Re: [PATCH 28/51] DMA-API: sound: fix dma mask handling in a lot of drivers
From: Takashi Iwai <hidden>
Date: 2013-09-26 08:29:39
Also in:
alsa-devel, dri-devel, linux-arm-kernel, linux-crypto, linux-devicetree, linux-ide, linux-mmc, linux-omap, linux-samsung-soc, linux-scsi, linux-tegra, linuxppc-dev
At Thu, 26 Sep 2013 10:25:13 +0200, Takashi Iwai wrote:
At Thu, 26 Sep 2013 08:54:25 +0100, Russell King - ARM Linux wrote:quoted
On Thu, Sep 26, 2013 at 09:51:23AM +0200, Takashi Iwai wrote:quoted
Hi, sorry for the lat response, as I've been traveling in the last weeks. At Thu, 19 Sep 2013 22:53:02 +0100, Russell King wrote:quoted
This code sequence is unsafe in modules: static u64 mask = DMA_BIT_MASK(something); ... if (!dev->dma_mask) dev->dma_mask = &mask; as if a module is reloaded, the mask will be pointing at the original module's mask address, and this can lead to oopses. Moreover, they all follow this with: if (!dev->coherent_dma_mask) dev->coherent_dma_mask = mask; where 'mask' is the same value as the statically defined mask, and this bypasses the architecture's check on whether the DMA mask is possible. Fix these issues by using the new dma_coerce_coherent_and_mask() function. Signed-off-by: Russell King <redacted>Applied with Mark's ack now.Which is a very stupid thing to do because you won't have dma_coerce_coherent_and_mask() in your tree, so all these drivers will fail to build for you.Ah, silly me, I missed the very first thing. Reverted it now... FWIW, below is the missing piece. Please apply it in your side if necessary.
Oh, and feel free to add my ack, if any: Acked-by: Takashi Iwai <redacted> thanks, Takashi
quoted hunk ↗ jump to hunk
Takashi --- sound/soc/fsl/imx-pcm-fiq.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)diff --git a/sound/soc/fsl/imx-pcm-fiq.c b/sound/soc/fsl/imx-pcm-fiq.c index 34043c5..fd5f2fb 100644 --- a/sound/soc/fsl/imx-pcm-fiq.c +++ b/sound/soc/fsl/imx-pcm-fiq.c@@ -272,18 +272,16 @@ static int imx_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream) return 0; } -static u64 imx_pcm_dmamask = DMA_BIT_MASK(32); - static int imx_pcm_new(struct snd_soc_pcm_runtime *rtd) { struct snd_card *card = rtd->card->snd_card; struct snd_pcm *pcm = rtd->pcm; - int ret = 0; + int ret; + + ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32)); + if (ret) + return ret; - if (!card->dev->dma_mask) - card->dev->dma_mask = &imx_pcm_dmamask; - if (!card->dev->coherent_dma_mask) - card->dev->coherent_dma_mask = DMA_BIT_MASK(32); if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) { ret = imx_pcm_preallocate_dma_buffer(pcm, SNDRV_PCM_STREAM_PLAYBACK);-- 1.8.4