mlxsw: spectrum_switchdev: Manage RIFs on PVID change

Currently, mlxsw has several shortcomings with regards to RIF handling due
to PVID changes:

- In order to cause RIF for a bridge device to be created, the user is
  expected first to set PVID, then to add an IP address. The reverse
  ordering is disallowed, which is not very user-friendly.

- When such bridge gets a VLAN upper whose VID was the same as the existing
  PVID, and this VLAN netdevice gets an IP address, a RIF is created for
  this netdevice. The new RIF is then assigned to the 802.1Q FID for the
  given VID. This results in a working configuration. However, then, when
  the VLAN netdevice is removed again, the RIF for the bridge itself is
  never reassociated to the VLAN.

- PVID cannot be changed once the bridge has uppers. Presumably this is
  because the driver does not manage RIFs properly in face of PVID changes.
  However, as the previous point shows, it is still possible to get into
  invalid configurations.

In this patch, add the logic necessary for creation of a RIF as a result of
PVID change. Moreover, when a VLAN upper is created whose VID matches lower
PVID, do not create RIF for this netdevice.

These changes obviate the need for ordering of IP address additions and
PVID configuration, so stop forbidding addition of an IP address to a
PVID-less bridge. Instead, bail out quietly. Also stop preventing PVID
changes when the bridge has uppers.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -8411,6 +8411,110 @@ void mlxsw_sp_rif_destroy_by_dev(struct mlxsw_sp *mlxsw_sp,
 	mutex_unlock(&mlxsw_sp->router->lock);
 }
 
+static void mlxsw_sp_rif_destroy_vlan_upper(struct mlxsw_sp *mlxsw_sp,
+					    struct net_device *br_dev,
+					    u16 vid)
+{
+	struct net_device *upper_dev;
+	struct mlxsw_sp_crif *crif;
+
+	rcu_read_lock();
+	upper_dev = __vlan_find_dev_deep_rcu(br_dev, htons(ETH_P_8021Q), vid);
+	rcu_read_unlock();
+
+	if (!upper_dev)
+		return;
+
+	crif = mlxsw_sp_crif_lookup(mlxsw_sp->router, upper_dev);
+	if (!crif || !crif->rif)
+		return;
+
+	mlxsw_sp_rif_destroy(crif->rif);
+}
+
+static int mlxsw_sp_inetaddr_bridge_event(struct mlxsw_sp *mlxsw_sp,
+					  struct net_device *l3_dev,
+					  int lower_pvid,
+					  unsigned long event,
+					  struct netlink_ext_ack *extack);
+
+int mlxsw_sp_router_bridge_vlan_add(struct mlxsw_sp *mlxsw_sp,
+				    struct net_device *br_dev,
+				    u16 new_vid, bool is_pvid,
+				    struct netlink_ext_ack *extack)
+{
+	struct mlxsw_sp_rif *old_rif;
+	struct mlxsw_sp_rif *new_rif;
+	struct net_device *upper_dev;
+	u16 old_pvid = 0;
+	u16 new_pvid;
+	int err = 0;
+
+	mutex_lock(&mlxsw_sp->router->lock);
+	old_rif = mlxsw_sp_rif_find_by_dev(mlxsw_sp, br_dev);
+	if (old_rif) {
+		/* If the RIF on the bridge is not a VLAN RIF, we shouldn't have
+		 * gotten a PVID notification.
+		 */
+		if (WARN_ON(old_rif->ops->type != MLXSW_SP_RIF_TYPE_VLAN))
+			old_rif = NULL;
+		else
+			old_pvid = mlxsw_sp_fid_8021q_vid(old_rif->fid);
+	}
+
+	if (is_pvid)
+		new_pvid = new_vid;
+	else if (old_pvid == new_vid)
+		new_pvid = 0;
+	else
+		goto out;
+
+	if (old_pvid == new_pvid)
+		goto out;
+
+	if (new_pvid) {
+		struct mlxsw_sp_rif_params params = {
+			.dev = br_dev,
+			.vid = new_pvid,
+		};
+
+		/* If there is a VLAN upper with the same VID as the new PVID,
+		 * kill its RIF, if there is one.
+		 */
+		mlxsw_sp_rif_destroy_vlan_upper(mlxsw_sp, br_dev, new_pvid);
+
+		if (mlxsw_sp_dev_addr_list_empty(br_dev))
+			goto out;
+		new_rif = mlxsw_sp_rif_create(mlxsw_sp, &params, extack);
+		if (IS_ERR(new_rif)) {
+			err = PTR_ERR(new_rif);
+			goto out;
+		}
+
+		if (old_pvid)
+			mlxsw_sp_rif_migrate_destroy(mlxsw_sp, old_rif, new_rif,
+						     true);
+	} else {
+		mlxsw_sp_rif_destroy(old_rif);
+	}
+
+	if (old_pvid) {
+		rcu_read_lock();
+		upper_dev = __vlan_find_dev_deep_rcu(br_dev, htons(ETH_P_8021Q),
+						     old_pvid);
+		rcu_read_unlock();
+		if (upper_dev)
+			err = mlxsw_sp_inetaddr_bridge_event(mlxsw_sp,
+							     upper_dev,
+							     new_pvid,
+							     NETDEV_UP, extack);
+	}
+
+out:
+	mutex_unlock(&mlxsw_sp->router->lock);
+	return err;
+}
+
 static void
 mlxsw_sp_rif_subport_params_init(struct mlxsw_sp_rif_params *params,
 				 struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan)
@@ -8847,13 +8951,20 @@ static int mlxsw_sp_inetaddr_bridge_event(struct mlxsw_sp *mlxsw_sp,
 				return -EOPNOTSUPP;
 			}
 			err = br_vlan_get_pvid(l3_dev, &params.vid);
-			if (err < 0 || !params.vid) {
-				NL_SET_ERR_MSG_MOD(extack, "Couldn't determine bridge PVID");
-				return -EINVAL;
-			}
+			if (err)
+				return err;
+			if (!params.vid)
+				return 0;
 		} else if (is_vlan_dev(l3_dev)) {
 			params.vid = vlan_dev_vlan_id(l3_dev);
+
+			/* If the VID matches PVID of the bridge below, the
+			 * bridge owns the RIF for this VLAN. Don't do anything.
+			 */
+			if ((int)params.vid == lower_pvid)
+				return 0;
 		}
+
 		rif = mlxsw_sp_rif_create(mlxsw_sp, &params, extack);
 		if (IS_ERR(rif))
 			return PTR_ERR(rif);

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

@@ -171,6 +171,10 @@ int mlxsw_sp_ipip_ecn_encap_init(struct mlxsw_sp *mlxsw_sp);
 int mlxsw_sp_ipip_ecn_decap_init(struct mlxsw_sp *mlxsw_sp);
 struct net_device *
 mlxsw_sp_ipip_netdev_ul_dev_get(const struct net_device *ol_dev);
+int mlxsw_sp_router_bridge_vlan_add(struct mlxsw_sp *mlxsw_sp,
+				    struct net_device *dev,
+				    u16 new_vid, bool is_pvid,
+				    struct netlink_ext_ack *extack);
 int mlxsw_sp_router_port_join_lag(struct mlxsw_sp_port *mlxsw_sp_port,
 				  struct net_device *lag_dev,
 				  struct netlink_ext_ack *extack);

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

@@ -1479,30 +1479,15 @@ mlxsw_sp_bridge_port_vlan_add(struct mlxsw_sp_port *mlxsw_sp_port,
 }
 
 static int
-mlxsw_sp_br_ban_rif_pvid_change(struct mlxsw_sp *mlxsw_sp,
-				const struct net_device *br_dev,
-				const struct switchdev_obj_port_vlan *vlan,
-				struct netlink_ext_ack *extack)
+mlxsw_sp_br_rif_pvid_change(struct mlxsw_sp *mlxsw_sp,
+			    struct net_device *br_dev,
+			    const struct switchdev_obj_port_vlan *vlan,
+			    struct netlink_ext_ack *extack)
 {
-	u16 pvid;
-
-	pvid = mlxsw_sp_rif_vid(mlxsw_sp, br_dev);
-	if (!pvid)
-		return 0;
-
-	if (vlan->flags & BRIDGE_VLAN_INFO_PVID) {
-		if (vlan->vid != pvid) {
-			NL_SET_ERR_MSG_MOD(extack, "Can't change PVID, it's used by router interface");
-			return -EBUSY;
-		}
-	} else {
-		if (vlan->vid == pvid) {
-			NL_SET_ERR_MSG_MOD(extack, "Can't remove PVID, it's used by router interface");
-			return -EBUSY;
-		}
-	}
+	bool flag_pvid = vlan->flags & BRIDGE_VLAN_INFO_PVID;
 
-	return 0;
+	return mlxsw_sp_router_bridge_vlan_add(mlxsw_sp, br_dev, vlan->vid,
+					       flag_pvid, extack);
 }
 
 static int mlxsw_sp_port_vlans_add(struct mlxsw_sp_port *mlxsw_sp_port,
@@ -1519,9 +1504,8 @@ static int mlxsw_sp_port_vlans_add(struct mlxsw_sp_port *mlxsw_sp_port,
 		int err = 0;
 
 		if (br_vlan_enabled(orig_dev))
-			err = mlxsw_sp_br_ban_rif_pvid_change(mlxsw_sp,
-							      orig_dev, vlan,
-							      extack);
+			err = mlxsw_sp_br_rif_pvid_change(mlxsw_sp, orig_dev,
+							  vlan, extack);
 		if (!err)
 			err = -EOPNOTSUPP;
 		return err;