linux-toradex.git/drivers/md/raid5.c, branch v6.0-rc7

Merge tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-08-05T23:32:45+00:00

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
  ...

drivers:md:fix a potential use-after-free bug

2022-08-03T03:08:53+00:00

In line 2884, "raid5_release_stripe(sh);" drops the reference to sh and
may cause sh to be released. However, sh is subsequently used in lines
2886 "if (sh->batch_head && sh != sh->batch_head)". This may result in an
use-after-free bug.

It can be fixed by moving "raid5_release_stripe(sh);" to the bottom of
the function.

Signed-off-by: Wentao_Liang 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe

md/raid5: Ensure batch_last is released before sleeping for quiesce

2022-08-03T03:08:53+00:00

A race condition exists where if raid5_quiesce() is called in the
middle of a request that has set batch_last, it will deadlock.

batch_last will hold a reference to a stripe when raid5_quiesce() is
called. This will cause the next raid5_get_active_stripe() call to
sleep waiting for the quiesce to finish, but the raid5_quiesce() thread
will wait for active_stripes to go to zero which will never happen
because request thread is waiting for the quiesce to stop.

Fix this by creating a special __raid5_get_active_stripe() function
which takes the request context and clears the last_batch before
sleeping.

While we're at it, change the arguments of raid5_get_active_stripe()
to bools.

Fixes: 3312e6c887fe ("md/raid5: Keep a reference to last stripe_head for batch")
Reported-by: David Sloan 
Signed-off-by: Logan Gunthorpe 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe

md/raid5: Move stripe_request_ctx up

2022-08-03T03:08:53+00:00

Move stripe_request_ctx up. No functional changes intended.

This will be necessary in the next patch to release the batch_last
in the context before sleeping.

Signed-off-by: Logan Gunthorpe 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe

md/raid5: Drop unnecessary call to r5c_check_stripe_cache_usage()

2022-08-03T03:08:53+00:00

Now that raid5_get_active_stripe() has been refactored it is appearant
that r5c_check_stripe_cache_usage() doesn't need to be called in
the wait_for_stripe branch.

r5c_check_stripe_cache_usage() will only conditionally call
r5l_wake_reclaim(), but that function is called two lines later.

Drop the call for cleanup.

Reported-by: Martin Oliveira 
Signed-off-by: Logan Gunthorpe 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe

md/raid5: Make is_inactive_blocked() helper

2022-08-03T03:08:53+00:00

The logic to wait_for_stripe is difficult to parse being on so many
lines and with confusing operator precedence. Move it to a helper
function to make it easier to read.

No functional changes intended.

Signed-off-by: Logan Gunthorpe 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe

md/raid5: Refactor raid5_get_active_stripe()

2022-08-03T03:08:53+00:00

Refactor the raid5_get_active_stripe() to read more linearly in
the order it's typically executed.

The init_stripe() call is called if a free stripe is found and the
function is exited early which removes a lot of if (sh) checks and
unindents the following code.

Remove the while loop in favour of the 'goto retry' pattern, which
reduces indentation further. And use a 'goto wait_for_stripe' instead
of an additional indent seeing it is the unusual path and this makes
the code easier to read.

No functional changes intended. Will make subsequent changes
in patches easier to understand.

Signed-off-by: Logan Gunthorpe 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe

raid5: fix duplicate checks for rdev->saved_raid_disk

2022-08-02T23:22:46+00:00

'first' will always be greater than or equal to 0, it is unnecessary to
repeat the 0 check, clean it up.

Signed-off-by: Jackie Liu 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe

md/raid5: Convert prepare_to_wait() to wait_woken() api

2022-08-02T23:22:43+00:00

raid5_get_active_stripe() can sleep in various situations and it
is called by make_stripe_request() while inside the
prepare_to_wait()/finish_wait() section. Nested waits like this are
not supported.

This was noticed while making other changes that add different sleeps
to raid5_get_active_stripe() that caused a WARNING with
CONFIG_DEBUG_ATOMIC_SLEEP.

No ill effects have been noticed with the code as is, but theoretically
a nested and here could cause a dead lock so it should be fixed.

To fix this, convert the prepare_to_wait() call to use wake_woken()
which supports nested sleeps.

Link: https://lwn.net/Articles/628628/
Signed-off-by: Logan Gunthorpe 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe

md/raid5: Fix sectors_to_do bitmap overflow in raid5_make_request()

2022-08-02T23:22:41+00:00

For unaligned IO that have nearly maximum sectors, the number of stripes
will end up being one greater than the size of the bitmap. When this
happens, the last stripe in the IO will not be processed as it should
be, resulting in data corruption.

However, this is not normally seen when the backing block devices have
4K physical block sizes since the block layer will split the request
before that happens.

To fix this increase the bitmap size by one bit and ensure the full
number of stripes are checked when calling find_first_bit().

Reported-by: David Sloan 
Fixes: 7e55c60acfbb ("md/raid5: Pivot raid5_make_request()")
Signed-off-by: Logan Gunthorpe 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe