[PATCH] ALSA: pcm: avoid nused-but-set-variable warning

[Takashi Sakamoto]

Hi,

On Wed, Nov 16, 2022 at 12:12:39AM +0000, Kuninori Morimoto wrote:
> 
> From: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
> 
> It will indicate below warning if W=1 was added and CONFIG_SND_DEBUG
> was not set. This patch adds __maybe_unused and avoid it.
> 
> 	${LINUX}/sound/core/pcm_native.c: In function 'constrain_mask_params':
> 	${LINUX}/sound/core/pcm_native.c:291:25: error: variable 'old_mask' set but not used [-Werror=unused-but-set-variable]
> 	  291 |         struct snd_mask old_mask;
> 	      |                         ^~~~~~~~
> 	${LINUX}/sound/core/pcm_native.c: In function 'constrain_interval_params':
> 	${LINUX}/sound/core/pcm_native.c:327:29: error: variable 'old_interval' set but not used [-Werror=unused-but-set-variable]
> 	  327 |         struct snd_interval old_interval;
> 	      |                             ^~~~~~~~~~~~
> 	${LINUX}/sound/core/pcm_native.c: In function 'constrain_params_by_rules':
> 	${LINUX}/sound/core/pcm_native.c:368:29: error: variable 'old_interval' set but not used [-Werror=unused-but-set-variable]
> 	  368 |         struct snd_interval old_interval;
> 	      |                             ^~~~~~~~~~~~
> 	${LINUX}/sound/core/pcm_native.c:367:25: error: variable 'old_mask' set but not used [-Werror=unused-but-set-variable]
> 	  367 |         struct snd_mask old_mask;
> 	      |                         ^~~~~~~~
> 	${LINUX}/sound/core/pcm_native.c: In function 'snd_pcm_hw_params_choose':
> 	${LINUX}/sound/core/pcm_native.c:652:29: error: variable 'old_interval' set but not used [-Werror=unused-but-set-variable]
> 	  652 |         struct snd_interval old_interval;
> 	      |                             ^~~~~~~~~~~~
> 	${LINUX}/sound/core/pcm_native.c:651:25: error: variable 'old_mask' set but not used [-Werror=unused-but-set-variable]
> 	  651 |         struct snd_mask old_mask;
> 	      |                         ^~~~~~~~
> 	cc1: all warnings being treated as errors
> 	make[3]: *** [${LINUX}/scripts/Makefile.build:250: sound/core/pcm_native.o] error 1
> 
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
> ---
>  sound/core/pcm_native.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)

Indeed. I think it a good catch.

Reviewed-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
Tested-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>

> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> index 33769ca78cc8..ba6e44d02faa 100644
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
> @@ -288,7 +288,7 @@ static int constrain_mask_params(struct snd_pcm_substream *substream,
>  					&substream->runtime->hw_constraints;
>  	struct snd_mask *m;
>  	unsigned int k;
> -	struct snd_mask old_mask;
> +	struct snd_mask old_mask __maybe_unused;
>  	int changed;
>  
>  	for (k = SNDRV_PCM_HW_PARAM_FIRST_MASK; k <= SNDRV_PCM_HW_PARAM_LAST_MASK; k++) {
> @@ -324,7 +324,7 @@ static int constrain_interval_params(struct snd_pcm_substream *substream,
>  					&substream->runtime->hw_constraints;
>  	struct snd_interval *i;
>  	unsigned int k;
> -	struct snd_interval old_interval;
> +	struct snd_interval old_interval __maybe_unused;
>  	int changed;
>  
>  	for (k = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++) {
> @@ -364,8 +364,8 @@ static int constrain_params_by_rules(struct snd_pcm_substream *substream,
>  	unsigned int stamp;
>  	struct snd_pcm_hw_rule *r;
>  	unsigned int d;
> -	struct snd_mask old_mask;
> -	struct snd_interval old_interval;
> +	struct snd_mask old_mask __maybe_unused;
> +	struct snd_interval old_interval __maybe_unused;
>  	bool again;
>  	int changed, err = 0;
>  
> @@ -648,8 +648,8 @@ static int snd_pcm_hw_params_choose(struct snd_pcm_substream *pcm,
>  		-1
>  	};
>  	const int *v;
> -	struct snd_mask old_mask;
> -	struct snd_interval old_interval;
> +	struct snd_mask old_mask __maybe_unused;
> +	struct snd_interval old_interval __maybe_unused;
>  	int changed;
>  
>  	for (v = vars; *v != -1; v++) {
> -- 
> 2.25.1

Regards

Takashi Sakamoto