diff options
| author | Ming Lei <ming.lei@redhat.com> | 2023-12-19 02:28:33 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-01-05 00:08:54 +0100 |
| commit | 393cd8ffd832f23eec3a105553eff622e8198918 (patch) | |
| tree | b37dc63e9f9e593a4128b326ac63077056ee8650 /block | |
| parent | blk-cgroup: don't use removal safe list iterators (diff) | |
| download | linux-393cd8ffd832f23eec3a105553eff622e8198918.tar.xz linux-393cd8ffd832f23eec3a105553eff622e8198918.zip | |
blk-cgroup: fix rcu lockdep warning in blkg_lookup()
blkg_lookup() is called with either queue_lock or rcu read lock, so
use rcu_dereference_check(lockdep_is_held(&q->queue_lock)) for
retrieving 'blkg', which way models the check exactly for covering
queue lock or rcu read lock.
Fix lockdep warning of "block/blk-cgroup.h:254 suspicious rcu_dereference_check() usage!"
from blkg_lookup().
Tested-by: Changhui Zhong <czhong@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Fixes: 83462a6c971c ("blkcg: Drop unnecessary RCU read [un]locks from blkg_conf_prep/finish()")
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20231219012833.2129540-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-cgroup.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index fd482439afbc..b927a4a0ad03 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -252,7 +252,8 @@ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, if (blkcg == &blkcg_root) return q->root_blkg; - blkg = rcu_dereference(blkcg->blkg_hint); + blkg = rcu_dereference_check(blkcg->blkg_hint, + lockdep_is_held(&q->queue_lock)); if (blkg && blkg->q == q) return blkg; |