ALSA: usb-audio: Unify the release of usb_mixer_elem_info objects

Instead of the direct kfree() calls, introduce a new local helper to
release the usb_mixer_elem_info object.  This will be extended to do
more than a single kfree() in the later patches.

Also, use the standard goto instead of multiple calls in
parse_audio_selector_unit() error paths.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer.c

@@ -1026,10 +1026,15 @@ static struct usb_feature_control_info audio_feature_info[] = {
 	{ UAC2_FU_PHASE_INVERTER,	 "Phase Inverter Control", USB_MIXER_BOOLEAN, -1 },
 };
 
+static void usb_mixer_elem_info_free(struct usb_mixer_elem_info *cval)
+{
+	kfree(cval);
+}
+
 /* private_free callback */
 void snd_usb_mixer_elem_free(struct snd_kcontrol *kctl)
 {
-	kfree(kctl->private_data);
+	usb_mixer_elem_info_free(kctl->private_data);
 	kctl->private_data = NULL;
 }
 
@@ -1552,7 +1557,7 @@ static void __build_feature_ctl(struct usb_mixer_interface *mixer,
 
 	ctl_info = get_feature_control_info(control);
 	if (!ctl_info) {
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return;
 	}
 	if (mixer->protocol == UAC_VERSION_1)
@@ -1585,7 +1590,7 @@ static void __build_feature_ctl(struct usb_mixer_interface *mixer,
 
 	if (!kctl) {
 		usb_audio_err(mixer->chip, "cannot malloc kcontrol\n");
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return;
 	}
 	kctl->private_free = snd_usb_mixer_elem_free;
@@ -1755,7 +1760,7 @@ static void build_connector_control(struct usb_mixer_interface *mixer,
 	kctl = snd_ctl_new1(&usb_connector_ctl_ro, cval);
 	if (!kctl) {
 		usb_audio_err(mixer->chip, "cannot malloc kcontrol\n");
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return;
 	}
 	get_connector_control_name(mixer, term, is_input, kctl->id.name,
@@ -1808,7 +1813,7 @@ static int parse_clock_source_unit(struct mixer_build *state, int unitid,
 	kctl = snd_ctl_new1(&usb_bool_master_control_ctl_ro, cval);
 
 	if (!kctl) {
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return -ENOMEM;
 	}
 
@@ -2070,7 +2075,7 @@ static void build_mixer_unit_ctl(struct mixer_build *state,
 	kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval);
 	if (!kctl) {
 		usb_audio_err(state->chip, "cannot malloc kcontrol\n");
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return;
 	}
 	kctl->private_free = snd_usb_mixer_elem_free;
@@ -2468,7 +2473,7 @@ static int build_audio_procunit(struct mixer_build *state, int unitid,
 
 		kctl = snd_ctl_new1(&mixer_procunit_ctl, cval);
 		if (!kctl) {
-			kfree(cval);
+			usb_mixer_elem_info_free(cval);
 			return -ENOMEM;
 		}
 		kctl->private_free = snd_usb_mixer_elem_free;
@@ -2606,7 +2611,7 @@ static void usb_mixer_selector_elem_free(struct snd_kcontrol *kctl)
 	if (kctl->private_data) {
 		struct usb_mixer_elem_info *cval = kctl->private_data;
 		num_ins = cval->max;
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		kctl->private_data = NULL;
 	}
 	if (kctl->private_value) {
@@ -2678,22 +2683,19 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 		break;
 	}
 
-	namelist = kmalloc_array(desc->bNrInPins, sizeof(char *), GFP_KERNEL);
+	namelist = kcalloc(desc->bNrInPins, sizeof(char *), GFP_KERNEL);
 	if (!namelist) {
-		kfree(cval);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto error_cval;
 	}
 #define MAX_ITEM_NAME_LEN	64
 	for (i = 0; i < desc->bNrInPins; i++) {
 		struct usb_audio_term iterm;
 		len = 0;
 		namelist[i] = kmalloc(MAX_ITEM_NAME_LEN, GFP_KERNEL);
 		if (!namelist[i]) {
-			while (i--)
-				kfree(namelist[i]);
-			kfree(namelist);
-			kfree(cval);
-			return -ENOMEM;
+			err = -ENOMEM;
+			goto error_name;
 		}
 		len = check_mapped_selector_name(state, unitid, i, namelist[i],
 						 MAX_ITEM_NAME_LEN);
@@ -2707,10 +2709,8 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 	kctl = snd_ctl_new1(&mixer_selectunit_ctl, cval);
 	if (! kctl) {
 		usb_audio_err(state->chip, "cannot malloc kcontrol\n");
-		for (i = 0; i < desc->bNrInPins; i++)
-			kfree(namelist[i]);
-		kfree(namelist);
-		kfree(cval);
+		err = -ENOMEM;
+		goto error_name;
 		return -ENOMEM;
 	}
 	kctl->private_value = (unsigned long)namelist;
@@ -2757,6 +2757,14 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 	usb_audio_dbg(state->chip, "[%d] SU [%s] items = %d\n",
 		    cval->head.id, kctl->id.name, desc->bNrInPins);
 	return snd_usb_mixer_add_control(&cval->head, kctl);
+
+ error_name:
+	for (i = 0; i < desc->bNrInPins; i++)
+		kfree(namelist[i]);
+	kfree(namelist);
+ error_cval:
+	usb_mixer_elem_info_free(cval);
+	return err;
 }
 
 /*