block: null_blk: fix queue leak inside removing device

When queue_mode is NULL_Q_MQ and null_blk is being removed,
blk_cleanup_queue() isn't called to cleanup queue, so the queue
allocated won't be freed.

This patch calls blk_cleanup_queue() for MQ to drain all pending
requests first and release the reference counter of queue kobject, then
blk_mq_free_queue() will be called in queue kobject's release handler
when queue kobject's reference counter drops to zero.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index a2e69d2..83a598e 100644 (file)
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -425,10 +425,7 @@ static void null_del_dev(struct nullb *nullb)
        list_del_init(&nullb->list);
 
        del_gendisk(nullb->disk);
-       if (queue_mode == NULL_Q_MQ)
-               blk_mq_free_queue(nullb->q);
-       else
-               blk_cleanup_queue(nullb->q);
+       blk_cleanup_queue(nullb->q);
        put_disk(nullb->disk);
        kfree(nullb);
 }
@@ -578,10 +575,7 @@ static int null_add_dev(void)
        disk = nullb->disk = alloc_disk_node(1, home_node);
        if (!disk) {
 queue_fail:
-               if (queue_mode == NULL_Q_MQ)
-                       blk_mq_free_queue(nullb->q);
-               else
-                       blk_cleanup_queue(nullb->q);
+               blk_cleanup_queue(nullb->q);
                cleanup_queues(nullb);
 err:
                kfree(nullb);