[NETFILTER]: nf_conntrack: use jhash2 in __hash_conntrack

Now it uses jhash, but using jhash2 would be around 3-4 times faster
(on P4).
Signed-off-by: Sami Farin <safari-netfilter@safari.iki.fi>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter/nf_conntrack_core.c

@@ -128,10 +128,11 @@ static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 				  unsigned int size, unsigned int rnd)
 {
 	unsigned int a, b;
-	a = jhash((void *)tuple->src.u3.all, sizeof(tuple->src.u3.all),
-		  ((tuple->src.l3num) << 16) | tuple->dst.protonum);
-	b = jhash((void *)tuple->dst.u3.all, sizeof(tuple->dst.u3.all),
-			(tuple->src.u.all << 16) | tuple->dst.u.all);
+
+	a = jhash2(tuple->src.u3.all, ARRAY_SIZE(tuple->src.u3.all),
+		   (tuple->src.l3num << 16) | tuple->dst.protonum);
+	b = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),
+		   (tuple->src.u.all << 16) | tuple->dst.u.all);
 
 	return jhash_2words(a, b, rnd) % size;
 }