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>

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 8e18f7ec51f4b21e9461da41a49a47776808eb39..afc208e1c756f16bea4349d5fb80f5888bec99ba 100644 (file)
--- 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");