ipvs: avoid lookup for fwmark 0

 	Restore the previous behaviour to lookup for fwmark
service only when fwmark is non-null. This saves only CPU.
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NHans Schillstrom <hans@schillstrom.com>
Signed-off-by: NSimon Horman <horms@verge.net.au>

net/netfilter/ipvs/ip_vs_ctl.c

@@ -411,9 +411,11 @@ ip_vs_service_get(struct net *net, int af, __u32 fwmark, __u16 protocol,
 	/*
 	 *	Check the table hashed by fwmark first
 	 */
-	svc = __ip_vs_svc_fwm_find(net, af, fwmark);
-	if (fwmark && svc)
-		goto out;
+	if (fwmark) {
+		svc = __ip_vs_svc_fwm_find(net, af, fwmark);
+		if (svc)
+			goto out;
+	}
 
 	/*
 	 *	Check the table hashed by <protocol,addr,port>