[PATCH 3/4] block: null_blk: fix queue leak inside removing device

From: Ming Lei
Date: Mon Dec 23 2013 - 11:19:50 EST


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.

Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx>
---
drivers/block/null_blk.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index a2e69d2..83a598e 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);
--
1.7.9.5

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