ALSA: Fix allocation size calculation in snd_dma_alloc_pages_fallback()

snd_dma_alloc_pages_fallback() always tries to reduce the size in a half,
but it's not good when the given size isn't a power-of-two.
Check it first then try to align.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

1 files changed, 6 insertions, 1 deletions

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index f0c3b1d6da8..a7b46ec72f3 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -277,11 +277,16 @@ int snd_dma_alloc_pages_fallback(int type, struct device *device, size_t size,
         int err;
 
         while ((err = snd_dma_alloc_pages(type, device, size, dmab)) < 0) {
+                size_t aligned_size;
                 if (err != -ENOMEM)
                         return err;
-                size >>= 1;
                 if (size <= PAGE_SIZE)
                         return -ENOMEM;
+                aligned_size = PAGE_SIZE << get_order(size);
+                if (size != aligned_size)
+                        size = aligned_size;
+                else
+                        size >>= 1;
         }
         if (! dmab->area)
                 return -ENOMEM;