 */
struct net_device *netdev_master_upper_dev_get(struct net_device *dev)
{
	struct netdev_adjacent *upper;

	ASSERT_RTNL();

	if (list_empty(&dev->adj_list.upper))
		return NULL;

	upper = list_first_entry(&dev->adj_list.upper,
				 struct netdev_adjacent, list);
	if (likely(upper->master))
		return upper->dev;
	return NULL;
Unknown