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>

1 files changed, 37 insertions, 12 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index d874fd1baf49..a4132766d363 100644
--- a/net/core/dev.c
+++ b/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)
 {