net: dsa: add port_vlan_dump routine

Similar to port_fdb_dump, add a port_vlan_dump function to DSA drivers
which gets passed the switchdev VLAN object and callback.

This function, if implemented, takes precedence over the soon legacy
vlan_getnext/port_pvid_get approach.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/dsa/dsa.txt

@@ -554,6 +554,10 @@ Bridge VLAN filtering
 - port_vlan_del: bridge layer function invoked when a VLAN is removed from the
   given switch port
 
+- port_vlan_dump: bridge layer function invoked with a switchdev callback
+  function that the driver has to call for each VLAN the given port is a member
+  of. A switchdev object is used to carry the VID and bridge flags.
+
 - vlan_getnext: bridge layer function invoked to query the next configured VLAN
   in the switch, i.e. returns the bitmaps of members and untagged ports
 

include/net/dsa.h

@@ -313,6 +313,9 @@ struct dsa_switch_driver {
 				 struct switchdev_trans *trans);
 	int	(*port_vlan_del)(struct dsa_switch *ds, int port,
 				 const struct switchdev_obj_port_vlan *vlan);
+	int	(*port_vlan_dump)(struct dsa_switch *ds, int port,
+				  struct switchdev_obj_port_vlan *vlan,
+				  int (*cb)(struct switchdev_obj *obj));
 	int	(*port_pvid_get)(struct dsa_switch *ds, int port, u16 *pvid);
 	int	(*vlan_getnext)(struct dsa_switch *ds, u16 *vid,
 				unsigned long *ports, unsigned long *untagged);

net/dsa/slave.c

@@ -248,6 +248,9 @@ static int dsa_slave_port_vlan_dump(struct net_device *dev,
 	u16 pvid, vid = 0;
 	int err;
 
+	if (ds->drv->port_vlan_dump)
+		return ds->drv->port_vlan_dump(ds, p->port, vlan, cb);
+
 	if (!ds->drv->vlan_getnext || !ds->drv->port_pvid_get)
 		return -EOPNOTSUPP;