bonding: don't validate arp if we don't have to

Currently, we validate all the incoming arps if arp_validate not 0.
However, we don't have to validate backup slaves if arp_validate == active
and vice versa, so return early in bond_arp_rcv() in these cases.

It works correctly now because we verify arp_validate in slave_last_rx(),
however we're just doing useless work in bond_arp_rcv().
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -2634,6 +2634,10 @@ static int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond,
 		return RX_HANDLER_ANOTHER;
 
 	read_lock(&bond->lock);
+
+	if (!slave_do_arp_validate(bond, slave))
+		goto out_unlock;
+
 	alen = arp_hdr_len(bond->dev);
 
 	pr_debug("bond_arp_rcv: bond %s skb->dev %s\n",