[SRU][PATCH 1/1] geneve: correctly handle ipv6.disable module parameter

[Nivedita Singhvi]

From: Jiri Benc <jbenc at redhat.com>

BugLink: https://bugs.launchpad.net/bugs/1794232

When IPv6 is compiled but disabled at runtime, geneve_sock_add 
returns -EAFNOSUPPORT. For metadata based tunnels, this causes 
failure of the whole operation of bringing up the tunnel.

Ignore failure of IPv6 socket creation for metadata based tunnels 
caused by IPv6 not being available.

This is the same fix as what commit d074bf960044 ("vxlan: correctly 
handle ipv6.disable module parameter") is doing for vxlan.

Note there's also commit c0a47e44c098 ("geneve: should not call 
rt6_lookup() when ipv6 was disabled") which fixes a similar issue 
but for regular tunnels, while this patch is needed for metadata 
based tunnels.

Signed-off-by: Jiri Benc <jbenc at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(backported from commit cf1c9ccba7308e48a68fa77f476287d9d614e4c7)
[ niv: infra.mode omitted and remote.sa.sa_family == AF_INET6
  check retained to avoid pulling in lot of new infrastructure ]
Signed-off-by: Nivedita Singhvi <nivedita.singhvi at canonical.com>
---
 drivers/net/geneve.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 1a7acf6a6455..df2ae135da1c 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -627,15 +627,19 @@ static int geneve_open(struct net_device *dev)
 	struct geneve_dev *geneve = netdev_priv(dev);
 	bool ipv6 = geneve->remote.sa.sa_family == AF_INET6;
 	bool metadata = geneve->collect_md;
+	bool ipv4 = !ipv6 || metadata;
 	int ret = 0;
 
 	geneve->sock4 = NULL;
 #if IS_ENABLED(CONFIG_IPV6)
 	geneve->sock6 = NULL;
-	if (ipv6 || metadata)
+	if (ipv6) {
 		ret = geneve_sock_add(geneve, true);
+		if (ret < 0 && ret != -EAFNOSUPPORT)
+			ipv4 = false;
+	}
 #endif
-	if (!ret && (!ipv6 || metadata))
+	if (ipv4)
 		ret = geneve_sock_add(geneve, false);
 	if (ret < 0)
 		geneve_sock_release(geneve);
-- 
2.17.1