ALSA: pcm: Use __ffs() instead of ffs() in snd_mask_min()

The difference between __ffs and ffs is that ffs will return a one based
index whereas __ffs will return a zero based index. Furthermore ffs will
check if the passed value is zero and return zero in that case, whereas
__ffs behavior is undefined if the passed parameter is 0.

Since we already check if the mask is 0 before calling ffs and also subtract
1 from the result __ffs is the better choice.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/include/sound/pcm_params.h b/include/sound/pcm_params.h
index 042049b..c99e20b 100644 (file)
--- a/include/sound/pcm_params.h
+++ b/include/sound/pcm_params.h
@@ -92,7 +92,7 @@ static inline unsigned int snd_mask_min(const struct snd_mask *mask)
        int i;
        for (i = 0; i < SNDRV_MASK_SIZE; i++) {
                if (mask->bits[i])
-                       return ffs(mask->bits[i]) - 1 + (i << 5);
+                       return __ffs(mask->bits[i]) + (i << 5);
        }
        return 0;
 }