mlxsw: spectrum_router: Take router lock from netdev listener

One entry point into the routing code is from the netdev listener block.
Some netdev events require access to internal router structures. For
example, changing the MTU of a netdev requires looking-up the backing
RIF and adjusting its MTU.

In order to serialize access to shared router structures, take the
router lock when processing netdev events that require access to it.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -548,7 +548,7 @@ int mlxsw_sp_netdevice_vrf_event(struct net_device *l3_dev, unsigned long event,
 				 struct netdev_notifier_changeupper_info *info);
 bool mlxsw_sp_netdev_is_ipip_ol(const struct mlxsw_sp *mlxsw_sp,
 				const struct net_device *dev);
-bool mlxsw_sp_netdev_is_ipip_ul(const struct mlxsw_sp *mlxsw_sp,
+bool mlxsw_sp_netdev_is_ipip_ul(struct mlxsw_sp *mlxsw_sp,
 				const struct net_device *dev);
 int mlxsw_sp_netdevice_ipip_ol_event(struct mlxsw_sp *mlxsw_sp,
 				     struct net_device *l3_dev,

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -1346,10 +1346,16 @@ mlxsw_sp_ipip_entry_find_by_ul_dev(const struct mlxsw_sp *mlxsw_sp,
 	return NULL;
 }
 
-bool mlxsw_sp_netdev_is_ipip_ul(const struct mlxsw_sp *mlxsw_sp,
+bool mlxsw_sp_netdev_is_ipip_ul(struct mlxsw_sp *mlxsw_sp,
 				const struct net_device *dev)
 {
-	return mlxsw_sp_ipip_entry_find_by_ul_dev(mlxsw_sp, dev, NULL);
+	bool is_ipip_ul;
+
+	mutex_lock(&mlxsw_sp->router->lock);
+	is_ipip_ul = mlxsw_sp_ipip_entry_find_by_ul_dev(mlxsw_sp, dev, NULL);
+	mutex_unlock(&mlxsw_sp->router->lock);
+
+	return is_ipip_ul;
 }
 
 static bool mlxsw_sp_netdevice_ipip_can_offload(struct mlxsw_sp *mlxsw_sp,
@@ -1721,35 +1727,41 @@ int mlxsw_sp_netdevice_ipip_ol_event(struct mlxsw_sp *mlxsw_sp,
 {
 	struct netdev_notifier_changeupper_info *chup;
 	struct netlink_ext_ack *extack;
+	int err = 0;
 
+	mutex_lock(&mlxsw_sp->router->lock);
 	switch (event) {
 	case NETDEV_REGISTER:
-		return mlxsw_sp_netdevice_ipip_ol_reg_event(mlxsw_sp, ol_dev);
+		err = mlxsw_sp_netdevice_ipip_ol_reg_event(mlxsw_sp, ol_dev);
+		break;
 	case NETDEV_UNREGISTER:
 		mlxsw_sp_netdevice_ipip_ol_unreg_event(mlxsw_sp, ol_dev);
-		return 0;
+		break;
 	case NETDEV_UP:
 		mlxsw_sp_netdevice_ipip_ol_up_event(mlxsw_sp, ol_dev);
-		return 0;
+		break;
 	case NETDEV_DOWN:
 		mlxsw_sp_netdevice_ipip_ol_down_event(mlxsw_sp, ol_dev);
-		return 0;
+		break;
 	case NETDEV_CHANGEUPPER:
 		chup = container_of(info, typeof(*chup), info);
 		extack = info->extack;
 		if (netif_is_l3_master(chup->upper_dev))
-			return mlxsw_sp_netdevice_ipip_ol_vrf_event(mlxsw_sp,
-								    ol_dev,
-								    extack);
-		return 0;
+			err = mlxsw_sp_netdevice_ipip_ol_vrf_event(mlxsw_sp,
+								   ol_dev,
+								   extack);
+		break;
 	case NETDEV_CHANGE:
 		extack = info->extack;
-		return mlxsw_sp_netdevice_ipip_ol_change_event(mlxsw_sp,
-							       ol_dev, extack);
+		err = mlxsw_sp_netdevice_ipip_ol_change_event(mlxsw_sp,
+							      ol_dev, extack);
+		break;
 	case NETDEV_CHANGEMTU:
-		return mlxsw_sp_netdevice_ipip_ol_update_mtu(mlxsw_sp, ol_dev);
+		err = mlxsw_sp_netdevice_ipip_ol_update_mtu(mlxsw_sp, ol_dev);
+		break;
 	}
-	return 0;
+	mutex_unlock(&mlxsw_sp->router->lock);
+	return err;
 }
 
 static int
@@ -1793,8 +1805,9 @@ mlxsw_sp_netdevice_ipip_ul_event(struct mlxsw_sp *mlxsw_sp,
 				 struct netdev_notifier_info *info)
 {
 	struct mlxsw_sp_ipip_entry *ipip_entry = NULL;
-	int err;
+	int err = 0;
 
+	mutex_lock(&mlxsw_sp->router->lock);
 	while ((ipip_entry = mlxsw_sp_ipip_entry_find_by_ul_dev(mlxsw_sp,
 								ul_dev,
 								ipip_entry))) {
@@ -1807,7 +1820,7 @@ mlxsw_sp_netdevice_ipip_ul_event(struct mlxsw_sp *mlxsw_sp,
 		if (err) {
 			mlxsw_sp_ipip_demote_tunnel_by_ul_netdev(mlxsw_sp,
 								 ul_dev);
-			return err;
+			break;
 		}
 
 		if (demote_this) {
@@ -1824,8 +1837,9 @@ mlxsw_sp_netdevice_ipip_ul_event(struct mlxsw_sp *mlxsw_sp,
 			ipip_entry = prev;
 		}
 	}
+	mutex_unlock(&mlxsw_sp->router->lock);
 
-	return 0;
+	return err;
 }
 
 int mlxsw_sp_router_nve_promote_decap(struct mlxsw_sp *mlxsw_sp, u32 ul_tb_id,
@@ -7223,24 +7237,30 @@ int mlxsw_sp_netdevice_router_port_event(struct net_device *dev,
 {
 	struct mlxsw_sp *mlxsw_sp;
 	struct mlxsw_sp_rif *rif;
+	int err = 0;
 
 	mlxsw_sp = mlxsw_sp_lower_get(dev);
 	if (!mlxsw_sp)
 		return 0;
 
+	mutex_lock(&mlxsw_sp->router->lock);
 	rif = mlxsw_sp_rif_find_by_dev(mlxsw_sp, dev);
 	if (!rif)
-		return 0;
+		goto out;
 
 	switch (event) {
 	case NETDEV_CHANGEMTU: /* fall through */
 	case NETDEV_CHANGEADDR:
-		return mlxsw_sp_router_port_change_event(mlxsw_sp, rif);
+		err = mlxsw_sp_router_port_change_event(mlxsw_sp, rif);
+		break;
 	case NETDEV_PRE_CHANGEADDR:
-		return mlxsw_sp_router_port_pre_changeaddr_event(rif, ptr);
+		err = mlxsw_sp_router_port_pre_changeaddr_event(rif, ptr);
+		break;
 	}
 
-	return 0;
+out:
+	mutex_unlock(&mlxsw_sp->router->lock);
+	return err;
 }
 
 static int mlxsw_sp_port_vrf_join(struct mlxsw_sp *mlxsw_sp,
@@ -7283,9 +7303,10 @@ int mlxsw_sp_netdevice_vrf_event(struct net_device *l3_dev, unsigned long event,
 	if (!mlxsw_sp || netif_is_macvlan(l3_dev))
 		return 0;
 
+	mutex_lock(&mlxsw_sp->router->lock);
 	switch (event) {
 	case NETDEV_PRECHANGEUPPER:
-		return 0;
+		break;
 	case NETDEV_CHANGEUPPER:
 		if (info->linking) {
 			struct netlink_ext_ack *extack;
@@ -7297,6 +7318,7 @@ int mlxsw_sp_netdevice_vrf_event(struct net_device *l3_dev, unsigned long event,
 		}
 		break;
 	}
+	mutex_unlock(&mlxsw_sp->router->lock);
 
 	return err;
 }