This is a note to let you know that I've just added the patch titled
blk-cgroup: avoid to warn !rcu_read_lock_held() in blkg_lookup()
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
blk-cgroup-avoid-to-warn-rcu_read_lock_held-in-blkg_.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fdb6785afbafe8981477a5cda947e5f2cc941d85
Author: Ming Lei <ming.lei@xxxxxxxxxx>
Date: Fri Nov 17 10:35:23 2023 +0800
blk-cgroup: avoid to warn !rcu_read_lock_held() in blkg_lookup()
[ Upstream commit 35a99d6557cacbc177314735342f77a2dda41872 ]
So far, all callers either holds spin lock or rcu read explicitly, and
most of the caller has added WARN_ON_ONCE(!rcu_read_lock_held()) or
lockdep_assert_held(&disk->queue->queue_lock).
Remove WARN_ON_ONCE(!rcu_read_lock_held()) from blkg_lookup() for
killing the false positive warning from blkg_conf_prep().
Reported-by: Changhui Zhong <czhong@xxxxxxxxxx>
Fixes: 83462a6c971c ("blkcg: Drop unnecessary RCU read [un]locks from blkg_conf_prep/finish()")
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231117023527.3188627-3-ming.lei@xxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 624c03c8fe64e..fd482439afbc9 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -249,8 +249,6 @@ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
{
struct blkcg_gq *blkg;
- WARN_ON_ONCE(!rcu_read_lock_held());
-
if (blkcg == &blkcg_root)
return q->root_blkg;
