[PATCH net-next v2] tipc: fix undefined __ipv6_sock_mc_join compile error

[Ying Xue <ying.xue@windriver.com>]

When CONFIG_IPV6 option is disabled, below error will appear while
building TIPC module:

ERROR: "__ipv6_sock_mc_join" [net/tipc/tipc.ko] undefined!
make[1]: *** [__modpost] Error 1
make: *** [net/tipc/tipc.ko] Error 1

This is because we don't check whether or not the CONFIG_IPV6 is
enabled when calling __ipv6_sock_mc_join().

In addition, especially when TIPC=y, TIPC_MEDIA_UDP=y, and IPV6=m, TIPC
module is also unable to be successfully built. Therefore, we add a
dependency condition like (IPV6 || IPV6=n) to avoid the error.

Fixes: d0f91938bede ("tipc: add ip/udp media type")
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Kbuild test robot <kbuild-all@01.org>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
---
v2:
 Fix another compile error when TIPC=y, TIPC_MEDIA_UDP=y, and IPV6=m

 net/tipc/Kconfig     |    1 +
 net/tipc/udp_media.c |    2 ++
 2 files changed, 3 insertions(+)

diff --git a/net/tipc/Kconfig b/net/tipc/Kconfig
index c25a3a1..6f217ba 100644
--- a/net/tipc/Kconfig
+++ b/net/tipc/Kconfig
@@ -5,6 +5,7 @@
 menuconfig TIPC
 	tristate "The TIPC Protocol"
 	depends on INET
+	depends on (IPV6 || IPV6=n)
 	---help---
 	  The Transparent Inter Process Communication (TIPC) protocol is
 	  specially designed for intra cluster communication. This protocol
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index fc2fb11..6763002 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -247,10 +247,12 @@ static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
 		mreqn.imr_multiaddr = remote->ipv4;
 		mreqn.imr_ifindex = ub->ifindex;
 		err = __ip_mc_join_group(sk, &mreqn);
+#if IS_ENABLED(CONFIG_IPV6)
 	} else {
 		if (!ipv6_addr_is_multicast(&remote->ipv6))
 			return 0;
 		err = __ipv6_sock_mc_join(sk, ub->ifindex, &remote->ipv6);
+#endif
 	}
 	return err;
 }
-- 
1.7.9.5


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