mlxsw: spectrum: Support decap-only IP-in-IP tunnels

Current code for offloading IP-in-IP tunneling assumes that there is no
decap without encap. But that's never true for IPv6 overlays, and is not
true for IPv4 ones either, if net.ipv4.conf.*.rp_filter is unset.

To support decap-only tunnels, an IPIP entry is now created as soon as
an offloadable tunneling device is created. When that netdevice is up'd,
a decap route is looked up and possibly offloaded. Thus decap is not
handled implicitly as part of mlxsw_sp_ipip_entry_get() call anymore,
but needs to be done explicitly after the get, if desired.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 83f9c25..c3ae650 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -4497,13 +4497,17 @@ static bool mlxsw_sp_is_vrf_event(unsigned long event, void *ptr)
 	return netif_is_l3_master(info->upper_dev);
 }
 
-static int mlxsw_sp_netdevice_event(struct notifier_block *unused,
+static int mlxsw_sp_netdevice_event(struct notifier_block *nb,
 				    unsigned long event, void *ptr)
 {
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct mlxsw_sp *mlxsw_sp;
 	int err = 0;
 
-	if (event == NETDEV_CHANGEADDR || event == NETDEV_CHANGEMTU)
+	mlxsw_sp = container_of(nb, struct mlxsw_sp, netdevice_nb);
+	if (mlxsw_sp_netdev_is_ipip(mlxsw_sp, dev))
+		err = mlxsw_sp_netdevice_ipip_event(mlxsw_sp, dev, event);
+	else if (event == NETDEV_CHANGEADDR || event == NETDEV_CHANGEMTU)
 		err = mlxsw_sp_netdevice_router_port_event(dev);
 	else if (mlxsw_sp_is_vrf_event(event, ptr))
 		err = mlxsw_sp_netdevice_vrf_event(dev, event, ptr);