[PATCH 1/1] drm/nouveau: fix error return code in nouveau_backlight_init()

[PATCH 1/1] drm/nouveau: fix error return code in nouveau_backlight_init()

[Zhen Lei]

Fix to return a negative error code from the error handling case instead
of 0, as done elsewhere in this function.

Fixes: db1a0ae21461 ("drm/nouveau/bl: Assign different names to interfaces")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 drivers/gpu/drm/nouveau/nouveau_backlight.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c b/drivers/gpu/drm/nouveau/nouveau_backlight.c
index 72f35a2babcb..097ca344a086 100644
--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
+++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
@@ -273,6 +273,7 @@ nouveau_backlight_init(struct drm_connector *connector)
 		return -ENOMEM;
 
 	if (!nouveau_get_backlight_name(backlight_name, bl)) {
+		ret = -ENOSPC;
 		NV_ERROR(drm, "Failed to retrieve a unique name for the backlight interface\n");
 		goto fail_alloc;
 	}
-- 
2.25.1

Re: [PATCH 1/1] drm/nouveau: fix error return code in nouveau_backlight_init()

[Pierre Moreau]

Hello Zhen,

There was a similar patch sent in last month, though which does not seem to
have been merged yet; see
https://lists.freedesktop.org/archives/nouveau/2021-April/038451.html.

Whether `ret` should be `-ENOSPC` or `-ENOMEM` is hard to say as
`nouveau_get_backlight_name()` could fail due to either.

I will propose an alternative fix which modifies `nouveau_get_backlight_name()`
to return an int so the actual error code can be propagated back instead of
guessed, as well as fix an ida ID leak which I just spotted.

Best,
Pierre

On 2021-05-08 — 11:48, Zhen Lei wrote:
> Fix to return a negative error code from the error handling case instead
> of 0, as done elsewhere in this function.
> 
> Fixes: db1a0ae21461 ("drm/nouveau/bl: Assign different names to interfaces")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
>  drivers/gpu/drm/nouveau/nouveau_backlight.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c b/drivers/gpu/drm/nouveau/nouveau_backlight.c
> index 72f35a2babcb..097ca344a086 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
> @@ -273,6 +273,7 @@ nouveau_backlight_init(struct drm_connector *connector)
>  		return -ENOMEM;
>  
>  	if (!nouveau_get_backlight_name(backlight_name, bl)) {
> +		ret = -ENOSPC;
>  		NV_ERROR(drm, "Failed to retrieve a unique name for the backlight interface\n");
>  		goto fail_alloc;
>  	}
> -- 
> 2.25.1
> 
> 

Re: [PATCH 1/1] drm/nouveau: fix error return code in nouveau_backlight_init()

[Leizhen (ThunderTown)]

On 2021/5/8 15:34, Pierre Moreau wrote:
> Hello Zhen,
> 
> There was a similar patch sent in last month, though which does not seem to
> have been merged yet; see
> https://lists.freedesktop.org/archives/nouveau/2021-April/038451.html.
> 
> Whether `ret` should be `-ENOSPC` or `-ENOMEM` is hard to say as
> `nouveau_get_backlight_name()` could fail due to either.
> 
> I will propose an alternative fix which modifies `nouveau_get_backlight_name()`
> to return an int so the actual error code can be propagated back instead of
> guessed, as well as fix an ida ID leak which I just spotted.

It's a good idea.

> 
> Best,
> Pierre
> 
> On 2021-05-08 — 11:48, Zhen Lei wrote:
>> Fix to return a negative error code from the error handling case instead
>> of 0, as done elsewhere in this function.
>>
>> Fixes: db1a0ae21461 ("drm/nouveau/bl: Assign different names to interfaces")
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>> ---
>>  drivers/gpu/drm/nouveau/nouveau_backlight.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c b/drivers/gpu/drm/nouveau/nouveau_backlight.c
>> index 72f35a2babcb..097ca344a086 100644
>> --- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
>> +++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
>> @@ -273,6 +273,7 @@ nouveau_backlight_init(struct drm_connector *connector)
>>  		return -ENOMEM;
>>  
>>  	if (!nouveau_get_backlight_name(backlight_name, bl)) {
>> +		ret = -ENOSPC;
>>  		NV_ERROR(drm, "Failed to retrieve a unique name for the backlight interface\n");
>>  		goto fail_alloc;
>>  	}
>> -- 
>> 2.25.1
>>
>>
> 
> .
>