DMA-API: sound: fix dma mask handling in a lot of drivers

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.

Acked-by: Mark Brown <broonie@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 4 insertions, 6 deletions

diff --git a/sound/soc/blackfin/bf5xx-i2s-pcm.c b/sound/soc/blackfin/bf5xx-i2s-pcm.c
index 9cb4a80df98e..2a5b43417fd5 100644
--- a/sound/soc/blackfin/bf5xx-i2s-pcm.c
+++ b/sound/soc/blackfin/bf5xx-i2s-pcm.c
@@ -323,18 +323,16 @@ static struct snd_pcm_ops bf5xx_pcm_i2s_ops = {
 	.silence	= bf5xx_pcm_silence,
 };
 
-static u64 bf5xx_pcm_dmamask = DMA_BIT_MASK(32);
-
 static int bf5xx_pcm_i2s_new(struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_card *card = rtd->card->snd_card;
 	size_t size = bf5xx_pcm_hardware.buffer_bytes_max;
+	int ret;
 
 	pr_debug("%s enter\n", __func__);
-	if (!card->dev->dma_mask)
-		card->dev->dma_mask = &bf5xx_pcm_dmamask;
-	if (!card->dev->coherent_dma_mask)
-		card->dev->coherent_dma_mask = DMA_BIT_MASK(32);
+	ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
 
 	return snd_pcm_lib_preallocate_pages_for_all(rtd->pcm,
 				SNDRV_DMA_TYPE_DEV, card->dev, size, size);