mlxsw: spectrum: Remove reference count from VLAN entries

Commit b3529af6bb0d ("spectrum: Reference count VLAN entries") started
reference counting port-VLAN entries in a similar fashion to the 8021q
driver.

However, this is not actually needed and only complicates things.
Instead, the driver should forbid the creation of a VLAN on a port if
this VLAN already exists. This would also solve the issue fixed by the
mentioned commit.

Therefore, remove the get()/put() API and use create()/destroy()
instead.

One place that needs special attention is VLAN addition in a VLAN-aware
bridge via switchdev operations. In case the VLAN flags (e.g., 'pvid')
are toggled, then the VLAN entry already exists. To prevent the driver
from wrongly returning EEXIST, the driver is changed to check in the
prepare phase whether the entry already exists and only returns an error
in case it is not associated with the correct bridge port.

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, 26 insertions, 15 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
index 627efe7a6eef..0b2f724d9a0c 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
@@ -1021,10 +1021,8 @@ mlxsw_sp_port_vlan_bridge_join(struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan,
 	int err;
 
 	/* No need to continue if only VLAN flags were changed */
-	if (mlxsw_sp_port_vlan->bridge_port) {
-		mlxsw_sp_port_vlan_put(mlxsw_sp_port_vlan);
+	if (mlxsw_sp_port_vlan->bridge_port)
 		return 0;
-	}
 
 	err = mlxsw_sp_port_vlan_fid_join(mlxsw_sp_port_vlan, bridge_port,
 					  extack);
@@ -1105,16 +1103,32 @@ static int
 mlxsw_sp_bridge_port_vlan_add(struct mlxsw_sp_port *mlxsw_sp_port,
 			      struct mlxsw_sp_bridge_port *bridge_port,
 			      u16 vid, bool is_untagged, bool is_pvid,
-			      struct netlink_ext_ack *extack)
+			      struct netlink_ext_ack *extack,
+			      struct switchdev_trans *trans)
 {
 	u16 pvid = mlxsw_sp_port_pvid_determine(mlxsw_sp_port, vid, is_pvid);
 	struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan;
 	u16 old_pvid = mlxsw_sp_port->pvid;
 	int err;
 
-	mlxsw_sp_port_vlan = mlxsw_sp_port_vlan_get(mlxsw_sp_port, vid);
-	if (IS_ERR(mlxsw_sp_port_vlan))
-		return PTR_ERR(mlxsw_sp_port_vlan);
+	/* The only valid scenario in which a port-vlan already exists, is if
+	 * the VLAN flags were changed and the port-vlan is associated with the
+	 * correct bridge port
+	 */
+	mlxsw_sp_port_vlan = mlxsw_sp_port_vlan_find_by_vid(mlxsw_sp_port, vid);
+	if (mlxsw_sp_port_vlan &&
+	    mlxsw_sp_port_vlan->bridge_port != bridge_port)
+		return -EEXIST;
+
+	if (switchdev_trans_ph_prepare(trans))
+		return 0;
+
+	if (!mlxsw_sp_port_vlan) {
+		mlxsw_sp_port_vlan = mlxsw_sp_port_vlan_create(mlxsw_sp_port,
+							       vid);
+		if (IS_ERR(mlxsw_sp_port_vlan))
+			return PTR_ERR(mlxsw_sp_port_vlan);
+	}
 
 	err = mlxsw_sp_port_vlan_set(mlxsw_sp_port, vid, vid, true,
 				     is_untagged);
@@ -1137,7 +1151,7 @@ err_port_vlan_bridge_join:
 err_port_pvid_set:
 	mlxsw_sp_port_vlan_set(mlxsw_sp_port, vid, vid, false, false);
 err_port_vlan_set:
-	mlxsw_sp_port_vlan_put(mlxsw_sp_port_vlan);
+	mlxsw_sp_port_vlan_destroy(mlxsw_sp_port_vlan);
 	return err;
 }
 
@@ -1199,9 +1213,6 @@ static int mlxsw_sp_port_vlans_add(struct mlxsw_sp_port *mlxsw_sp_port,
 		return err;
 	}
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	bridge_port = mlxsw_sp_bridge_port_find(mlxsw_sp->bridge, orig_dev);
 	if (WARN_ON(!bridge_port))
 		return -EINVAL;
@@ -1214,7 +1225,7 @@ static int mlxsw_sp_port_vlans_add(struct mlxsw_sp_port *mlxsw_sp_port,
 
 		err = mlxsw_sp_bridge_port_vlan_add(mlxsw_sp_port, bridge_port,
 						    vid, flag_untagged,
-						    flag_pvid, extack);
+						    flag_pvid, extack, trans);
 		if (err)
 			return err;
 	}
@@ -1832,7 +1843,7 @@ mlxsw_sp_bridge_port_vlan_del(struct mlxsw_sp_port *mlxsw_sp_port,
 	mlxsw_sp_port_vlan_bridge_leave(mlxsw_sp_port_vlan);
 	mlxsw_sp_port_pvid_set(mlxsw_sp_port, pvid);
 	mlxsw_sp_port_vlan_set(mlxsw_sp_port, vid, vid, false, false);
-	mlxsw_sp_port_vlan_put(mlxsw_sp_port_vlan);
+	mlxsw_sp_port_vlan_destroy(mlxsw_sp_port_vlan);
 }
 
 static int mlxsw_sp_port_vlans_del(struct mlxsw_sp_port *mlxsw_sp_port,
@@ -2000,7 +2011,7 @@ mlxsw_sp_bridge_8021q_port_join(struct mlxsw_sp_bridge_device *bridge_device,
 		return -EINVAL;
 
 	/* Let VLAN-aware bridge take care of its own VLANs */
-	mlxsw_sp_port_vlan_put(mlxsw_sp_port_vlan);
+	mlxsw_sp_port_vlan_destroy(mlxsw_sp_port_vlan);
 
 	return 0;
 }
@@ -2010,7 +2021,7 @@ mlxsw_sp_bridge_8021q_port_leave(struct mlxsw_sp_bridge_device *bridge_device,
 				 struct mlxsw_sp_bridge_port *bridge_port,
 				 struct mlxsw_sp_port *mlxsw_sp_port)
 {
-	mlxsw_sp_port_vlan_get(mlxsw_sp_port, 1);
+	mlxsw_sp_port_vlan_create(mlxsw_sp_port, 1);
 	/* Make sure untagged frames are allowed to ingress */
 	mlxsw_sp_port_pvid_set(mlxsw_sp_port, 1);
 }