2023-02-16 01:39:53

by Jesper Juhl

Subject: [PATCH] Don't test for NULL firmware before releasing

From 4fe34831e2e7677b1c9616356f0a2e0a36ec092f Mon Sep 17 00:00:00 2001
From: Jesper Juhl <[email protected]>
Date: Thu, 16 Feb 2023 02:33:05 +0100
Subject: [PATCH] Don't test for NULL firmware before releasing

release_firmware() tests for a NULL pointer itself, no need to do it up-front.

Signed-off-by: Jesper Juhl <[email protected]>

---
drivers/gpu/drm/tegra/falcon.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/tegra/falcon.c b/drivers/gpu/drm/tegra/falcon.c
index c0d85463eb1a..ae599441f031 100644
--- a/drivers/gpu/drm/tegra/falcon.c
+++ b/drivers/gpu/drm/tegra/falcon.c
@@ -153,8 +153,7 @@ int falcon_init(struct falcon *falcon)

void falcon_exit(struct falcon *falcon)
{
- if (falcon->firmware.firmware)
- release_firmware(falcon->firmware.firmware);
+ release_firmware(falcon->firmware.firmware);
}

int falcon_boot(struct falcon *falcon)
--
2.39.2

2023-02-16 13:19:51

by Stanislaw Gruszka

Subject: Re: [PATCH] Don't test for NULL firmware before releasing

Hi

On Thu, Feb 16, 2023 at 02:37:15AM +0100, Jesper Juhl wrote:
> From 4fe34831e2e7677b1c9616356f0a2e0a36ec092f Mon Sep 17 00:00:00 2001
> From: Jesper Juhl <[email protected]>
> Date: Thu, 16 Feb 2023 02:33:05 +0100
> Subject: [PATCH] Don't test for NULL firmware before releasing
>
> release_firmware() tests for a NULL pointer itself, no need to do it up-front.
>
> Signed-off-by: Jesper Juhl <[email protected]>
>
> ---
> drivers/gpu/drm/tegra/falcon.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/tegra/falcon.c b/drivers/gpu/drm/tegra/falcon.c
> index c0d85463eb1a..ae599441f031 100644
> --- a/drivers/gpu/drm/tegra/falcon.c
> +++ b/drivers/gpu/drm/tegra/falcon.c
> @@ -153,8 +153,7 @@ int falcon_init(struct falcon *falcon)
>
> void falcon_exit(struct falcon *falcon)
> {
> - if (falcon->firmware.firmware)
> - release_firmware(falcon->firmware.firmware);
> + release_firmware(falcon->firmware.firmware);

Please check patches with checkpatch.pl before posting.

Regards
Stanislaw

2023-02-17 12:04:34

by Mikko Perttunen

Subject: Re: [PATCH] Don't test for NULL firmware before releasing

On 2/16/23 15:19, Stanislaw Gruszka wrote:
> Hi
>
> On Thu, Feb 16, 2023 at 02:37:15AM +0100, Jesper Juhl wrote:
>> From 4fe34831e2e7677b1c9616356f0a2e0a36ec092f Mon Sep 17 00:00:00 2001
>> From: Jesper Juhl <[email protected]>
>> Date: Thu, 16 Feb 2023 02:33:05 +0100
>> Subject: [PATCH] Don't test for NULL firmware before releasing
>>
>> release_firmware() tests for a NULL pointer itself, no need to do it up-front.
>>
>> Signed-off-by: Jesper Juhl <[email protected]>
>>
>> ---
>> drivers/gpu/drm/tegra/falcon.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/tegra/falcon.c b/drivers/gpu/drm/tegra/falcon.c
>> index c0d85463eb1a..ae599441f031 100644
>> --- a/drivers/gpu/drm/tegra/falcon.c
>> +++ b/drivers/gpu/drm/tegra/falcon.c
>> @@ -153,8 +153,7 @@ int falcon_init(struct falcon *falcon)
>>
>> void falcon_exit(struct falcon *falcon)
>> {
>> - if (falcon->firmware.firmware)
>> - release_firmware(falcon->firmware.firmware);
>> + release_firmware(falcon->firmware.firmware);
>
> Please check patches with checkpatch.pl before posting.
>
> Regards
> Stanislaw
>

Aside the formatting deficiencies, I'm also not in favor of relying on
NULL checks inside callees since doing so removes contextual information
from the programmer; just looking at the code, it is easy to assume the
pointer cannot be NULL if there is no NULL check. Recently had a longer
thread about this in the context of kfree in TegraDRM.

Thanks
Mikko