[PATCH 4.9 189/191] ALSA: usb-audio: Fix invalid NULL check in snd_emuusb_set_samplerate()

Sasha Levin
2020-06-29T20:22:59Z

From: Takashi Iwai <tiwai@suse.de>

commit 6de3c9e3f6b3eaf66859e1379b3f35dda781416b upstream.

The quirk function snd_emuusb_set_samplerate() has a NULL check for
the mixer element, but this is useless in the current code. It used
to be a check against mixer->id_elems[unitid] but it was changed later
to the value after mixer_eleme_list_to_info() which is always non-NULL
due to the container_of() usage.

This patch fixes the check before the conversion.

While we're at it, correct a typo in the comment in the function,
too.

Fixes: 8c558076c740 ("ALSA: usb-audio: Clean up mixer element list traverse")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/usb/mixer_quirks.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 198515f86fcc2..9646513f4b4ad 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -1168,17 +1168,17 @@ void snd_emuusb_set_samplerate(struct snd_usb_audio *chip,
{
struct usb_mixer_interface *mixer;
struct usb_mixer_elem_info *cval;
- int unitid = 12; /* SamleRate ExtensionUnit ID */
+ int unitid = 12; /* SampleRate ExtensionUnit ID */

list_for_each_entry(mixer, &chip->mixer_list, list) {
- cval = mixer_elem_list_to_info(mixer->id_elems[unitid]);
- if (cval) {
+ if (mixer->id_elems[unitid]) {
+ cval = mixer_elem_list_to_info(mixer->id_elems[unitid]);
snd_usb_mixer_set_ctl_value(cval, UAC_SET_CUR,
cval->control << 8,
samplerate_id);
snd_usb_mixer_notify_id(mixer, unitid);
+ break;
}
- break;
}
}

--
2.25.1