net: make dev->master general

dev->master is now tightly connected to bonding driver. This patch makes
this pointer more general and ready to be used by others.

 - netdev_set_master() - bond specifics moved to new function
   netdev_set_bond_master()
 - introduced netif_is_bond_slave() to check if device is a bonding slave

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5a5baea..5a42b10 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2377,6 +2377,8 @@
 extern int		netdev_tstamp_prequeue;
 extern int		weight_p;
 extern int		netdev_set_master(struct net_device *dev, struct net_device *master);
+extern int netdev_set_bond_master(struct net_device *dev,
+				  struct net_device *master);
 extern int skb_checksum_help(struct sk_buff *skb);
 extern struct sk_buff *skb_gso_segment(struct sk_buff *skb, u32 features);
 #ifdef CONFIG_BUG
@@ -2437,6 +2439,11 @@
 	dev->gso_max_size = size;
 }
 
+static inline int netif_is_bond_slave(struct net_device *dev)
+{
+	return dev->flags & IFF_SLAVE && dev->priv_flags & IFF_BONDING;
+}
+
 extern struct pernet_operations __net_initdata loopback_net_ops;
 
 static inline int dev_ethtool_get_settings(struct net_device *dev,