openvswitch: return NF_ACCEPT when OVS_CT_NAT is not set in info nat

Either OVS_CT_SRC_NAT or OVS_CT_DST_NAT is set, OVS_CT_NAT must be
set in info->nat. Thus, if OVS_CT_NAT is not set in info->nat, it
will definitely not do NAT but returns NF_ACCEPT in ovs_ct_nat().

This patch changes nothing funcational but only makes this return
earlier in ovs_ct_nat() to keep consistent with TC's processing
in tcf_ct_act_nat().

Reviewed-by: Saeed Mahameed <saeed@kernel.org>
Acked-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/openvswitch/conntrack.c

@@ -816,6 +816,9 @@ static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
 	enum nf_nat_manip_type maniptype;
 	int err;
 
+	if (!(info->nat & OVS_CT_NAT))
+		return NF_ACCEPT;
+
 	/* Add NAT extension if not confirmed yet. */
 	if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct))
 		return NF_ACCEPT;   /* Can't NAT. */
@@ -825,8 +828,7 @@ static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
 	 * Make sure new expected connections (IP_CT_RELATED) are NATted only
 	 * when committing.
 	 */
-	if (info->nat & OVS_CT_NAT && ctinfo != IP_CT_NEW &&
-	    ct->status & IPS_NAT_MASK &&
+	if (ctinfo != IP_CT_NEW && ct->status & IPS_NAT_MASK &&
 	    (ctinfo != IP_CT_RELATED || info->commit)) {
 		/* NAT an established or related connection like before. */
 		if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY)