[IPV4]: Avoid common branch mispredictions in ip_rcv_finish()

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 48e4ddc1e33744c27ae38e60e8acf31bc453e85f..7e78095baef1a73fa240132a51276332f0e93c98 100644 (file)
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -333,16 +333,16 @@ drop:
 
 static inline int ip_rcv_finish(struct sk_buff *skb)
 {
-       struct net_device *dev = skb->dev;
        struct iphdr *iph = skb->nh.iph;
-       int err;
 
        /*
         *      Initialise the virtual path cache for the packet. It describes
         *      how the packet travels inside Linux networking.
         */ 
-       if (skb->dst == NULL) {
-               if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
+       if (likely(skb->dst == NULL)) {
+               int err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
+                                        skb->dev);
+               if (unlikely(err)) {
                        if (err == -EHOSTUNREACH)
                                IP_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS);
                        goto drop; 
@@ -350,7 +350,7 @@ static inline int ip_rcv_finish(struct sk_buff *skb)
        }
 
 #ifdef CONFIG_NET_CLS_ROUTE
-       if (skb->dst->tclassid) {
+       if (unlikely(skb->dst->tclassid)) {
                struct ip_rt_acct *st = ip_rt_acct + 256*smp_processor_id();
                u32 idx = skb->dst->tclassid;
                st[idx&0xFF].o_packets++;