[PATCH] ALSA: pcm: Fix mmap capability check

[Jaroslav Kysela]

On 20. 07. 21 11:26, Takashi Iwai wrote:
> The hw_support_mmap() doesn't cover all memory allocation types and
> might use a wrong device pointer for checking the capability.
> Check the all memory allocation types more completely.

This change breaks mmap for the snd-dummy driver (fake_buffer). It seems that
we need this fix?

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 6a2971a7e6a1..09c0e2a6489c 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -246,7 +246,7 @@ static bool hw_support_mmap(struct snd_pcm_substream
*substream)
        if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_MMAP))
                return false;

-       if (substream->ops->mmap)
+       if (substream->ops->mmap || substream->ops->page)
                return true;

        switch (substream->dma_buffer.dev.type) {


					Jaroslav


> 
> Cc: <stable at vger.kernel.org>
> Signed-off-by: Takashi Iwai <tiwai at suse.de>
> ---
>  sound/core/pcm_native.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> index c88c4316c417..6919d2943b9d 100644
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
> @@ -246,12 +246,18 @@ static bool hw_support_mmap(struct snd_pcm_substream *substream)
>  	if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_MMAP))
>  		return false;
>  
> -	if (substream->ops->mmap ||
> -	    (substream->dma_buffer.dev.type != SNDRV_DMA_TYPE_DEV &&
> -	     substream->dma_buffer.dev.type != SNDRV_DMA_TYPE_DEV_UC))
> +	if (substream->ops->mmap)
>  		return true;
>  
> -	return dma_can_mmap(substream->dma_buffer.dev.dev);
> +	switch (substream->dma_buffer.dev.type) {
> +	case SNDRV_DMA_TYPE_UNKNOWN:
> +		return false;
> +	case SNDRV_DMA_TYPE_CONTINUOUS:
> +	case SNDRV_DMA_TYPE_VMALLOC:
> +		return true;
> +	default:
> +		return dma_can_mmap(substream->dma_buffer.dev.dev);
> +	}
>  }
>  
>  static int constrain_mask_params(struct snd_pcm_substream *substream,
> 


-- 
Jaroslav Kysela <perex at perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.