inet: Don't lookup the socket if there's a socket attached to the skb

Use the socket cached in the skb if it's present.

Signed-off-by: KOVACS Krisztian <hidden@sch.bme.hu>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index 995efbb..f74665d 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h
@@ -96,10 +96,14 @@
 					      const __be16 sport,
 					      const __be16 dport)
 {
-	return __inet6_lookup(dev_net(skb->dst->dev), hashinfo,
-			      &ipv6_hdr(skb)->saddr, sport,
-			      &ipv6_hdr(skb)->daddr, ntohs(dport),
-			      inet6_iif(skb));
+	struct sock *sk;
+
+	if (unlikely(sk = skb_steal_sock(skb)))
+		return sk;
+	else return __inet6_lookup(dev_net(skb->dst->dev), hashinfo,
+				   &ipv6_hdr(skb)->saddr, sport,
+				   &ipv6_hdr(skb)->daddr, ntohs(dport),
+				   inet6_iif(skb));
 }
 
 extern struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,