netdevice: add ieee802154_ptr to net_device

This patch adds an ieee802154_ptr to the net_device structure.
Furthermore the 802.15.4 subsystem will introduce a nl802154 framework
which is similar like the nl80211 framework and a wpan_dev structure.
The wpan_dev structure will hold additional net_device attributes like
address options which are 802.15.4 specific. In the upcoming nl802154
implementation we will introduce a NL802154_FLAG_NEED_WPAN_DEV like
NL80211_FLAG_NEED_WDEV. For this flag an ieee802154_ptr in net_device is
needed. Additional we can access the wpan_dev attributes in upper layers
like IEEE 802.15.4 6LoWPAN easily. Current solution is a complicated
callback interface and getting these values over subif data structure
in mac802154.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/linux/netdevice.h

@@ -57,6 +57,8 @@ struct device;
 struct phy_device;
 /* 802.11 specific */
 struct wireless_dev;
+/* 802.15.4 specific */
+struct wpan_dev;
 
 void netdev_set_default_ethtool_ops(struct net_device *dev,
 				    const struct ethtool_ops *ops);
@@ -1572,6 +1574,7 @@ struct net_device {
 	struct inet6_dev __rcu	*ip6_ptr;
 	void			*ax25_ptr;
 	struct wireless_dev	*ieee80211_ptr;
+	struct wpan_dev		*ieee802154_ptr;
 
 /*
  * Cache lines mostly used on receive path (including eth_type_trans())