Commit 77c570a1 authored by Fanjun Kong's avatar Fanjun Kong Committed by Jens Axboe
Browse files

blk-cgroup: Remove unnecessary rcu_read_lock/unlock() 



spin_lock_irq/spin_unlock_irq contains preempt_disable/enable().
Which can serve as RCU read-side critical region, so remove
rcu_read_lock/unlock().

Signed-off-by: default avatarFanjun Kong <bh1scw@gmail.com>
Reviewed-by: default avatarMuchun Song <songmuchun@bytedance.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220516173930.159535-1-bh1scw@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3607849d

block/blk-cgroup.c

+1 −3
Original line number Diff line number Diff line
@@ -1278,14 +1278,13 @@ int blkcg_init_queue(struct request_queue *q) 
	preloaded = !radix_tree_preload(GFP_KERNEL);



	/* Make sure the root blkg exists. */

	rcu_read_lock();

	/* spin_lock_irq can serve as RCU read-side critical section. */

	spin_lock_irq(&q->queue_lock);

	blkg = blkg_create(&blkcg_root, q, new_blkg);

	if (IS_ERR(blkg))

		goto err_unlock;

	q->root_blkg = blkg;

	spin_unlock_irq(&q->queue_lock);

	rcu_read_unlock();



	if (preloaded)

		radix_tree_preload_end();
@@ -1311,7 +1310,6 @@ int blkcg_init_queue(struct request_queue *q) 
	return ret;

err_unlock:

	spin_unlock_irq(&q->queue_lock);

	rcu_read_unlock();

	if (preloaded)

		radix_tree_preload_end();

	return PTR_ERR(blkg);