net: dsa: slave: Handle SWITCHDEV_PORT_OBJ_ADD/_DEL

Following patches will change the way of distributing port object
changes from a switchdev operation to a switchdev notifier. The
switchdev code currently recursively descends through layers of lower
devices, eventually calling the op on a front-panel port device. The
notifier will instead be sent referencing the bridge port device, which
may be a stacking device that's one of front-panel ports uppers, or a
completely unrelated device.

DSA currently doesn't support any other uppers than bridge.
SWITCHDEV_OBJ_ID_HOST_MDB and _PORT_MDB objects are always notified on
the bridge port device. Thus the only case that a stacked device could
be validly referenced by port object notifications are bridge
notifications for VLAN objects added to the bridge itself. But the
driver explicitly rejects such notifications in dsa_port_vlan_add(). It
is therefore safe to assume that the only interesting case is that the
notification is on a front-panel port netdevice. Therefore keep the
filtering by dsa_slave_dev_check() in place.

To handle SWITCHDEV_PORT_OBJ_ADD and _DEL, subscribe to the blocking
notifier chain. Dispatch to rocker_port_obj_add() resp. _del() to
maintain the behavior that the switchdev operation based code currently
has.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/slave.c

@@ -1557,6 +1557,44 @@ static int dsa_slave_switchdev_event(struct notifier_block *unused,
 	return NOTIFY_BAD;
 }
 
+static int
+dsa_slave_switchdev_port_obj_event(unsigned long event,
+			struct net_device *netdev,
+			struct switchdev_notifier_port_obj_info *port_obj_info)
+{
+	int err = -EOPNOTSUPP;
+
+	switch (event) {
+	case SWITCHDEV_PORT_OBJ_ADD:
+		err = dsa_slave_port_obj_add(netdev, port_obj_info->obj,
+					     port_obj_info->trans);
+		break;
+	case SWITCHDEV_PORT_OBJ_DEL:
+		err = dsa_slave_port_obj_del(netdev, port_obj_info->obj);
+		break;
+	}
+
+	port_obj_info->handled = true;
+	return notifier_from_errno(err);
+}
+
+static int dsa_slave_switchdev_blocking_event(struct notifier_block *unused,
+					      unsigned long event, void *ptr)
+{
+	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
+
+	if (!dsa_slave_dev_check(dev))
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case SWITCHDEV_PORT_OBJ_ADD: /* fall through */
+	case SWITCHDEV_PORT_OBJ_DEL:
+		return dsa_slave_switchdev_port_obj_event(event, dev, ptr);
+	}
+
+	return NOTIFY_DONE;
+}
+
 static struct notifier_block dsa_slave_nb __read_mostly = {
 	.notifier_call  = dsa_slave_netdevice_event,
 };
@@ -1565,8 +1603,13 @@ static struct notifier_block dsa_slave_switchdev_notifier = {
 	.notifier_call = dsa_slave_switchdev_event,
 };
 
+static struct notifier_block dsa_slave_switchdev_blocking_notifier = {
+	.notifier_call = dsa_slave_switchdev_blocking_event,
+};
+
 int dsa_slave_register_notifier(void)
 {
+	struct notifier_block *nb;
 	int err;
 
 	err = register_netdevice_notifier(&dsa_slave_nb);
@@ -1577,8 +1620,15 @@ int dsa_slave_register_notifier(void)
 	if (err)
 		goto err_switchdev_nb;
 
+	nb = &dsa_slave_switchdev_blocking_notifier;
+	err = register_switchdev_blocking_notifier(nb);
+	if (err)
+		goto err_switchdev_blocking_nb;
+
 	return 0;
 
+err_switchdev_blocking_nb:
+	unregister_switchdev_notifier(&dsa_slave_switchdev_notifier);
 err_switchdev_nb:
 	unregister_netdevice_notifier(&dsa_slave_nb);
 	return err;
@@ -1586,8 +1636,14 @@ int dsa_slave_register_notifier(void)
 
 void dsa_slave_unregister_notifier(void)
 {
+	struct notifier_block *nb;
 	int err;
 
+	nb = &dsa_slave_switchdev_blocking_notifier;
+	err = unregister_switchdev_blocking_notifier(nb);
+	if (err)
+		pr_err("DSA: failed to unregister switchdev blocking notifier (%d)\n", err);
+
 	err = unregister_switchdev_notifier(&dsa_slave_switchdev_notifier);
 	if (err)
 		pr_err("DSA: failed to unregister switchdev notifier (%d)\n", err);