net: Swap ordering of tests in ip_route_input_mc

This patch just swaps the ordering of one of the conditional tests in
ip_route_input_mc.  Specifically it swaps the testing for the source
address to see if it is loopback, and the test to see if we allow a
loopback source address.

The reason for swapping these two tests is because it is much faster to
test if an address is loopback than it is to dereference several pointers
to get at the net structure to see if the use of loopback is allowed.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 6bab84503cd9bb9622a3f269e7cde67aafc9b6aa..43508c8d08e28f7db3681b610bf770903797484a 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1487,9 +1487,8 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
            skb->protocol != htons(ETH_P_IP))
                goto e_inval;
 
-       if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
-               if (ipv4_is_loopback(saddr))
-                       goto e_inval;
+       if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
+               goto e_inval;
 
        if (ipv4_is_zeronet(saddr)) {
                if (!ipv4_is_local_multicast(daddr))