[PATCH 3.16 050/254] ALSA: usb-audio: Add check return value for usb_string()

Ben Hutchings
2018-02-28T17:00:59Z

From: Jaejoong Kim <climbbb.kim@gmail.com>

commit 89b89d121ffcf8d9546633b98ded9d18b8f75891 upstream.

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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
sound/usb/mixer.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2100,13 +2100,14 @@ static int parse_audio_selector_unit(str
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");