geneve: only configure or fill UDP_ZERO_CSUM6_RX/TX info when CONFIG_IPV6

Stefano pointed that configure or show UDP_ZERO_CSUM6_RX/TX info doesn't
make sense if we haven't enabled CONFIG_IPV6. Fix it by adding
if IS_ENABLED(CONFIG_IPV6) check.

Fixes: abe492b4 ("geneve: UDP checksum configuration via netlink")
Fixes: fd7eafd0 ("geneve: fix fill_info when link down")
Signed-off-by: NHangbin Liu <liuhangbin@gmail.com>
Reviewed-by: NStefano Brivio <sbrivio@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/geneve.c

@@ -1337,21 +1337,33 @@ static int geneve_nl2info(struct nlattr *tb[], struct nlattr *data[],
 	}
 
 	if (data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX]) {
+#if IS_ENABLED(CONFIG_IPV6)
 		if (changelink) {
 			attrtype = IFLA_GENEVE_UDP_ZERO_CSUM6_TX;
 			goto change_notsup;
 		}
 		if (nla_get_u8(data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX]))
 			info->key.tun_flags &= ~TUNNEL_CSUM;
+#else
+		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX],
+				    "IPv6 support not enabled in the kernel");
+		return -EPFNOSUPPORT;
+#endif
 	}
 
 	if (data[IFLA_GENEVE_UDP_ZERO_CSUM6_RX]) {
+#if IS_ENABLED(CONFIG_IPV6)
 		if (changelink) {
 			attrtype = IFLA_GENEVE_UDP_ZERO_CSUM6_RX;
 			goto change_notsup;
 		}
 		if (nla_get_u8(data[IFLA_GENEVE_UDP_ZERO_CSUM6_RX]))
 			*use_udp6_rx_checksums = false;
+#else
+		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_UDP_ZERO_CSUM6_RX],
+				    "IPv6 support not enabled in the kernel");
+		return -EPFNOSUPPORT;
+#endif
 	}
 
 	return 0;
@@ -1529,9 +1541,11 @@ static int geneve_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	if (metadata && nla_put_flag(skb, IFLA_GENEVE_COLLECT_METADATA))
 		goto nla_put_failure;
 
+#if IS_ENABLED(CONFIG_IPV6)
 	if (nla_put_u8(skb, IFLA_GENEVE_UDP_ZERO_CSUM6_RX,
 		       !geneve->use_udp6_rx_checksums))
 		goto nla_put_failure;
+#endif
 
 	return 0;