[PATCH RFC v3 0/3] bugfix for sbitmap

[Yu Kuai]

Changes in v3:
 - rename patch 2, and add some comments.
 - add patch 3, which fixes a new issue pointed out by Jan Kara.
Changes in v2:
 - split to spearate patches for different problem.
 - add fix tag

This patchset fixes problems in the wakeup path on concurrent scenarios,
the problems are found during code review, and it's not reporduced in
real test yet in my environment.

Keith reported a possible related io hung problem in nvme:

https://bugzilla.kernel.org/show_bug.cgi?id=215679

Previous versions:
v1: https://lore.kernel.org/all/20220617141125.3024491-1-yukuai3@xxxxxxxxxx/
v2: https://lore.kernel.org/all/20220619080309.1630027-1-yukuai3@xxxxxxxxxx/

Yu Kuai (3):
  sbitmap: fix that same waitqueue can be woken up continuously
  sbitmap: fix invalid wakeup on the wrong waitqueue
  sbitmap: fix that 'wait_cnt' can be decreased while waitqueue is empty

 lib/sbitmap.c | 70 +++++++++++++++++++++++++++++++--------------------
 1 file changed, 43 insertions(+), 27 deletions(-)

-- 
2.31.1