[PATCH 4.16 026/161] net: ip6_gre: Split up ip6gre_newlink()

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Petr Machata <petrm@xxxxxxxxxxxx>

[ Upstream commit 7fa38a7c852ec99e3a7fc375eb2c21c50c2e46b8 ]

Extract from ip6gre_newlink() a reusable function
ip6gre_newlink_common(). The ip6gre_tnl_link_config() call needs to be
made customizable for ERSPAN, thus reorder it with calls to
ip6_tnl_change_mtu() and dev_hold(), and extract the whole tail to the
caller, ip6gre_newlink(). Thus enable an ERSPAN-specific _newlink()
function without a lot of duplicity.

Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support")
Signed-off-by: Petr Machata <petrm@xxxxxxxxxxxx>
Acked-by: William Tu <u9012063@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv6/ip6_gre.c |   24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1848,9 +1848,9 @@ static bool ip6gre_netlink_encap_parms(s
 	return ret;
 }
 
-static int ip6gre_newlink(struct net *src_net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
-			  struct netlink_ext_ack *extack)
+static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev,
+				 struct nlattr *tb[], struct nlattr *data[],
+				 struct netlink_ext_ack *extack)
 {
 	struct ip6_tnl *nt;
 	struct net *net = dev_net(dev);
@@ -1887,18 +1887,30 @@ static int ip6gre_newlink(struct net *sr
 	if (err)
 		goto out;
 
-	ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]);
-
 	if (tb[IFLA_MTU])
 		ip6_tnl_change_mtu(dev, nla_get_u32(tb[IFLA_MTU]));
 
 	dev_hold(dev);
-	ip6gre_tunnel_link(ign, nt);
 
 out:
 	return err;
 }
 
+static int ip6gre_newlink(struct net *src_net, struct net_device *dev,
+			  struct nlattr *tb[], struct nlattr *data[],
+			  struct netlink_ext_ack *extack)
+{
+	int err = ip6gre_newlink_common(src_net, dev, tb, data, extack);
+	struct ip6_tnl *nt = netdev_priv(dev);
+	struct net *net = dev_net(dev);
+
+	if (!err) {
+		ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]);
+		ip6gre_tunnel_link(net_generic(net, ip6gre_net_id), nt);
+	}
+	return err;
+}
+
 static int ip6gre_changelink(struct net_device *dev, struct nlattr *tb[],
 			     struct nlattr *data[],
 			     struct netlink_ext_ack *extack)