blkcg: drop unnecessary RCU locking

[mirror_ubuntu-zesty-kernel.git] / block / blk-throttle.c

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index e35ee7aeea691a5750e6c6048309100a8fb2d1a2..bfa5168249eba067f2342ab2cf51a0f94f04e73f 100644 (file)
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1046,39 +1046,8 @@ int blk_throtl_init(struct request_queue *q)
 
 void blk_throtl_exit(struct request_queue *q)
 {
-       struct throtl_data *td = q->td;
-       bool wait;
-
-       BUG_ON(!td);
-
+       BUG_ON(!q->td);
        throtl_shutdown_wq(q);
-
-       /* If there are other groups */
-       spin_lock_irq(q->queue_lock);
-       wait = q->nr_blkgs;
-       spin_unlock_irq(q->queue_lock);
-
-       /*
-        * Wait for tg_to_blkg(tg)->q accessors to exit their grace periods.
-        * Do this wait only if there are other undestroyed groups out
-        * there (other than root group). This can happen if cgroup deletion
-        * path claimed the responsibility of cleaning up a group before
-        * queue cleanup code get to the group.
-        *
-        * Do not call synchronize_rcu() unconditionally as there are drivers
-        * which create/delete request queue hundreds of times during scan/boot
-        * and synchronize_rcu() can take significant time and slow down boot.
-        */
-       if (wait)
-               synchronize_rcu();
-
-       /*
-        * Just being safe to make sure after previous flush if some body did
-        * update limits through cgroup and another work got queued, cancel
-        * it.
-        */
-       throtl_shutdown_wq(q);
-
        kfree(q->td);
 }