block: fix leak of q->rq_wb

CONFIG_DEBUG_TEST_DRIVER_REMOVE found a possible leak of q->rq_wb when a
request queue is reregistered. This has been a problem since wbt was
introduced, but the WARN_ON(!list_empty(&stats->callbacks)) in the
blk-stat rework exposed it. Fix it by cleaning up wbt when we unregister
the queue.

Fixes: 87760e5eef ("block: hook up writeback throttling")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Omar Sandoval 2017-03-28 16:12:17 -07:00 committed by Jens Axboe
parent 0c9539a431
commit 02ba8893ac

View File

@ -795,7 +795,6 @@ static void blk_release_queue(struct kobject *kobj)
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
wbt_exit(q);
if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
blk_stat_remove_callback(q, q->poll_cb);
blk_stat_free_callback(q->poll_cb);
@ -938,6 +937,9 @@ void blk_unregister_queue(struct gendisk *disk)
queue_flag_clear_unlocked(QUEUE_FLAG_REGISTERED, q);
wbt_exit(q);
if (q->mq_ops)
blk_mq_unregister_dev(disk_to_dev(disk), q);