[PATCH] null_blk: fix return value from null_add_dev()

[PATCH] null_blk: fix return value from null_add_dev()

[Chaitanya Kulkarni]

The function nullb_device_power_store() returns -ENOMEM when
null_add_dev() fails. null_add_dev() can fail with return value
other than -ENOMEM such as -EINVAL when Zoned Block Device option
is used, see :

nullb_device_power_store()
 null_add_dev()
  null_init_zoned_dev()
	return -EINVAL;

When trying to load the module having -ENOMEM value returned on the
command line creates confusion when pleanty of memory is free on the
machine.

Instead of hardcoding -ENOMEM return the value of null_add_dev()
function.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
---
* without this patch nr_zones set to 23 :-

loading devices
++ seq 0 1
+ for i in `seq 0 $NN`
+ NULLB_DIR=config/nullb/nullb0
+ mkdir config/nullb/nullb0
+ echo 1
+ echo 23
+ echo 0
+ echo 1
+ echo 512
+ echo 2048
+ echo 1
./nullbtests.sh: line 23: echo: write error: Cannot allocate memory

* with this patch nr_zones set to 23 :-
+ for i in `seq 0 $NN`
+ NULLB_DIR=config/nullb/nullb1
+ mkdir config/nullb/nullb1
+ echo 1
+ echo 23
+ echo 1
+ echo 512
+ echo 2048
+ echo 1
./nullbtests.sh: line 23: echo: write error: Invalid argument

---
 drivers/block/null_blk/main.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 323af5c9c802..1666bd9c4ad7 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -431,9 +431,10 @@ static ssize_t nullb_device_power_store(struct config_item *item,
 	if (!dev->power && newp) {
 		if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
 			return count;
-		if (null_add_dev(dev)) {
+		ret = null_add_dev(dev);
+		if (ret) {
 			clear_bit(NULLB_DEV_FL_UP, &dev->flags);
-			return -ENOMEM;
+			return ret;
 		}
 
 		set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
-- 
2.29.0

Re: [PATCH] null_blk: fix return value from null_add_dev()

[Jens Axboe]

On Tue, 15 Feb 2022 03:59:51 -0800, Chaitanya Kulkarni wrote:
> The function nullb_device_power_store() returns -ENOMEM when
> null_add_dev() fails. null_add_dev() can fail with return value
> other than -ENOMEM such as -EINVAL when Zoned Block Device option
> is used, see :
> 
> nullb_device_power_store()
>  null_add_dev()
>   null_init_zoned_dev()
> 	return -EINVAL;
> 
> [...]

Applied, thanks!

[1/1] null_blk: fix return value from null_add_dev()
      (no commit info)

Best regards,
-- 
Jens Axboe