[PATCH] block: fix checking return value of blk_mq_init_queue

[PATCH] block: fix checking return value of blk_mq_init_queue

[Ming Lei]

Check IS_ERR_OR_NULL(return value) instead of just return value.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
 drivers/block/null_blk.c   |    2 +-
 drivers/block/nvme-core.c  |    2 +-
 drivers/block/virtio_blk.c |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index ae9f615..f73fc5a 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -530,7 +530,7 @@ static int null_add_dev(void)
 			goto out_cleanup_queues;
 
 		nullb->q = blk_mq_init_queue(&nullb->tag_set);
-		if (!nullb->q) {
+		if (IS_ERR_OR_NULL(nullb->q)) {
 			rv = -ENOMEM;
 			goto out_cleanup_tags;
 		}
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index b1d5d87..0d2fbe6 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1370,7 +1370,7 @@ static int nvme_alloc_admin_tags(struct nvme_dev *dev)
 			return -ENOMEM;
 
 		dev->admin_q = blk_mq_init_queue(&dev->admin_tagset);
-		if (!dev->admin_q) {
+		if (IS_ERR_OR_NULL(dev->admin_q)) {
 			blk_mq_free_tag_set(&dev->admin_tagset);
 			return -ENOMEM;
 		}
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 7ef7c09..d594db0 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -638,7 +638,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 		goto out_put_disk;
 
 	q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set);
-	if (!q) {
+	if (IS_ERR_OR_NULL(q)) {
 		err = -ENOMEM;
 		goto out_free_tags;
 	}
-- 
1.7.9.5

Re: [PATCH] block: fix checking return value of blk_mq_init_queue

[Jens Axboe]

On 01/02/2015 07:25 AM, Ming Lei wrote:
> Check IS_ERR_OR_NULL(return value) instead of just return value.

Thanks Ming, applied.

-- 
Jens Axboe

Re: [PATCH] block: fix checking return value of blk_mq_init_queue

[Al Viro]

On Fri, Jan 02, 2015 at 08:53:11AM -0700, Jens Axboe wrote:
> On 01/02/2015 07:25 AM, Ming Lei wrote:
> >Check IS_ERR_OR_NULL(return value) instead of just return value.
> 
> Thanks Ming, applied.

Umm...  Looking at the callers, I'd suggest making it _never_ return NULL -
it's always treates as ERR_PTR(-ENOMEM) anyway.  Then the checks would be
just IS_ERR(...).

IS_ERR_OR_NULL() is very often a sign of lousy calling conventions and
this case is no exception...

Re: [PATCH] block: fix checking return value of blk_mq_init_queue

[Jens Axboe]

On 01/02/2015 10:34 AM, Al Viro wrote:
> On Fri, Jan 02, 2015 at 08:53:11AM -0700, Jens Axboe wrote:
>> On 01/02/2015 07:25 AM, Ming Lei wrote:
>>> Check IS_ERR_OR_NULL(return value) instead of just return value.
>>
>> Thanks Ming, applied.
>
> Umm...  Looking at the callers, I'd suggest making it _never_ return NULL -
> it's always treates as ERR_PTR(-ENOMEM) anyway.  Then the checks would be
> just IS_ERR(...).
>
> IS_ERR_OR_NULL() is very often a sign of lousy calling conventions and
> this case is no exception...

I actually made that change when committing it:

http://git.kernel.dk/?p=linux-block.git;a=commit;h=35b489d32fcc37e8735f41aa794b24cf9d1e74f5


-- 
Jens Axboe