ALSA: pcm - Call pgprot_noncached() for vmalloc'ed buffers

pgprot_noncached() can be set for vmalloc'ed buffers safely, and we'd
need non-cached behavior more or less, even for the intermediate ring-
buffers.

Now snd_pcm_lib_mmap_vmalloc() is added as the common PCM mmap callback
that is coupled with snd_pcm_lib_alloc_vmalloc_buffer() & co.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 9 insertions, 0 deletions

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 5df0d21f18b3..88fff44702a4 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3176,6 +3176,15 @@ int snd_pcm_lib_mmap_iomem(struct snd_pcm_substream *substream,
 EXPORT_SYMBOL(snd_pcm_lib_mmap_iomem);
 #endif /* SNDRV_PCM_INFO_MMAP */
 
+/* mmap callback with pgprot_noncached */
+int snd_pcm_lib_mmap_noncached(struct snd_pcm_substream *substream,
+                               struct vm_area_struct *area)
+{
+        area->vm_page_prot = pgprot_noncached(area->vm_page_prot);
+        return snd_pcm_default_mmap(substream, area);
+}
+EXPORT_SYMBOL(snd_pcm_lib_mmap_noncached);
+
 /*
  * mmap DMA buffer
  */