ALSA: usb-audio: use list_for_each_entry_continue_reverse

For better readability, use list_for_each_entry_continue_reverse()
in have_dup_chmap().

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 8ee14f2365e749d964c369acef5ac45f95a060ca..c4dc577ab1bd3536193284bd6f6386e48fe59125 100644 (file)
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -125,11 +125,9 @@ static int usb_chmap_ctl_info(struct snd_kcontrol *kcontrol,
 static bool have_dup_chmap(struct snd_usb_substream *subs,
                           struct audioformat *fp)
 {
-       struct list_head *p;
+       struct audioformat *prev = fp;
 
-       for (p = fp->list.prev; p != &subs->fmt_list; p = p->prev) {
-               struct audioformat *prev;
-               prev = list_entry(p, struct audioformat, list);
+       list_for_each_entry_continue_reverse(prev, &subs->fmt_list, list) {
                if (prev->chmap &&
                    !memcmp(prev->chmap, fp->chmap, sizeof(*fp->chmap)))
                        return true;