[ARP]: Introduce the arp_hdr_len helper.

There are some place, that calculate the ARP header length. These
calculations are correct, but 
 a) some operate with "magic" constants,
 b) enlarge the code length (sometimes at the cost of coding style),
 c) are not informative from the first glance.

The proposal is to introduce a helper, that includes all the good
sides of these calculations.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 4 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 966643473da7..5fc9d8d58ece 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2646,10 +2646,7 @@ static int bond_arp_rcv(struct sk_buff *skb, struct net_device *dev, struct pack
         if (!slave || !slave_do_arp_validate(bond, slave))
                 goto out_unlock;
 
-        /* ARP header, plus 2 device addresses, plus 2 IP addresses.  */
-        if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
-                                 (2 * dev->addr_len) +
-                                 (2 * sizeof(u32)))))
+        if (!pskb_may_pull(skb, arp_hdr_len(dev)))
                 goto out_unlock;
 
         arp = arp_hdr(skb);