net/core/dev.c

9067 				   struct net_device *new_dev,
9077 	if (!new_dev)
9080 	if (old_dev && new_dev != old_dev)
9082 	err = __netdev_upper_dev_link(new_dev, dev, false, NULL, NULL, &priv,
9085 		if (old_dev && new_dev != old_dev)
9095 				   struct net_device *new_dev,
9103 	if (!new_dev || !old_dev)
9106 	if (new_dev == old_dev)
9115 				  struct net_device *new_dev,
9123 	if (!new_dev)
9126 	if (old_dev && new_dev != old_dev)
9129 	__netdev_upper_dev_unlink(new_dev, dev, &priv);