block: do more work in elevator_exit

Move the calls to ioc_clear_queue and blk_mq_sched_free_rqs into
elevator_exit.  Except for one call where we know we can't have io_cq
structures yet these always go together, and that extra call in an
error path is harmless.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220308055200.735835-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

block/elevator.c

@@ -192,6 +192,9 @@ void elevator_exit(struct request_queue *q)
 {
 	struct elevator_queue *e = q->elevator;
 
+	ioc_clear_queue(q);
+	blk_mq_sched_free_rqs(q);
+
 	mutex_lock(&e->sysfs_lock);
 	blk_mq_exit_sched(q, e);
 	mutex_unlock(&e->sysfs_lock);
@@ -596,8 +599,6 @@ int elevator_switch_mq(struct request_queue *q,
 
 	if (q->elevator) {
 		elv_unregister_queue(q);
-		ioc_clear_queue(q);
-		blk_mq_sched_free_rqs(q);
 		elevator_exit(q);
 	}
 
@@ -608,7 +609,6 @@ int elevator_switch_mq(struct request_queue *q,
 	if (new_e) {
 		ret = elv_register_queue(q, true);
 		if (ret) {
-			blk_mq_sched_free_rqs(q);
 			elevator_exit(q);
 			goto out;
 		}

block/genhd.c

@@ -1115,10 +1115,7 @@ static void disk_release_mq(struct request_queue *q)
 	 * cgroup controller.
 	 */
 	if (q->elevator) {
-		ioc_clear_queue(q);
-
 		mutex_lock(&q->sysfs_lock);
-		blk_mq_sched_free_rqs(q);
 		elevator_exit(q);
 		mutex_unlock(&q->sysfs_lock);
 	}