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authorMing Lei <ming.lei@redhat.com>2023-11-17 10:35:22 +0800
committerJens Axboe <axboe@kernel.dk>2023-11-17 10:48:58 -0700
commit27b13e209ddca5979847a1b57890e0372c1edcee (patch)
treea6bc8f395772ea9f4bb99df0ebb2140cbf8a5013 /block/blk-throttle.c
parentb0077e269f6c152e807fdac90b58caf012cdbaab (diff)
blk-throttle: fix lockdep warning of "cgroup_mutex or RCU read lock required!"
Inside blkg_for_each_descendant_pre(), both css_for_each_descendant_pre() and blkg_lookup() requires RCU read lock, and either cgroup_assert_mutex_or_rcu_locked() or rcu_read_lock_held() is called. Fix the warning by adding rcu read lock. Reported-by: Changhui Zhong <czhong@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20231117023527.3188627-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-throttle.c')
-rw-r--r--block/blk-throttle.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 13e4377a8b28..16f5766620a4 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1320,6 +1320,7 @@ static void tg_conf_updated(struct throtl_grp *tg, bool global)
tg_bps_limit(tg, READ), tg_bps_limit(tg, WRITE),
tg_iops_limit(tg, READ), tg_iops_limit(tg, WRITE));
+ rcu_read_lock();
/*
* Update has_rules[] flags for the updated tg's subtree. A tg is
* considered to have rules if either the tg itself or any of its
@@ -1347,6 +1348,7 @@ static void tg_conf_updated(struct throtl_grp *tg, bool global)
this_tg->latency_target = max(this_tg->latency_target,
parent_tg->latency_target);
}
+ rcu_read_unlock();
/*
* We're already holding queue_lock and know @tg is valid. Let's