null_blk: fix memory leak on cleanup

Commit Message

Matias Bjørling Aug. 31, 2015, 12:17 p.m. UTC

From: Matias Bjørling <[e-mail]>

Driver was not freeing the memory allocated for internal nullb queues.
This patch frees the memory during driver unload.

Signed-off-by: Matias Bjørling <[e-mail]>
---
 drivers/block/null_blk.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

Comments

Ross Zwisler Sept. 2, 2015, 6:39 p.m. UTC | #1

On Mon, Aug 31, 2015 at 02:17:18PM +0200, Matias Bjørling wrote:
> From: Matias Bjørling <[e-mail]>
> 
> Driver was not freeing the memory allocated for internal nullb queues.
> This patch frees the memory during driver unload.

You may want to consider devm_* style allocations instead.  These are freed
automatically on driver unload, simplifying your error paths and your unload
logic as well as preventing leaks.

See this patch for an example:

https://lkml.org/lkml/2015/8/10/992
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Matias Bjørling Sept. 3, 2015, 5:48 a.m. UTC | #2

Den 02-09-2015 kl. 20:39 skrev Ross Zwisler:
> On Mon, Aug 31, 2015 at 02:17:18PM +0200, Matias Bjørling wrote:
>> From: Matias Bjørling <[e-mail]>
>>
>> Driver was not freeing the memory allocated for internal nullb queues.
>> This patch frees the memory during driver unload.
>
> You may want to consider devm_* style allocations instead.  These are freed
> automatically on driver unload, simplifying your error paths and your unload
> logic as well as preventing leaks.
>
> See this patch for an example:
>
> https://lkml.org/lkml/2015/8/10/992
>

Thanks for looking through the patches. I'll look into it.
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Patch

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 69de41a..90f6781 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -406,6 +406,22 @@  static struct blk_mq_ops null_mq_ops = {
 	.complete	= null_softirq_done_fn,
 };
 
+static void cleanup_queue(struct nullb_queue *nq)
+{
+	kfree(nq->tag_map);
+	kfree(nq->cmds);
+}
+
+static void cleanup_queues(struct nullb *nullb)
+{
+	int i;
+
+	for (i = 0; i < nullb->nr_queues; i++)
+		cleanup_queue(&nullb->queues[i]);
+
+	kfree(nullb->queues);
+}
+
 static void null_del_dev(struct nullb *nullb)
 {
 	list_del_init(&nullb->list);
@@ -415,6 +431,7 @@  static void null_del_dev(struct nullb *nullb)
 	if (queue_mode == NULL_Q_MQ)
 		blk_mq_free_tag_set(&nullb->tag_set);
 	put_disk(nullb->disk);
+	cleanup_queues(nullb);
 	kfree(nullb);
 }
 
@@ -459,22 +476,6 @@  static int setup_commands(struct nullb_queue *nq)
 	return 0;
 }
 
-static void cleanup_queue(struct nullb_queue *nq)
-{
-	kfree(nq->tag_map);
-	kfree(nq->cmds);
-}
-
-static void cleanup_queues(struct nullb *nullb)
-{
-	int i;
-
-	for (i = 0; i < nullb->nr_queues; i++)
-		cleanup_queue(&nullb->queues[i]);
-
-	kfree(nullb->queues);
-}
-
 static int setup_queues(struct nullb *nullb)
 {
 	nullb->queues = kzalloc(submit_queues * sizeof(struct nullb_queue),