Pull device mapper fixes from Mike Snitzer:

 - Fix DM thin to work as a swap device by using 'limit_swap_bios' DM
   target flag (initially added to allow swap to dm-crypt) to throttle
   the amount of outstanding swap bios.

 - Fix DM crypt soft lockup warnings by calling cond_resched() from the
   cpu intensive loop in dmcrypt_write().

 - Fix DM crypt to not access an uninitialized tasklet. This fix allows
   for consistent handling of IO completion, by _not_ needlessly punting
   to a workqueue when tasklets are not needed.

 - Fix DM core's alloc_dev() initialization for DM stats to check for
   and propagate alloc_percpu() failure.

* tag 'for-6.3/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm stats: check for and propagate alloc_percpu failure
  dm crypt: avoid accessing uninitialized tasklet
  dm crypt: add cond_resched() to dmcrypt_write()
  dm thin: fix deadlock when swapping to thin device

When neither "no_read_workqueue" nor "no_write_workqueue" are enabled,
tasklet_trylock() in crypt_dec_pending() may still return false due to
an uninitialized state, and dm-crypt will unnecessarily do io completion
in io_queue workqueue instead of current context.

Fix this by adding an 'in_tasklet' flag to dm_crypt_io struct and
initialize it to false in crypt_io_init(). Set this flag to true in
kcryptd_queue_crypt() before calling tasklet_schedule(). If set
crypt_dec_pending() will punt io completion to a workqueue.

This also nicely avoids the tasklet_trylock/unlock hack when tasklets
aren't in use.

Fixes: 8e14f610159d ("dm crypt: do not call bio_endio() from the dm-crypt tasklet")
Cc: stable@vger.kernel.org
Reported-by: Hou Tao <houtao1@huawei.com>
Suggested-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

The loop in dmcrypt_write may be running for unbounded amount of time,
thus we need cond_resched() in it.

This commit fixes the following warning:

[ 3391.153255][   C12] watchdog: BUG: soft lockup - CPU#12 stuck for 23s! [dmcrypt_write/2:2897]
...
[ 3391.387210][   C12] Call trace:
[ 3391.390338][   C12]  blk_attempt_bio_merge.part.6+0x38/0x158
[ 3391.395970][   C12]  blk_attempt_plug_merge+0xc0/0x1b0
[ 3391.401085][   C12]  blk_mq_submit_bio+0x398/0x550
[ 3391.405856][   C12]  submit_bio_noacct+0x308/0x380
[ 3391.410630][   C12]  dmcrypt_write+0x1e4/0x208 [dm_crypt]
[ 3391.416005][   C12]  kthread+0x130/0x138
[ 3391.419911][   C12]  ret_from_fork+0x10/0x18

Reported-by: yangerkun <yangerkun@huawei.com>
Fixes: dc2676210c42 ("dm crypt: offload writes to thread")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Pull device mapper updates from Mike Snitzer:

 - Fix DM cache target to free background tracker work items, otherwise
   slab BUG will occur when kmem_cache_destroy() is called.

 - Improve 2 of DM's shrinker names to reflect their use.

 - Fix the DM flakey target to not corrupt the zero page. Fix dm-flakey
   on 32-bit hughmem systems by using bvec_kmap_local instead of
   page_address. Also, fix logic used when imposing the
   "corrupt_bio_byte" feature.

 - Stop using WQ_UNBOUND for DM verity target's verify_wq because it
   causes significant Android latencies on ARM64 (and doesn't show real
   benefit on other architectures).

 - Add negative check to catch simple case of a DM table referencing
   itself. More complex scenarios that use intermediate devices to
   self-reference still need to be avoided/handled in userspace.

 - Fix DM core's resize to only send one uevent instead of two. This
   fixes a race with udev, that if udev wins, will cause udev to miss
   uevents (which caused premature unmount attempts by systemd).

 - Add cond_resched() to workqueue functions in DM core, dn-thin and
   dm-cache so that their loops aren't the cause of unintended cpu
   scheduling fairness issues.

 - Fix all of DM's checkpatch errors and warnings (famous last words).
   Various other small cleanups.

* tag 'for-6.3/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (62 commits)
  dm: remove unnecessary (void*) conversion in event_callback()
  dm ioctl: remove unnecessary check when using dm_get_mdptr()
  dm ioctl: assert _hash_lock is held in __hash_remove
  dm cache: add cond_resched() to various workqueue loops
  dm thin: add cond_resched() to various workqueue loops
  dm: add cond_resched() to dm_wq_requeue_work()
  dm: add cond_resched() to dm_wq_work()
  dm sysfs: make kobj_type structure constant
  dm: update targets using system workqueues to use a local workqueue
  dm: remove flush_scheduled_work() during local_exit()
  dm clone: prefer kvmalloc_array()
  dm: declare variables static when sensible
  dm: fix suspect indent whitespace
  dm ioctl: prefer strscpy() instead of strlcpy()
  dm: avoid void function return statements
  dm integrity: change macros min/max() -> min_t/max_t where appropriate
  dm: fix use of sizeof() macro
  dm: avoid 'do {} while(0)' loop in single statement macros
  dm log: avoid multiple line dereference
  dm log: avoid trailing semicolon in macro
  ...

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>