usb: gadget: uvc: fix missing mutex_unlock() if kstrtou8() fails

If kstrtou8() fails, the mutex_unlock() is missed, move kstrtou8()
before mutex_lock() to fix it up.

Fixes: 0525210 ("usb: gadget: uvc: Allow definition of XUs in configfs")
Fixes: b3c839b ("usb: gadget: uvc: Make bSourceID read/write")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20230213070926.776447-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/uvc_configfs.c

@@ -590,17 +590,17 @@ static ssize_t uvcg_default_output_b_source_id_store(struct config_item *item,
 	int result;
 	u8 num;
 
+	result = kstrtou8(page, 0, &num);
+	if (result)
+		return result;
+
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
 
 	opts_item = group->cg_item.ci_parent->ci_parent->
 			ci_parent->ci_parent;
 	opts = to_f_uvc_opts(opts_item);
 	cd = &opts->uvc_output_terminal;
 
-	result = kstrtou8(page, 0, &num);
-	if (result)
-		return result;
-
 	mutex_lock(&opts->lock);
 	cd->bSourceID = num;
 	mutex_unlock(&opts->lock);
@@ -707,15 +707,15 @@ static ssize_t uvcg_extension_b_num_controls_store(struct config_item *item,
 	int ret;
 	u8 num;
 
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		return ret;
+
 	mutex_lock(su_mutex);
 
 	opts_item = item->ci_parent->ci_parent->ci_parent;
 	opts = to_f_uvc_opts(opts_item);
 
-	ret = kstrtou8(page, 0, &num);
-	if (ret)
-		return ret;
-
 	mutex_lock(&opts->lock);
 	xu->desc.bNumControls = num;
 	mutex_unlock(&opts->lock);
@@ -742,15 +742,15 @@ static ssize_t uvcg_extension_b_nr_in_pins_store(struct config_item *item,
 	int ret;
 	u8 num;
 
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		return ret;
+
 	mutex_lock(su_mutex);
 
 	opts_item = item->ci_parent->ci_parent->ci_parent;
 	opts = to_f_uvc_opts(opts_item);
 
-	ret = kstrtou8(page, 0, &num);
-	if (ret)
-		return ret;
-
 	mutex_lock(&opts->lock);
 
 	if (num == xu->desc.bNrInPins) {
@@ -795,15 +795,15 @@ static ssize_t uvcg_extension_b_control_size_store(struct config_item *item,
 	int ret;
 	u8 num;
 
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		return ret;
+
 	mutex_lock(su_mutex);
 
 	opts_item = item->ci_parent->ci_parent->ci_parent;
 	opts = to_f_uvc_opts(opts_item);
 
-	ret = kstrtou8(page, 0, &num);
-	if (ret)
-		return ret;
-
 	mutex_lock(&opts->lock);
 
 	if (num == xu->desc.bControlSize) {