ALSA: scarlett2: Add missing mutex lock around get meter levels

As scarlett2_meter_ctl_get() uses meter_level_map[], the data_mutex
should be locked while accessing it.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Fixes: 3473185f31df ("ALSA: scarlett2: Remap Level Meter values")
Link: https://lore.kernel.org/r/77e093c27402c83d0730681448fa4f57583349dd.1703001053.git.g@b4.vu
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c
index 8a60c2169259a24fa931c139aa02ea92b7c9cc67..a3cbeba7bd246c0624e70653ea99b8b61690779b 100644 (file)
--- a/sound/usb/mixer_scarlett2.c
+++ b/sound/usb/mixer_scarlett2.c
@@ -3880,10 +3880,12 @@ static int scarlett2_meter_ctl_get(struct snd_kcontrol *kctl,
        u16 meter_levels[SCARLETT2_MAX_METERS];
        int i, err;
 
+       mutex_lock(&private->data_mutex);
+
        err = scarlett2_usb_get_meter_levels(elem->head.mixer, elem->channels,
                                             meter_levels);
        if (err < 0)
-               return err;
+               goto unlock;
 
        /* copy & translate from meter_levels[] using meter_level_map[] */
        for (i = 0; i < elem->channels; i++) {
@@ -3898,7 +3900,10 @@ static int scarlett2_meter_ctl_get(struct snd_kcontrol *kctl,
                ucontrol->value.integer.value[i] = value;
        }
 
-       return 0;
+unlock:
+       mutex_unlock(&private->data_mutex);
+
+       return err;
 }
 
 static const struct snd_kcontrol_new scarlett2_meter_ctl = {