[PATCH net 3/3] mlxsw: spectrum_router: Handle MTU change of GRE netdevs

[Ido Schimmel]

From: Petr Machata <pe...@mellanox.com>

Update MTU of overlay loopback in accordance with the setting on the
tunnel netdevice.

Fixes: 0063587d3587 ("mlxsw: spectrum: Support decap-only IP-in-IP tunnels")
Signed-off-by: Petr Machata <pe...@mellanox.com>
Signed-off-by: Ido Schimmel <ido...@mellanox.com>
---
 .../net/ethernet/mellanox/mlxsw/spectrum_router.c  | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c 
b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index a7d0adf068ec..997e24dcb053 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -1407,6 +1407,28 @@ mlxsw_sp_rif_ipip_lb_op(struct mlxsw_sp_rif_ipip_lb 
*lb_rif,
        return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ritr), ritr_pl);
 }
 
+static int mlxsw_sp_netdevice_ipip_ol_update_mtu(struct mlxsw_sp *mlxsw_sp,
+                                                struct net_device *ol_dev)
+{
+       struct mlxsw_sp_ipip_entry *ipip_entry;
+       struct mlxsw_sp_rif_ipip_lb *lb_rif;
+       struct mlxsw_sp_vr *ul_vr;
+       int err = 0;
+
+       ipip_entry = mlxsw_sp_ipip_entry_find_by_ol_dev(mlxsw_sp, ol_dev);
+       if (ipip_entry) {
+               lb_rif = ipip_entry->ol_lb;
+               ul_vr = &mlxsw_sp->router->vrs[lb_rif->ul_vr_id];
+               err = mlxsw_sp_rif_ipip_lb_op(lb_rif, ul_vr, true);
+               if (err)
+                       goto out;
+               lb_rif->common.mtu = ol_dev->mtu;
+       }
+
+out:
+       return err;
+}
+
 static void mlxsw_sp_netdevice_ipip_ol_up_event(struct mlxsw_sp *mlxsw_sp,
                                                struct net_device *ol_dev)
 {
@@ -1687,6 +1709,8 @@ int mlxsw_sp_netdevice_ipip_ol_event(struct mlxsw_sp 
*mlxsw_sp,
                extack = info->extack;
                return mlxsw_sp_netdevice_ipip_ol_change_event(mlxsw_sp,
                                                               ol_dev, extack);
+       case NETDEV_CHANGEMTU:
+               return mlxsw_sp_netdevice_ipip_ol_update_mtu(mlxsw_sp, ol_dev);
        }
        return 0;
 }
-- 
2.14.3