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>

1 files changed, 2 insertions, 8 deletions

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index a2e69d26266d..83a598ebb65a 100644
--- 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);