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>

drivers/infiniband/hw/nes/nes.c

@@ -153,7 +153,8 @@ static int nes_inetaddr_event(struct notifier_block *notifier,
 				nesdev, nesdev->netdev[0]->name);
 		netdev = nesdev->netdev[0];
 		nesvnic = netdev_priv(netdev);
-		is_bonded = (netdev->master == event_netdev);
+		is_bonded = netif_is_bond_slave(netdev) &&
+			    (netdev->master == event_netdev);
 		if ((netdev == event_netdev) || is_bonded) {
 			if (nesvnic->rdma_enabled == 0) {
 				nes_debug(NES_DBG_NETDEV, "Returning without processing event for %s since"

drivers/infiniband/hw/nes/nes_cm.c

@@ -1118,7 +1118,7 @@ static int nes_addr_resolve_neigh(struct nes_vnic *nesvnic, u32 dst_ip, int arpi
 		return rc;
 	}
 
-	if (nesvnic->netdev->master)
+	if (netif_is_bond_slave(netdev))
 		netdev = nesvnic->netdev->master;
 	else
 		netdev = nesvnic->netdev;

drivers/net/bonding/bond_main.c

@@ -1594,9 +1594,9 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 		}
 	}
 
-	res = netdev_set_master(slave_dev, bond_dev);
+	res = netdev_set_bond_master(slave_dev, bond_dev);
 	if (res) {
-		pr_debug("Error %d calling netdev_set_master\n", res);
+		pr_debug("Error %d calling netdev_set_bond_master\n", res);
 		goto err_restore_mac;
 	}
 	/* open the slave since the application closed it */
@@ -1812,7 +1812,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	dev_close(slave_dev);
 
 err_unset_master:
-	netdev_set_master(slave_dev, NULL);
+	netdev_set_bond_master(slave_dev, NULL);
 
 err_restore_mac:
 	if (!bond->params.fail_over_mac) {
@@ -1992,7 +1992,7 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
 		netif_addr_unlock_bh(bond_dev);
 	}
 
-	netdev_set_master(slave_dev, NULL);
+	netdev_set_bond_master(slave_dev, NULL);
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	read_lock_bh(&bond->lock);
@@ -2114,7 +2114,7 @@ static int bond_release_all(struct net_device *bond_dev)
 			netif_addr_unlock_bh(bond_dev);
 		}
 
-		netdev_set_master(slave_dev, NULL);
+		netdev_set_bond_master(slave_dev, NULL);
 
 		/* close slave before restoring its mac address */
 		dev_close(slave_dev);

drivers/net/cxgb3/cxgb3_offload.c

@@ -186,9 +186,10 @@ static struct net_device *get_iff_from_mac(struct adapter *adapter,
 				dev = NULL;
 				if (grp)
 					dev = vlan_group_get_device(grp, vlan);
-			} else
+			} else if (netif_is_bond_slave(dev)) {
 				while (dev->master)
 					dev = dev->master;
+			}
 			return dev;
 		}
 	}

include/linux/netdevice.h

@@ -2377,6 +2377,8 @@ extern int		netdev_max_backlog;
 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 @@ static inline void netif_set_gso_max_size(struct net_device *dev,
 	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,

net/core/dev.c

@@ -3146,7 +3146,6 @@ static int __netif_receive_skb(struct sk_buff *skb)
 	struct packet_type *ptype, *pt_prev;
 	rx_handler_func_t *rx_handler;
 	struct net_device *orig_dev;
-	struct net_device *master;
 	struct net_device *null_or_orig;
 	struct net_device *orig_or_bond;
 	int ret = NET_RX_DROP;
@@ -3173,15 +3172,19 @@ static int __netif_receive_skb(struct sk_buff *skb)
 	 */
 	null_or_orig = NULL;
 	orig_dev = skb->dev;
-	master = ACCESS_ONCE(orig_dev->master);
 	if (skb->deliver_no_wcard)
 		null_or_orig = orig_dev;
-	else if (master) {
-		if (__skb_bond_should_drop(skb, master)) {
-			skb->deliver_no_wcard = 1;
-			null_or_orig = orig_dev; /* deliver only exact match */
-		} else
-			skb->dev = master;
+	else if (netif_is_bond_slave(orig_dev)) {
+		struct net_device *bond_master = ACCESS_ONCE(orig_dev->master);
+
+		if (likely(bond_master)) {
+			if (__skb_bond_should_drop(skb, bond_master)) {
+				skb->deliver_no_wcard = 1;
+				/* deliver only exact match */
+				null_or_orig = orig_dev;
+			} else
+				skb->dev = bond_master;
+		}
 	}
 
 	__this_cpu_inc(softnet_data.processed);
@@ -4346,15 +4349,14 @@ static int __init dev_proc_init(void)
 
 
 /**
- *	netdev_set_master	-	set up master/slave pair
+ *	netdev_set_master	-	set up master pointer
  *	@slave: slave device
  *	@master: new master device
  *
  *	Changes the master device of the slave. Pass %NULL to break the
  *	bonding. The caller must hold the RTNL semaphore. On a failure
  *	a negative errno code is returned. On success the reference counts
- *	are adjusted, %RTM_NEWLINK is sent to the routing socket and the
- *	function returns zero.
+ *	are adjusted and the function returns zero.
  */
 int netdev_set_master(struct net_device *slave, struct net_device *master)
 {
@@ -4374,6 +4376,29 @@ int netdev_set_master(struct net_device *slave, struct net_device *master)
 		synchronize_net();
 		dev_put(old);
 	}
+	return 0;
+}
+EXPORT_SYMBOL(netdev_set_master);
+
+/**
+ *	netdev_set_bond_master	-	set up bonding master/slave pair
+ *	@slave: slave device
+ *	@master: new master device
+ *
+ *	Changes the master device of the slave. Pass %NULL to break the
+ *	bonding. The caller must hold the RTNL semaphore. On a failure
+ *	a negative errno code is returned. On success %RTM_NEWLINK is sent
+ *	to the routing socket and the function returns zero.
+ */
+int netdev_set_bond_master(struct net_device *slave, struct net_device *master)
+{
+	int err;
+
+	ASSERT_RTNL();
+
+	err = netdev_set_master(slave, master);
+	if (err)
+		return err;
 	if (master)
 		slave->flags |= IFF_SLAVE;
 	else
@@ -4382,7 +4407,7 @@ int netdev_set_master(struct net_device *slave, struct net_device *master)
 	rtmsg_ifinfo(RTM_NEWLINK, slave, IFF_SLAVE);
 	return 0;
 }
-EXPORT_SYMBOL(netdev_set_master);
+EXPORT_SYMBOL(netdev_set_bond_master);
 
 static void dev_change_rx_flags(struct net_device *dev, int flags)
 {