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, 7 deletions

diff --git a/sound/soc/omap/omap-pcm.c b/sound/soc/omap/omap-pcm.c
index a11405de86e8..b8fa9862e54c 100644
--- a/sound/soc/omap/omap-pcm.c
+++ b/sound/soc/omap/omap-pcm.c
@@ -156,8 +156,6 @@ static struct snd_pcm_ops omap_pcm_ops = {
         .mmap           = omap_pcm_mmap,
 };
 
-static u64 omap_pcm_dmamask = DMA_BIT_MASK(64);
-
 static int omap_pcm_preallocate_dma_buffer(struct snd_pcm *pcm,
         int stream)
 {
@@ -202,12 +200,11 @@ static int omap_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;
 
-        if (!card->dev->dma_mask)
-                card->dev->dma_mask = &omap_pcm_dmamask;
-        if (!card->dev->coherent_dma_mask)
-                card->dev->coherent_dma_mask = DMA_BIT_MASK(64);
+        ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(64));
+        if (ret)
+                return ret;
 
         if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
                 ret = omap_pcm_preallocate_dma_buffer(pcm,