mlxsw: spectrum: Properly cleanup LAG uppers when removing port from LAG

When a LAG device or a VLAN device on top of it is enslaved to a bridge,
the driver propagates the CHANGEUPPER event to the LAG's slaves.

This causes each physical port to increase the reference count of the
internal representation of the bridge port by calling
mlxsw_sp_port_bridge_join().

However, when a port is removed from a LAG, the corresponding leave()
function is not called and the reference count is not decremented. This
leads to ugly hacks such as mlxsw_sp_bridge_port_should_destroy() that
try to understand if the bridge port should be destroyed even when its
reference count is not 0.

Instead, make sure that when a port is unlinked from a LAG it would see
the same events as if the LAG (or its uppers) were unlinked from a
bridge.

The above is achieved by walking the LAG's uppers when a port is
unlinked and calling mlxsw_sp_port_bridge_leave() for each upper that is
enslaved to a bridge.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 7777528f67fb..d0235aa2aebc 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -4498,6 +4498,25 @@ void mlxsw_sp_port_dev_put(struct mlxsw_sp_port *mlxsw_sp_port)
 	dev_put(mlxsw_sp_port->dev);
 }
 
+static void
+mlxsw_sp_port_lag_uppers_cleanup(struct mlxsw_sp_port *mlxsw_sp_port,
+				 struct net_device *lag_dev)
+{
+	struct net_device *br_dev = netdev_master_upper_dev_get(lag_dev);
+	struct net_device *upper_dev;
+	struct list_head *iter;
+
+	if (netif_is_bridge_port(lag_dev))
+		mlxsw_sp_port_bridge_leave(mlxsw_sp_port, lag_dev, br_dev);
+
+	netdev_for_each_upper_dev_rcu(lag_dev, upper_dev, iter) {
+		if (!netif_is_bridge_port(upper_dev))
+			continue;
+		br_dev = netdev_master_upper_dev_get(upper_dev);
+		mlxsw_sp_port_bridge_leave(mlxsw_sp_port, upper_dev, br_dev);
+	}
+}
+
 static int mlxsw_sp_lag_create(struct mlxsw_sp *mlxsw_sp, u16 lag_id)
 {
 	char sldr_pl[MLXSW_REG_SLDR_LEN];
@@ -4690,6 +4709,10 @@ static void mlxsw_sp_port_lag_leave(struct mlxsw_sp_port *mlxsw_sp_port,
 
 	/* Any VLANs configured on the port are no longer valid */
 	mlxsw_sp_port_vlan_flush(mlxsw_sp_port);
+	/* Make the LAG and its directly linked uppers leave bridges they
+	 * are memeber in
+	 */
+	mlxsw_sp_port_lag_uppers_cleanup(mlxsw_sp_port, lag_dev);
 
 	if (lag->ref_count == 1)
 		mlxsw_sp_lag_destroy(mlxsw_sp, lag_id);