From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Date: Mon, 05 Aug 2019 09:22:03 +0000 Subject: Re: [PATCH 4/7] ALSA: pcm: use dma_can_mmap() to check if a device supports dma_mmap_* Message-Id: List-Id: References: <20190805091159.7826-5-hch@lst.de> In-Reply-To: <20190805091159.7826-5-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sh@vger.kernel.org On Mon, 05 Aug 2019 11:11:56 +0200, Christoph Hellwig wrote: > > Replace the local hack with the dma_can_mmap helper to check if > a given device supports mapping DMA allocations to userspace. > > Signed-off-by: Christoph Hellwig > --- > sound/core/pcm_native.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c > index 703857aab00f..81c82c3ee8a2 100644 > --- a/sound/core/pcm_native.c > +++ b/sound/core/pcm_native.c > @@ -220,12 +220,11 @@ static bool hw_support_mmap(struct snd_pcm_substream *substream) > { > if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_MMAP)) > return false; > - /* architecture supports dma_mmap_coherent()? */ > -#if defined(CONFIG_ARCH_NO_COHERENT_DMA_MMAP) || !defined(CONFIG_HAS_DMA) > + if (!dma_can_mmap(substream->dma_buffer.dev.dev)) > + return false; > if (!substream->ops->mmap && > substream->dma_buffer.dev.type = SNDRV_DMA_TYPE_DEV) > return false; > -#endif This won't work as expected, unfortunately. It's a bit tricky check, since the driver may have its own mmap implementation via substream->ops->mmap, and the dma_buffer.dev.dev might point to another object depending on the dma_buffer.dev.type. So please replace with something like below: --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -221,11 +221,10 @@ static bool hw_support_mmap(struct snd_pcm_substream *substream) if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_MMAP)) return false; /* architecture supports dma_mmap_coherent()? */ -#if defined(CONFIG_ARCH_NO_COHERENT_DMA_MMAP) || !defined(CONFIG_HAS_DMA) if (!substream->ops->mmap && - substream->dma_buffer.dev.type = SNDRV_DMA_TYPE_DEV) + substream->dma_buffer.dev.type = SNDRV_DMA_TYPE_DEV && + !dma_can_mmap(substream->dma_buffer.dev.dev)) return false; -#endif return true; } Thanks! Takashi