bonding, net: Move last_rx update into bonding recv logic

The only user of the net_device->last_rx field is bonding.
This patch adds a conditional update of last_rx to the bonding special
logic in skb_bond_should_drop, causing last_rx to only be updated when
the ARP monitor is running.

	This frees network device drivers from the necessity of
updating last_rx, which can have cache line thrash issues.

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -4564,6 +4564,8 @@ static int bond_init(struct net_device *bond_dev, struct bond_params *params)
 	bond_dev->tx_queue_len = 0;
 	bond_dev->flags |= IFF_MASTER|IFF_MULTICAST;
 	bond_dev->priv_flags |= IFF_BONDING;
+	if (bond->params.arp_interval)
+		bond_dev->priv_flags |= IFF_MASTER_ARPMON;
 
 	/* At first, we block adding VLANs. That's the only way to
 	 * prevent problems that occur when adding VLANs over an

drivers/net/bonding/bond_sysfs.c

@@ -620,6 +620,8 @@ static ssize_t bonding_store_arp_interval(struct device *d,
 	       ": %s: Setting ARP monitoring interval to %d.\n",
 	       bond->dev->name, new_value);
 	bond->params.arp_interval = new_value;
+	if (bond->params.arp_interval)
+		bond->dev->priv_flags |= IFF_MASTER_ARPMON;
 	if (bond->params.miimon) {
 		printk(KERN_INFO DRV_NAME
 		       ": %s: ARP monitoring cannot be used with MII monitoring. "
@@ -1039,6 +1041,7 @@ static ssize_t bonding_store_miimon(struct device *d,
 			       "ARP monitoring. Disabling ARP monitoring...\n",
 			       bond->dev->name);
 			bond->params.arp_interval = 0;
+			bond->dev->priv_flags &= ~IFF_MASTER_ARPMON;
 			if (bond->params.arp_validate) {
 				bond_unregister_arp(bond);
 				bond->params.arp_validate =