[PATCH v2] ip_tunnel: enclose a code block in macro IS_ENABLED(CONFIG_IPV6)

[Haishuang Yan]

For ipv6 case, enclose the code block in macro IS_ENABLED(CONFIG_IPV6).

---
Changes in v2:
  - Place the "#if IS_ENABLED" block before the "} else if
(..) {" piece and the "#endif" before the closing brace and this
becomes much easier to look at.

Signed-off-by: Haishuang Yan <yanhaishu...@cmss.chinamobile.com>
---
 net/ipv4/ip_tunnel.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index a69ed94..4256349 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -665,9 +665,11 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device 
*dev,
                if (skb->protocol == htons(ETH_P_IP)) {
                        tos = inner_iph->tos;
                        connected = false;
+#if IS_ENABLED(CONFIG_IPV6)
                } else if (skb->protocol == htons(ETH_P_IPV6)) {
                        tos = ipv6_get_dsfield((const struct ipv6hdr 
*)inner_iph);
                        connected = false;
+#endif
                }
        }
 
-- 
1.8.3.1