// from: http://kernelnewbies.org/KernelJanitors/Todo 
struct device {
	struct netdev_private *priv;
	struct netdev_private2 *priv2;

};

struct device *dev;

struct netdev_private *np = 
   dev->priv;


struct netdev_private *np2 = (struct netdev_private *)
   dev->priv2;


struct netdev_private *np3 = (struct netdev_private *) 
   dev;