ALSA: usb-audio: Add check return value for usb_string()

snd_usb_copy_string_desc() returns zero if usb_string() fails.
In case of failure, we need to check the snd_usb_copy_string_desc()'s
return value and add an exception case

Signed-off-by: Jaejoong Kim <climbbb.kim@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 5 insertions, 4 deletions

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 8e18f7ec51f4..afc208e1c756 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2178,13 +2178,14 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
         if (len)
                 ;
         else if (nameid)
-                snd_usb_copy_string_desc(state, nameid, kctl->id.name,
+                len = snd_usb_copy_string_desc(state, nameid, kctl->id.name,
                                          sizeof(kctl->id.name));
-        else {
+        else
                 len = get_term_name(state, &state->oterm,
                                     kctl->id.name, sizeof(kctl->id.name), 0);
-                if (!len)
-                        strlcpy(kctl->id.name, "USB", sizeof(kctl->id.name));
+
+        if (!len) {
+                strlcpy(kctl->id.name, "USB", sizeof(kctl->id.name));
 
                 if (desc->bDescriptorSubtype == UAC2_CLOCK_SELECTOR)
                         append_ctl_name(kctl, " Clock Source");