diff options
| author | Yu Kuai <yukuai@fygo.io> | 2026-06-08 11:42:46 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-06-24 06:42:31 -0600 |
| commit | 457d3c4f0fdd6cf8a4bd8115bf470809984a9f02 (patch) | |
| tree | f2856a5fb261f7547b351d32411ae0f3633b3afd /block | |
| parent | 9327a865e395a53f67dffac4710beb1d4730495e (diff) | |
| download | ath-457d3c4f0fdd6cf8a4bd8115bf470809984a9f02.tar.gz | |
blk-cgroup: don't nest queue_lock under rcu in bio_associate_blkg()
If a bio is already associated with a blkg, the blkcg is already pinned
until the bio is done, so there is no need for RCU protection. Otherwise,
protect blkcg_css() with RCU independently. Prepare to protect blkcg with
blkcg_mutex instead of queue_lock.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
Link: https://patch.msgid.link/8496fa234b21d4b31b7f068766906d0bffcac8e6.1780621988.git.yukuai@fygo.io
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-cgroup.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index fee8c9d5dc2c0..e1bde48852ae1 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -2134,16 +2134,20 @@ void bio_associate_blkg(struct bio *bio) if (blk_op_is_passthrough(bio->bi_opf)) return; - rcu_read_lock(); - - if (bio->bi_blkg) + if (bio->bi_blkg) { css = bio_blkcg_css(bio); - else + bio_associate_blkg_from_css(bio, css); + } else { + rcu_read_lock(); css = blkcg_css(); + if (!css_tryget_online(css)) + css = NULL; + rcu_read_unlock(); - bio_associate_blkg_from_css(bio, css); - - rcu_read_unlock(); + bio_associate_blkg_from_css(bio, css); + if (css) + css_put(css); + } } EXPORT_SYMBOL_GPL(bio_associate_blkg); |