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ALSA: usb-audio: scarlett2: Fix data_mutex lock

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[ Upstream commit 9b5ddea9ce5a68d7d2bedcb69901ac2a86c96c7b ]

The private->vol_updated flag was being checked outside of the
mutex_lock/unlock() of private->data_mutex leading to the volume data
being fetched twice from the device unnecessarily or old volume data
being returned.

Update scarlett2_*_ctl_get() and include the private->vol_updated flag
check inside the critical region.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/20210620164643.GA9216@m.b4.vu
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Geoffrey D. Bennett 2021-06-21 02:16:43 +09:30 committed by Greg Kroah-Hartman
parent 33251aa28d
commit f9e5d0137c
1 changed files with 9 additions and 12 deletions
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21
sound/usb/mixer_scarlett_gen2.c
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@ -1033,11 +1033,10 @@ static int scarlett2_master_volume_ctl_get(struct snd_kcontrol *kctl,
struct usb_mixer_interface *mixer = elem->head.mixer;
struct scarlett2_mixer_data *private = mixer->private_data;
if (private->vol_updated) {
mutex_lock(&private->data_mutex);
mutex_lock(&private->data_mutex);
if (private->vol_updated)
scarlett2_update_volumes(mixer);
mutex_unlock(&private->data_mutex);
}
mutex_unlock(&private->data_mutex);
ucontrol->value.integer.value[0] = private->master_vol;
return 0;
@ -1051,11 +1050,10 @@ static int scarlett2_volume_ctl_get(struct snd_kcontrol *kctl,
struct scarlett2_mixer_data *private = mixer->private_data;
int index = elem->control;
if (private->vol_updated) {
mutex_lock(&private->data_mutex);
mutex_lock(&private->data_mutex);
if (private->vol_updated)
scarlett2_update_volumes(mixer);
mutex_unlock(&private->data_mutex);
}
mutex_unlock(&private->data_mutex);
ucontrol->value.integer.value[0] = private->vol[index];
return 0;
@ -1319,11 +1317,10 @@ static int scarlett2_button_ctl_get(struct snd_kcontrol *kctl,
struct usb_mixer_interface *mixer = elem->head.mixer;
struct scarlett2_mixer_data *private = mixer->private_data;
if (private->vol_updated) {
mutex_lock(&private->data_mutex);
mutex_lock(&private->data_mutex);
if (private->vol_updated)
scarlett2_update_volumes(mixer);
mutex_unlock(&private->data_mutex);
}
mutex_unlock(&private->data_mutex);
ucontrol->value.enumerated.item[0] = private->buttons[elem->control];
return 0;