2023-11-02 14:12:09

by Alexandra Diupina

Subject: [PATCH 2/4] Remove redundant return value check

media_entity_pads_init() will not return 0 only if the
2nd parameter >= MEDIA_ENTITY_MAX_PADS (512), but 1 is
passed, so checking the return value is redundant

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 34009bffc1c6 ("media: i2c: Add RDACM20 driver")
Signed-off-by: Alexandra Diupina <[email protected]>
---
drivers/media/i2c/rdacm20.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c
index f4e2e2f3972a..ed249ade54e0 100644
--- a/drivers/media/i2c/rdacm20.c
+++ b/drivers/media/i2c/rdacm20.c
@@ -611,9 +611,7 @@ static int rdacm20_probe(struct i2c_client *client)

dev->pad.flags = MEDIA_PAD_FL_SOURCE;
dev->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
- ret = media_entity_pads_init(&dev->sd.entity, 1, &dev->pad);
- if (ret < 0)
- goto error_free_ctrls;
+ media_entity_pads_init(&dev->sd.entity, 1, &dev->pad);

ret = v4l2_async_register_subdev(&dev->sd);
if (ret)
--
2.30.2

2023-11-02 14:56:16

by Jacopo Mondi

Subject: Re: [PATCH 2/4] Remove redundant return value check

Hi Alexandra

On Thu, Nov 02, 2023 at 05:11:33PM +0300, Alexandra Diupina wrote:
> media_entity_pads_init() will not return 0 only if the
> 2nd parameter >= MEDIA_ENTITY_MAX_PADS (512), but 1 is
> passed, so checking the return value is redundant

I do also see

if (hweight32(iter->flags & (MEDIA_PAD_FL_SINK |
MEDIA_PAD_FL_SOURCE)) != 1) {
ret = -EINVAL;
break;
}

as a possible failure in in media_entity_pads_init().

>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 34009bffc1c6 ("media: i2c: Add RDACM20 driver")

And this does not really qualify as a fix imho

In general, being defensive and check for return errors in not a bad
thing. I would keep the check in place, it really doesn't hurt.

Same for the other patches in the series.

Thanks
j

> Signed-off-by: Alexandra Diupina <[email protected]>
> ---
> drivers/media/i2c/rdacm20.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c
> index f4e2e2f3972a..ed249ade54e0 100644
> --- a/drivers/media/i2c/rdacm20.c
> +++ b/drivers/media/i2c/rdacm20.c
> @@ -611,9 +611,7 @@ static int rdacm20_probe(struct i2c_client *client)
>
> dev->pad.flags = MEDIA_PAD_FL_SOURCE;
> dev->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> - ret = media_entity_pads_init(&dev->sd.entity, 1, &dev->pad);
> - if (ret < 0)
> - goto error_free_ctrls;
> + media_entity_pads_init(&dev->sd.entity, 1, &dev->pad);
>
> ret = v4l2_async_register_subdev(&dev->sd);
> if (ret)
> --
> 2.30.2
>

2023-11-02 15:38:42

by Laurent Pinchart

Subject: Re: [PATCH 2/4] Remove redundant return value check

On Thu, Nov 02, 2023 at 05:11:33PM +0300, Alexandra Diupina wrote:
> media_entity_pads_init() will not return 0 only if the
> 2nd parameter >= MEDIA_ENTITY_MAX_PADS (512), but 1 is
> passed, so checking the return value is redundant

That may be the case today, but may not be true tomorrow if the function
is extended to perform extra checks. I don't think dropping the error
check in drivers is a good idea.

> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 34009bffc1c6 ("media: i2c: Add RDACM20 driver")
> Signed-off-by: Alexandra Diupina <[email protected]>
> ---
> drivers/media/i2c/rdacm20.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c
> index f4e2e2f3972a..ed249ade54e0 100644
> --- a/drivers/media/i2c/rdacm20.c
> +++ b/drivers/media/i2c/rdacm20.c
> @@ -611,9 +611,7 @@ static int rdacm20_probe(struct i2c_client *client)
>
> dev->pad.flags = MEDIA_PAD_FL_SOURCE;
> dev->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> - ret = media_entity_pads_init(&dev->sd.entity, 1, &dev->pad);
> - if (ret < 0)
> - goto error_free_ctrls;
> + media_entity_pads_init(&dev->sd.entity, 1, &dev->pad);
>
> ret = v4l2_async_register_subdev(&dev->sd);
> if (ret)

--
Regards,

Laurent Pinchart