[alsa-devel] [PATCH 2/2] ALSA: pcm: Allow aborting mutex lock at OSS read/write loops

[Lars-Peter Clausen]

On 01/08/2018 03:25 PM, Takashi Iwai wrote:
> @@ -1438,8 +1441,11 @@ static ssize_t snd_pcm_oss_read1(struct snd_pcm_substream *substream, char __use
>  
>  	if ((tmp = snd_pcm_oss_make_ready(substream)) < 0)
>  		return tmp;
> -	mutex_lock(&runtime->oss.params_lock);
>  	while (bytes > 0) {
> +		if (mutex_lock_interruptible(&runtime->oss.params_lock)) {
> +			tmp = -EINTR;

For consistency ERESTARTSYS I guess? In the end this is the same as
signal_pending().

> +			break;
> +		}
>  		if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) {
>  			if (runtime->oss.buffer_used == 0) {
>  				tmp = snd_pcm_oss_read2(substream, runtime->oss.buffer, runtime->oss.period_bytes, 1);
> @@ -1470,16 +1476,16 @@ static ssize_t snd_pcm_oss_read1(struct snd_pcm_substream *substream, char __use
>  			bytes -= tmp;
>  			xfer += tmp;
>  		}
> + err:
> +		mutex_unlock(&runtime->oss.params_lock);
> +		if (tmp < 0)
> +			break;
>  		if (signal_pending(current)) {
>  			tmp = -ERESTARTSYS;
> -			goto err;
> +			break;
>  		}
> +		tmp = 0;
>  	}
> -	mutex_unlock(&runtime->oss.params_lock);
> -	return xfer;
> -
> - err:
> -	mutex_unlock(&runtime->oss.params_lock);
>  	return xfer > 0 ? (snd_pcm_sframes_t)xfer : tmp;
>  }
>  
>