net: ip6_gre: Split up ip6gre_changelink()

BugLink: http://bugs.launchpad.net/bugs/1783418
[ Upstream commit c8632fc30bb03aa0c3bd7bcce85355a10feb8149 ]

Extract from ip6gre_changelink() a reusable function
ip6gre_changelink_common(). This will allow introduction of
ERSPAN-specific _changelink() function with not a lot of code
duplication.

Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support")
Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 0973c358f0eeae47f59a6505c34a6d16bfb7f7db..14f66046bd72edf95ce9cf5a7d6d89279c623afc 100644 (file)
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1457,37 +1457,52 @@ static int ip6gre_newlink(struct net *src_net, struct net_device *dev,
        return err;
 }
 
-static int ip6gre_changelink(struct net_device *dev, struct nlattr *tb[],
-                            struct nlattr *data[],
-                            struct netlink_ext_ack *extack)
+static struct ip6_tnl *
+ip6gre_changelink_common(struct net_device *dev, struct nlattr *tb[],
+                        struct nlattr *data[], struct __ip6_tnl_parm *p_p,
+                        struct netlink_ext_ack *extack)
 {
        struct ip6_tnl *t, *nt = netdev_priv(dev);
        struct net *net = nt->net;
        struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
-       struct __ip6_tnl_parm p;
        struct ip_tunnel_encap ipencap;
 
        if (dev == ign->fb_tunnel_dev)
-               return -EINVAL;
+               return ERR_PTR(-EINVAL);
 
        if (ip6gre_netlink_encap_parms(data, &ipencap)) {
                int err = ip6_tnl_encap_setup(nt, &ipencap);
 
                if (err < 0)
-                       return err;
+                       return ERR_PTR(err);
        }
 
-       ip6gre_netlink_parms(data, &p);
+       ip6gre_netlink_parms(data, p_p);
 
-       t = ip6gre_tunnel_locate(net, &p, 0);
+       t = ip6gre_tunnel_locate(net, p_p, 0);
 
        if (t) {
                if (t->dev != dev)
-                       return -EEXIST;
+                       return ERR_PTR(-EEXIST);
        } else {
                t = nt;
        }
 
+       return t;
+}
+
+static int ip6gre_changelink(struct net_device *dev, struct nlattr *tb[],
+                            struct nlattr *data[],
+                            struct netlink_ext_ack *extack)
+{
+       struct ip6gre_net *ign = net_generic(dev_net(dev), ip6gre_net_id);
+       struct __ip6_tnl_parm p;
+       struct ip6_tnl *t;
+
+       t = ip6gre_changelink_common(dev, tb, data, &p, extack);
+       if (IS_ERR(t))
+               return PTR_ERR(t);
+
        ip6gre_tunnel_unlink(ign, t);
        ip6gre_tnl_change(t, &p, !tb[IFLA_MTU]);
        ip6gre_tunnel_link(ign, t);