mlxsw: spectrum: Remove reference count from VLAN entries

Commit b3529af6 ("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>

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

@@ -1141,16 +1141,20 @@ static void mlxsw_sp_port_vlan_flush(struct mlxsw_sp_port *mlxsw_sp_port)
 
 	list_for_each_entry_safe(mlxsw_sp_port_vlan, tmp,
 				 &mlxsw_sp_port->vlans_list, list)
-		mlxsw_sp_port_vlan_put(mlxsw_sp_port_vlan);
+		mlxsw_sp_port_vlan_destroy(mlxsw_sp_port_vlan);
 }
 
-static struct mlxsw_sp_port_vlan *
+struct mlxsw_sp_port_vlan *
 mlxsw_sp_port_vlan_create(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid)
 {
 	struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan;
 	bool untagged = vid == 1;
 	int err;
 
+	mlxsw_sp_port_vlan = mlxsw_sp_port_vlan_find_by_vid(mlxsw_sp_port, vid);
+	if (mlxsw_sp_port_vlan)
+		return ERR_PTR(-EEXIST);
+
 	err = mlxsw_sp_port_vlan_set(mlxsw_sp_port, vid, vid, true, untagged);
 	if (err)
 		return ERR_PTR(err);
@@ -1162,7 +1166,6 @@ mlxsw_sp_port_vlan_create(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid)
 	}
 
 	mlxsw_sp_port_vlan->mlxsw_sp_port = mlxsw_sp_port;
-	mlxsw_sp_port_vlan->ref_count = 1;
 	mlxsw_sp_port_vlan->vid = vid;
 	list_add(&mlxsw_sp_port_vlan->list, &mlxsw_sp_port->vlans_list);
 
@@ -1173,44 +1176,19 @@ mlxsw_sp_port_vlan_create(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid)
 	return ERR_PTR(err);
 }
 
-static void
-mlxsw_sp_port_vlan_destroy(struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan)
+void mlxsw_sp_port_vlan_destroy(struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan)
 {
 	struct mlxsw_sp_port *mlxsw_sp_port = mlxsw_sp_port_vlan->mlxsw_sp_port;
 	u16 vid = mlxsw_sp_port_vlan->vid;
 
-	list_del(&mlxsw_sp_port_vlan->list);
-	kfree(mlxsw_sp_port_vlan);
-	mlxsw_sp_port_vlan_set(mlxsw_sp_port, vid, vid, false, false);
-}
-
-struct mlxsw_sp_port_vlan *
-mlxsw_sp_port_vlan_get(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid)
-{
-	struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan;
-
-	mlxsw_sp_port_vlan = mlxsw_sp_port_vlan_find_by_vid(mlxsw_sp_port, vid);
-	if (mlxsw_sp_port_vlan) {
-		mlxsw_sp_port_vlan->ref_count++;
-		return mlxsw_sp_port_vlan;
-	}
-
-	return mlxsw_sp_port_vlan_create(mlxsw_sp_port, vid);
-}
-
-void mlxsw_sp_port_vlan_put(struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan)
-{
-	struct mlxsw_sp_fid *fid = mlxsw_sp_port_vlan->fid;
-
-	if (--mlxsw_sp_port_vlan->ref_count != 0)
-		return;
-
 	if (mlxsw_sp_port_vlan->bridge_port)
 		mlxsw_sp_port_vlan_bridge_leave(mlxsw_sp_port_vlan);
-	else if (fid)
+	else if (mlxsw_sp_port_vlan->fid)
 		mlxsw_sp_port_vlan_router_leave(mlxsw_sp_port_vlan);
 
-	mlxsw_sp_port_vlan_destroy(mlxsw_sp_port_vlan);
+	list_del(&mlxsw_sp_port_vlan->list);
+	kfree(mlxsw_sp_port_vlan);
+	mlxsw_sp_port_vlan_set(mlxsw_sp_port, vid, vid, false, false);
 }
 
 static int mlxsw_sp_port_add_vid(struct net_device *dev,
@@ -1224,7 +1202,7 @@ static int mlxsw_sp_port_add_vid(struct net_device *dev,
 	if (!vid)
 		return 0;
 
-	return PTR_ERR_OR_ZERO(mlxsw_sp_port_vlan_get(mlxsw_sp_port, vid));
+	return PTR_ERR_OR_ZERO(mlxsw_sp_port_vlan_create(mlxsw_sp_port, vid));
 }
 
 static int mlxsw_sp_port_kill_vid(struct net_device *dev,
@@ -1242,7 +1220,7 @@ static int mlxsw_sp_port_kill_vid(struct net_device *dev,
 	mlxsw_sp_port_vlan = mlxsw_sp_port_vlan_find_by_vid(mlxsw_sp_port, vid);
 	if (!mlxsw_sp_port_vlan)
 		return 0;
-	mlxsw_sp_port_vlan_put(mlxsw_sp_port_vlan);
+	mlxsw_sp_port_vlan_destroy(mlxsw_sp_port_vlan);
 
 	return 0;
 }
@@ -3198,12 +3176,12 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port,
 		goto err_port_nve_init;
 	}
 
-	mlxsw_sp_port_vlan = mlxsw_sp_port_vlan_get(mlxsw_sp_port, 1);
+	mlxsw_sp_port_vlan = mlxsw_sp_port_vlan_create(mlxsw_sp_port, 1);
 	if (IS_ERR(mlxsw_sp_port_vlan)) {
 		dev_err(mlxsw_sp->bus_info->dev, "Port %d: Failed to create VID 1\n",
 			mlxsw_sp_port->local_port);
 		err = PTR_ERR(mlxsw_sp_port_vlan);
-		goto err_port_vlan_get;
+		goto err_port_vlan_create;
 	}
 
 	mlxsw_sp_port_switchdev_init(mlxsw_sp_port);
@@ -3224,8 +3202,8 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port,
 err_register_netdev:
 	mlxsw_sp->ports[local_port] = NULL;
 	mlxsw_sp_port_switchdev_fini(mlxsw_sp_port);
-	mlxsw_sp_port_vlan_put(mlxsw_sp_port_vlan);
-err_port_vlan_get:
+	mlxsw_sp_port_vlan_destroy(mlxsw_sp_port_vlan);
+err_port_vlan_create:
 	mlxsw_sp_port_nve_fini(mlxsw_sp_port);
 err_port_nve_init:
 	mlxsw_sp_tc_qdisc_fini(mlxsw_sp_port);
@@ -4721,7 +4699,7 @@ static void mlxsw_sp_port_lag_leave(struct mlxsw_sp_port *mlxsw_sp_port,
 	mlxsw_sp_port->lagged = 0;
 	lag->ref_count--;
 
-	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);
 }

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

@@ -190,7 +190,6 @@ struct mlxsw_sp_port_vlan {
 	struct list_head list;
 	struct mlxsw_sp_port *mlxsw_sp_port;
 	struct mlxsw_sp_fid *fid;
-	unsigned int ref_count;
 	u16 vid;
 	struct mlxsw_sp_bridge_port *bridge_port;
 	struct list_head bridge_vlan_node;
@@ -410,8 +409,8 @@ int mlxsw_sp_port_vid_learning_set(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid,
 				   bool learn_enable);
 int mlxsw_sp_port_pvid_set(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid);
 struct mlxsw_sp_port_vlan *
-mlxsw_sp_port_vlan_get(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid);
-void mlxsw_sp_port_vlan_put(struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan);
+mlxsw_sp_port_vlan_create(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid);
+void mlxsw_sp_port_vlan_destroy(struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan);
 int mlxsw_sp_port_vlan_set(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid_begin,
 			   u16 vid_end, bool is_member, bool untagged);
 int mlxsw_sp_flow_counter_get(struct mlxsw_sp *mlxsw_sp,

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);
+	/* 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 @@ mlxsw_sp_bridge_port_vlan_add(struct mlxsw_sp_port *mlxsw_sp_port,
 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);
 }