netdev_upper_dev_link (9) - Linux Man Pages
netdev_upper_dev_link: Add a link to the upper device
netdev_upper_dev_link - Add a link to the upper device
int netdev_upper_dev_link(struct net_device
*dev, struct net_device *upper_dev);
- new upper device
Adds a link to device which is upper to this one. The caller must hold the RTNL lock. On a failure a negative errno code is returned. On success the reference counts are adjusted and the function returns zero.