Re: [PATCH v2] ALSA: control: preserve snd_card_file_add() error code in snd_ctl_open()

[Cezary Rojewski]

On 7/8/2026 4:35 AM, phucduc.bui@xxxxxxxxx wrote:
> From: bui duc phuc <phucduc.bui@xxxxxxxxx>
>
> snd_ctl_open() unconditionally overwrites the return value of
> snd_card_file_add() with -ENODEV on failure, discarding the actual
> error code.
>
> Fix this by directly returning the original error code returned by
> snd_card_file_add() (e.g. -ENOMEM or -ENODEV). This behavior is
> consistent with the error handling used in other functions such as
> snd_mixer_oss_open(), snd_hwdep_open(), snd_pcm_oss_open(), and others.
>
> There is no functional change other than the returned error code in this
> failure path.

BTW, as you've provided a number of positive contributions, a tip for 
future:

The change is simple and does not relate to any workaround or some kind 
of 'recommended' sequence.  And thus there's no need to be as verbose. 
IMHO the first paragraph suffices - explicitly answers the _why_ question.

The last is completely redundant - return code is a functional change. 
Similarly, "Fix this by (...)" in context of such a simple change yields 
no value for the reader - we see _what_ is happening clearly in the code.
> Signed-off-by: bui duc phuc <phucduc.bui@xxxxxxxxx>
> ---
>
> Changes in v2:
>   - Update commit messages.
>   - Drop superfluous braces.
>
>   sound/core/control.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/sound/core/control.c b/sound/core/control.c
> index 0ca9fff56e51..73d7ba0f509f 100644
> --- a/sound/core/control.c
> +++ b/sound/core/control.c
> @@ -63,10 +63,8 @@ static int snd_ctl_open(struct inode *inode, struct file *file)
>   		goto __error1;
>   	}
>   	err = snd_card_file_add(card, file);
> -	if (err < 0) {
> -		err = -ENODEV;
> +	if (err < 0)
>   		goto __error1;
> -	}
>   	if (!try_module_get(card->module)) {
>   		err = -ENODEV;
>   		goto __error2;