947b dm bufio: fix some cases where the code sleeps with spinlock held
Commit b32d45824a ("dm bufio: Add DM_BUFIO_CLIENT_NO_SLEEP flag")
added a "NO_SLEEP" mode, it replaces a mutex with a spinlock, and it
is only usable when the device is in read-only mode (because the write
path may be sleeping while holding the dm_bufio_client lock).

However, there are still two points where the code could sleep even in
read-only mode. One is in __get_unclaimed_buffer -> __make_buffer_clean.
The other is in __try_evict_buffer -> __make_buffer_clean. These functions
will call __make_buffer_clean which sleeps if the buffer is being read.

Fix these cases so that if c->no_sleep is set __make_buffer_clean
will not be called and the buffer will be skipped instead.

Fixes: b32d45824a ("dm bufio: Add DM_BUFIO_CLIENT_NO_SLEEP flag")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-08-11 11:10:42 -04:00
Mike Snitzer
b33b6fdca3 dm bufio: simplify DM_BUFIO_CLIENT_NO_SLEEP locking
Historically none of the bufio code runs in interrupt context but with
the use of DM_BUFIO_CLIENT_NO_SLEEP a bufio client can, see: commit
5721d4e5a9 ("dm verity: Add optional "try_verify_in_tasklet" feature")
That said, the new tasklet usecase still doesn't require interrupts be
disabled by bufio (let alone conditionally restore them).

Yet with PREEMPT_RT, and falling back from tasklet to workqueue, care
must be taken to properly synchronize between softirq and process
context, otherwise ABBA deadlock may occur. While it is unnecessary to
disable bottom-half preemption within a tasklet, we must consistently do
so in process context to ensure locking is in the proper order.

Fix these issues by switching from spin_lock_irq{save,restore} to using
spin_{lock,unlock}_bh instead. Also remove the 'spinlock_flags' member
in dm_bufio_client struct (that can be used unsafely if bufio must
recurse on behalf of some caller, e.g. block layer's submit_bio).

Fixes: 5721d4e5a9 ("dm verity: Add optional "try_verify_in_tasklet" feature")
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2022-08-09 19:12:14 -04:00
Linus Torvalds
20cf903a0c - Add flags argument to dm_bufio_client_create and introduce
DM_BUFIO_CLIENT_NO_SLEEP flag to have dm-bufio use spinlock rather
   than mutex for its locking.
 
 - Add optional "try_verify_in_tasklet" feature to DM verity target.
   This feature gives users the option to improve IO latency by using a
   tasklet to verify, using hashes in bufio's cache, rather than wait
   to schedule a work item via workqueue. But if there is a bufio cache
   miss, or an error, then the tasklet will fallback to using workqueue.
 
 - Incremental changes to both dm-bufio and the DM verity target to use
   jump_label to minimize cost of branching associated with the niche
   "try_verify_in_tasklet" feature. DM-bufio in particular is used by
   quite a few other DM targets so it doesn't make sense to incur
   additional bufio cost in those targets purely for the benefit of
   this niche verity feature if the feature isn't ever used.
 
 - Optimize verity_verify_io, which is used by both workqueue and
   tasklet based verification, if FEC is not configured or tasklet
   based verification isn't used.
 
 - Remove DM verity target's verify_wq's use of the WQ_CPU_INTENSIVE
   flag since it uses WQ_UNBOUND. Also, use the WQ_HIGHPRI flag if
   "try_verify_in_tasklet" is specified.
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Merge tag 'for-6.0/dm-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull more device mapper updates from Mike Snitzer:

 - Add flags argument to dm_bufio_client_create and introduce
   DM_BUFIO_CLIENT_NO_SLEEP flag to have dm-bufio use spinlock rather
   than mutex for its locking.

 - Add optional "try_verify_in_tasklet" feature to DM verity target.
   This feature gives users the option to improve IO latency by using a
   tasklet to verify, using hashes in bufio's cache, rather than wait to
   schedule a work item via workqueue. But if there is a bufio cache
   miss, or an error, then the tasklet will fallback to using workqueue.

 - Incremental changes to both dm-bufio and the DM verity target to use
   jump_label to minimize cost of branching associated with the niche
   "try_verify_in_tasklet" feature. DM-bufio in particular is used by
   quite a few other DM targets so it doesn't make sense to incur
   additional bufio cost in those targets purely for the benefit of this
   niche verity feature if the feature isn't ever used.

 - Optimize verity_verify_io, which is used by both workqueue and
   tasklet based verification, if FEC is not configured or tasklet based
   verification isn't used.

 - Remove DM verity target's verify_wq's use of the WQ_CPU_INTENSIVE
   flag since it uses WQ_UNBOUND. Also, use the WQ_HIGHPRI flag if
   "try_verify_in_tasklet" is specified.

* tag 'for-6.0/dm-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm verity: have verify_wq use WQ_HIGHPRI if "try_verify_in_tasklet"
  dm verity: remove WQ_CPU_INTENSIVE flag since using WQ_UNBOUND
  dm verity: only copy bvec_iter in verity_verify_io if in_tasklet
  dm verity: optimize verity_verify_io if FEC not configured
  dm verity: conditionally enable branching for "try_verify_in_tasklet"
  dm bufio: conditionally enable branching for DM_BUFIO_CLIENT_NO_SLEEP
  dm verity: allow optional args to alter primary args handling
  dm verity: Add optional "try_verify_in_tasklet" feature
  dm bufio: Add DM_BUFIO_CLIENT_NO_SLEEP flag
  dm bufio: Add flags argument to dm_bufio_client_create
2022-08-06 11:09:55 -07:00
Linus Torvalds
6614a3c316 - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
 
 - Some kmemleak fixes from Patrick Wang and Waiman Long
 
 - DAMON updates from SeongJae Park
 
 - memcg debug/visibility work from Roman Gushchin
 
 - vmalloc speedup from Uladzislau Rezki
 
 - more folio conversion work from Matthew Wilcox
 
 - enhancements for coherent device memory mapping from Alex Sierra
 
 - addition of shared pages tracking and CoW support for fsdax, from
   Shiyang Ruan
 
 - hugetlb optimizations from Mike Kravetz
 
 - Mel Gorman has contributed some pagealloc changes to improve latency
   and realtime behaviour.
 
 - mprotect soft-dirty checking has been improved by Peter Xu
 
 - Many other singleton patches all over the place
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Merge tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Most of the MM queue. A few things are still pending.

  Liam's maple tree rework didn't make it. This has resulted in a few
  other minor patch series being held over for next time.

  Multi-gen LRU still isn't merged as we were waiting for mapletree to
  stabilize. The current plan is to merge MGLRU into -mm soon and to
  later reintroduce mapletree, with a view to hopefully getting both
  into 6.1-rc1.

  Summary:

   - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
     Lin, Yang Shi, Anshuman Khandual and Mike Rapoport

   - Some kmemleak fixes from Patrick Wang and Waiman Long

   - DAMON updates from SeongJae Park

   - memcg debug/visibility work from Roman Gushchin

   - vmalloc speedup from Uladzislau Rezki

   - more folio conversion work from Matthew Wilcox

   - enhancements for coherent device memory mapping from Alex Sierra

   - addition of shared pages tracking and CoW support for fsdax, from
     Shiyang Ruan

   - hugetlb optimizations from Mike Kravetz

   - Mel Gorman has contributed some pagealloc changes to improve
     latency and realtime behaviour.

   - mprotect soft-dirty checking has been improved by Peter Xu

   - Many other singleton patches all over the place"

 [ XFS merge from hell as per Darrick Wong in

   https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]

* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
  tools/testing/selftests/vm/hmm-tests.c: fix build
  mm: Kconfig: fix typo
  mm: memory-failure: convert to pr_fmt()
  mm: use is_zone_movable_page() helper
  hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
  hugetlbfs: cleanup some comments in inode.c
  hugetlbfs: remove unneeded header file
  hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
  hugetlbfs: use helper macro SZ_1{K,M}
  mm: cleanup is_highmem()
  mm/hmm: add a test for cross device private faults
  selftests: add soft-dirty into run_vmtests.sh
  selftests: soft-dirty: add test for mprotect
  mm/mprotect: fix soft-dirty check in can_change_pte_writable()
  mm: memcontrol: fix potential oom_lock recursion deadlock
  mm/gup.c: fix formatting in check_and_migrate_movable_page()
  xfs: fail dax mount if reflink is enabled on a partition
  mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
  userfaultfd: don't fail on unrecognized features
  hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
  ...
2022-08-05 16:32:45 -07:00