[PATCH 8/8] block, bfq: don't grab queue_lock to initialize bfq

[Yu Kuai]

From: Yu Kuai <yukuai@xxxxxxx>

The request_queue is frozen and quiesced while the elevator init_sched()
method runs, so queue_lock is not needed for BFQ cgroup initialization.

Signed-off-by: Yu Kuai <yukuai@xxxxxxx>
---
 block/bfq-iosched.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 42ccfd0c6140..5cabee2d4e7c 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -7207,14 +7207,11 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_queue *eq)
 	bfqd = kzalloc_node(sizeof(*bfqd), GFP_KERNEL, q->node);
 	if (!bfqd)
 		return -ENOMEM;
 
 	eq->elevator_data = bfqd;
-
-	spin_lock_irq(&q->queue_lock);
 	q->elevator = eq;
-	spin_unlock_irq(&q->queue_lock);
 
 	/*
 	 * Our fallback bfqq if bfq_find_alloc_queue() runs into OOM issues.
 	 * Grab a permanent reference to it, so that the normal code flow
 	 * will not attempt to free it.
@@ -7243,11 +7240,10 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_queue *eq)
 	bfqd->num_actuators = 1;
 	/*
 	 * If the disk supports multiple actuators, copy independent
 	 * access ranges from the request queue structure.
 	 */
-	spin_lock_irq(&q->queue_lock);
 	if (ia_ranges) {
 		/*
 		 * Check if the disk ia_ranges size exceeds the current bfq
 		 * actuator limit.
 		 */
@@ -7269,11 +7265,10 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_queue *eq)
 	/* Otherwise use single-actuator dev info */
 	if (bfqd->num_actuators == 1) {
 		bfqd->sector[0] = 0;
 		bfqd->nr_sectors[0] = get_capacity(q->disk);
 	}
-	spin_unlock_irq(&q->queue_lock);
 
 	INIT_LIST_HEAD(&bfqd->dispatch);
 
 	hrtimer_setup(&bfqd->idle_slice_timer, bfq_idle_slice_timer, CLOCK_MONOTONIC,
 		      HRTIMER_MODE_REL);
-- 
2.51.0