mlxsw: spectrum: Flush FDB when leaving bridge

As explained in previous commit, we should always take care of flushing
the FDB in the driver and not rely on bridge code.

We need to distinguish between two cases with regards to LAG:

1) Port is leaving LAG while LAG is bridged (or VLAN devices on top of
it). In this case don't flush the FDB entries pointing to the LAG ID, as
this will affect other ports still member in the LAG. Only flush the FDB
when the last port in the LAG is leaving the bridge.

2) LAG device is leaving the bridge. In this case the CHANGEUPPER event
is simply propagated to each member port, so make each port flush the
FDB in its turn.

Note that emptying a bridged LAG from ports creates an inconsistency
between hardware and software. A user who later (< ageing_time)
re-populates the LAG won't have any FDB entries pointing to the LAG ID
in hardware, but they will be present in the software bridge's FDB.
Currently there is no good solution to this problem, but this will be
addressed by us in the future.

In order to optimize the flushing process, flush by port or LAG ID if
there are no VLAN interfaces on top of the port. Otherwise, flush using
(Port / LAG ID, FID=VID} for each of the lower 4K FIDs. In the case of
VLAN device simply flush using {Port / LAG ID, vFID} with the vFID to
which the VLAN device is mapped to.

Fixes: 56ade8fe ("mlxsw: spectrum: Add initial support for Spectrum ASIC")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1979,6 +1979,115 @@ static struct mlxsw_driver mlxsw_sp_driver = {
 	.profile		= &mlxsw_sp_config_profile,
 };
 
+static int
+mlxsw_sp_port_fdb_flush_by_port(const struct mlxsw_sp_port *mlxsw_sp_port)
+{
+	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+	char sfdf_pl[MLXSW_REG_SFDF_LEN];
+
+	mlxsw_reg_sfdf_pack(sfdf_pl, MLXSW_REG_SFDF_FLUSH_PER_PORT);
+	mlxsw_reg_sfdf_system_port_set(sfdf_pl, mlxsw_sp_port->local_port);
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(sfdf), sfdf_pl);
+}
+
+static int
+mlxsw_sp_port_fdb_flush_by_port_fid(const struct mlxsw_sp_port *mlxsw_sp_port,
+				    u16 fid)
+{
+	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+	char sfdf_pl[MLXSW_REG_SFDF_LEN];
+
+	mlxsw_reg_sfdf_pack(sfdf_pl, MLXSW_REG_SFDF_FLUSH_PER_PORT_AND_FID);
+	mlxsw_reg_sfdf_fid_set(sfdf_pl, fid);
+	mlxsw_reg_sfdf_port_fid_system_port_set(sfdf_pl,
+						mlxsw_sp_port->local_port);
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(sfdf), sfdf_pl);
+}
+
+static int
+mlxsw_sp_port_fdb_flush_by_lag_id(const struct mlxsw_sp_port *mlxsw_sp_port)
+{
+	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+	char sfdf_pl[MLXSW_REG_SFDF_LEN];
+
+	mlxsw_reg_sfdf_pack(sfdf_pl, MLXSW_REG_SFDF_FLUSH_PER_LAG);
+	mlxsw_reg_sfdf_lag_id_set(sfdf_pl, mlxsw_sp_port->lag_id);
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(sfdf), sfdf_pl);
+}
+
+static int
+mlxsw_sp_port_fdb_flush_by_lag_id_fid(const struct mlxsw_sp_port *mlxsw_sp_port,
+				      u16 fid)
+{
+	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+	char sfdf_pl[MLXSW_REG_SFDF_LEN];
+
+	mlxsw_reg_sfdf_pack(sfdf_pl, MLXSW_REG_SFDF_FLUSH_PER_LAG_AND_FID);
+	mlxsw_reg_sfdf_fid_set(sfdf_pl, fid);
+	mlxsw_reg_sfdf_lag_fid_lag_id_set(sfdf_pl, mlxsw_sp_port->lag_id);
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(sfdf), sfdf_pl);
+}
+
+static int
+__mlxsw_sp_port_fdb_flush(const struct mlxsw_sp_port *mlxsw_sp_port)
+{
+	int err, last_err = 0;
+	u16 vid;
+
+	for (vid = 1; vid < VLAN_N_VID - 1; vid++) {
+		err = mlxsw_sp_port_fdb_flush_by_port_fid(mlxsw_sp_port, vid);
+		if (err)
+			last_err = err;
+	}
+
+	return last_err;
+}
+
+static int
+__mlxsw_sp_port_fdb_flush_lagged(const struct mlxsw_sp_port *mlxsw_sp_port)
+{
+	int err, last_err = 0;
+	u16 vid;
+
+	for (vid = 1; vid < VLAN_N_VID - 1; vid++) {
+		err = mlxsw_sp_port_fdb_flush_by_lag_id_fid(mlxsw_sp_port, vid);
+		if (err)
+			last_err = err;
+	}
+
+	return last_err;
+}
+
+static int mlxsw_sp_port_fdb_flush(struct mlxsw_sp_port *mlxsw_sp_port)
+{
+	if (!list_empty(&mlxsw_sp_port->vports_list))
+		if (mlxsw_sp_port->lagged)
+			return __mlxsw_sp_port_fdb_flush_lagged(mlxsw_sp_port);
+		else
+			return __mlxsw_sp_port_fdb_flush(mlxsw_sp_port);
+	else
+		if (mlxsw_sp_port->lagged)
+			return mlxsw_sp_port_fdb_flush_by_lag_id(mlxsw_sp_port);
+		else
+			return mlxsw_sp_port_fdb_flush_by_port(mlxsw_sp_port);
+}
+
+static int mlxsw_sp_vport_fdb_flush(struct mlxsw_sp_port *mlxsw_sp_vport)
+{
+	u16 vfid = mlxsw_sp_vport_vfid_get(mlxsw_sp_vport);
+	u16 fid = mlxsw_sp_vfid_to_fid(vfid);
+
+	if (mlxsw_sp_vport->lagged)
+		return mlxsw_sp_port_fdb_flush_by_lag_id_fid(mlxsw_sp_vport,
+							     fid);
+	else
+		return mlxsw_sp_port_fdb_flush_by_port_fid(mlxsw_sp_vport, fid);
+}
+
 static bool mlxsw_sp_port_dev_check(const struct net_device *dev)
 {
 	return dev->netdev_ops == &mlxsw_sp_port_netdev_ops;
@@ -2006,10 +2115,14 @@ static int mlxsw_sp_port_bridge_join(struct mlxsw_sp_port *mlxsw_sp_port)
 	return 0;
 }
 
-static int mlxsw_sp_port_bridge_leave(struct mlxsw_sp_port *mlxsw_sp_port)
+static int mlxsw_sp_port_bridge_leave(struct mlxsw_sp_port *mlxsw_sp_port,
+				      bool flush_fdb)
 {
 	struct net_device *dev = mlxsw_sp_port->dev;
 
+	if (flush_fdb && mlxsw_sp_port_fdb_flush(mlxsw_sp_port))
+		netdev_err(mlxsw_sp_port->dev, "Failed to flush FDB\n");
+
 	mlxsw_sp_port->learning = 0;
 	mlxsw_sp_port->learning_sync = 0;
 	mlxsw_sp_port->uc_flood = 0;
@@ -2201,7 +2314,8 @@ static int mlxsw_sp_port_lag_join(struct mlxsw_sp_port *mlxsw_sp_port,
 }
 
 static int mlxsw_sp_vport_bridge_leave(struct mlxsw_sp_port *mlxsw_sp_vport,
-				       struct net_device *br_dev);
+				       struct net_device *br_dev,
+				       bool flush_fdb);
 
 static int mlxsw_sp_port_lag_leave(struct mlxsw_sp_port *mlxsw_sp_port,
 				   struct net_device *lag_dev)
@@ -2236,18 +2350,20 @@ static int mlxsw_sp_port_lag_leave(struct mlxsw_sp_port *mlxsw_sp_port,
 			continue;
 
 		br_dev = mlxsw_sp_vport_br_get(mlxsw_sp_vport);
-		mlxsw_sp_vport_bridge_leave(mlxsw_sp_vport, br_dev);
+		mlxsw_sp_vport_bridge_leave(mlxsw_sp_vport, br_dev, false);
 	}
 
 	if (mlxsw_sp_port->bridged) {
 		mlxsw_sp_port_active_vlans_del(mlxsw_sp_port);
-		mlxsw_sp_port_bridge_leave(mlxsw_sp_port);
+		mlxsw_sp_port_bridge_leave(mlxsw_sp_port, false);
 
 		if (lag->ref_count == 1)
 			mlxsw_sp_master_bridge_dec(mlxsw_sp, NULL);
 	}
 
 	if (lag->ref_count == 1) {
+		if (mlxsw_sp_port_fdb_flush_by_lag_id(mlxsw_sp_port))
+			netdev_err(mlxsw_sp_port->dev, "Failed to flush FDB\n");
 		err = mlxsw_sp_lag_destroy(mlxsw_sp, lag_id);
 		if (err)
 			return err;
@@ -2336,7 +2452,7 @@ static int mlxsw_sp_port_vlan_unlink(struct mlxsw_sp_port *mlxsw_sp_port,
 		struct net_device *br_dev;
 
 		br_dev = mlxsw_sp_vport_br_get(mlxsw_sp_vport);
-		mlxsw_sp_vport_bridge_leave(mlxsw_sp_vport, br_dev);
+		mlxsw_sp_vport_bridge_leave(mlxsw_sp_vport, br_dev, true);
 	}
 
 	mlxsw_sp_vport->dev = mlxsw_sp_port->dev;
@@ -2398,7 +2514,8 @@ static int mlxsw_sp_netdevice_port_upper_event(struct net_device *dev,
 				}
 				mlxsw_sp_master_bridge_inc(mlxsw_sp, upper_dev);
 			} else {
-				err = mlxsw_sp_port_bridge_leave(mlxsw_sp_port);
+				err = mlxsw_sp_port_bridge_leave(mlxsw_sp_port,
+								 true);
 				mlxsw_sp_master_bridge_dec(mlxsw_sp, upper_dev);
 				if (err) {
 					netdev_err(dev, "Failed to leave bridge\n");
@@ -2565,7 +2682,8 @@ static void mlxsw_sp_br_vfid_destroy(struct mlxsw_sp *mlxsw_sp,
 }
 
 static int mlxsw_sp_vport_bridge_leave(struct mlxsw_sp_port *mlxsw_sp_vport,
-				       struct net_device *br_dev)
+				       struct net_device *br_dev,
+				       bool flush_fdb)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_vport->mlxsw_sp;
 	u16 vid = mlxsw_sp_vport_vid_get(mlxsw_sp_vport);
@@ -2628,6 +2746,9 @@ static int mlxsw_sp_vport_bridge_leave(struct mlxsw_sp_port *mlxsw_sp_vport,
 		goto err_vport_flood_set;
 	}
 
+	if (flush_fdb && mlxsw_sp_vport_fdb_flush(mlxsw_sp_vport))
+		netdev_err(dev, "Failed to flush FDB\n");
+
 	/* Switch between the vFIDs and destroy the old one if needed. */
 	new_vfid->nr_vports++;
 	mlxsw_sp_vport->vport.vfid = new_vfid;
@@ -2801,7 +2922,7 @@ static int mlxsw_sp_netdevice_vport_event(struct net_device *dev,
 			if (!mlxsw_sp_vport)
 				return NOTIFY_DONE;
 			err = mlxsw_sp_vport_bridge_leave(mlxsw_sp_vport,
-							  upper_dev);
+							  upper_dev, true);
 			if (err) {
 				netdev_err(dev, "Failed to leave bridge\n");
 				return NOTIFY_BAD;