net: bridge: add helper to replay VLANs installed on port

Currently this simple setup with DSA:

ip link add br0 type bridge vlan_filtering 1
ip link add bond0 type bond
ip link set bond0 master br0
ip link set swp0 master bond0

will not work because the bridge has created the PVID in br_add_if ->
nbp_vlan_init, and it has notified switchdev of the existence of VLAN 1,
but that was too early, since swp0 was not yet a lower of bond0, so it
had no reason to act upon that notification.

We need a helper in the bridge to replay the switchdev VLAN objects that
were notified since the bridge port creation, because some of them may
have been missed.

As opposed to the br_mdb_replay function, the vg->vlan_list write side
protection is offered by the rtnl_mutex which is sleepable, so we don't
need to queue up the objects in atomic context, we can replay them right
away.

Signed-off-by: Vladimir Oltean <[email protected]>
Acked-by: Nikolay Aleksandrov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: vladimiroltean

include/linux/if_bridge.h

@@ -111,6 +111,8 @@ int br_vlan_get_pvid_rcu(const struct net_device *dev, u16 *p_pvid);
 int br_vlan_get_proto(const struct net_device *dev, u16 *p_proto);
 int br_vlan_get_info(const struct net_device *dev, u16 vid,
 		     struct bridge_vlan_info *p_vinfo);
+int br_vlan_replay(struct net_device *br_dev, struct net_device *dev,
+		   struct notifier_block *nb, struct netlink_ext_ack *extack);
 #else
 static inline bool br_vlan_enabled(const struct net_device *dev)
 {
@@ -137,6 +139,14 @@ static inline int br_vlan_get_info(const struct net_device *dev, u16 vid,
 {
 	return -EINVAL;
 }
+
+static inline int br_vlan_replay(struct net_device *br_dev,
+				 struct net_device *dev,
+				 struct notifier_block *nb,
+				 struct netlink_ext_ack *extack)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 #if IS_ENABLED(CONFIG_BRIDGE)

net/bridge/br_vlan.c

@@ -1751,6 +1751,79 @@ void br_vlan_notify(const struct net_bridge *br,
 	kfree_skb(skb);
 }
 
+static int br_vlan_replay_one(struct notifier_block *nb,
+			      struct net_device *dev,
+			      struct switchdev_obj_port_vlan *vlan,
+			      struct netlink_ext_ack *extack)
+{
+	struct switchdev_notifier_port_obj_info obj_info = {
+		.info = {
+			.dev = dev,
+			.extack = extack,
+		},
+		.obj = &vlan->obj,
+	};
+	int err;
+
+	err = nb->notifier_call(nb, SWITCHDEV_PORT_OBJ_ADD, &obj_info);
+	return notifier_to_errno(err);
+}
+
+int br_vlan_replay(struct net_device *br_dev, struct net_device *dev,
+		   struct notifier_block *nb, struct netlink_ext_ack *extack)
+{
+	struct net_bridge_vlan_group *vg;
+	struct net_bridge_vlan *v;
+	struct net_bridge_port *p;
+	struct net_bridge *br;
+	int err = 0;
+	u16 pvid;
+
+	ASSERT_RTNL();
+
+	if (!netif_is_bridge_master(br_dev))
+		return -EINVAL;
+
+	if (!netif_is_bridge_master(dev) && !netif_is_bridge_port(dev))
+		return -EINVAL;
+
+	if (netif_is_bridge_master(dev)) {
+		br = netdev_priv(dev);
+		vg = br_vlan_group(br);
+		p = NULL;
+	} else {
+		p = br_port_get_rtnl(dev);
+		if (WARN_ON(!p))
+			return -EINVAL;
+		vg = nbp_vlan_group(p);
+		br = p->br;
+	}
+
+	if (!vg)
+		return 0;
+
+	pvid = br_get_pvid(vg);
+
+	list_for_each_entry(v, &vg->vlan_list, vlist) {
+		struct switchdev_obj_port_vlan vlan = {
+			.obj.orig_dev = dev,
+			.obj.id = SWITCHDEV_OBJ_ID_PORT_VLAN,
+			.flags = br_vlan_flags(v, pvid),
+			.vid = v->vid,
+		};
+
+		if (!br_vlan_should_use(v))
+			continue;
+
+		br_vlan_replay_one(nb, dev, &vlan, extack);
+		if (err)
+			return err;
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(br_vlan_replay);
+
 /* check if v_curr can enter a range ending in range_end */
 bool br_vlan_can_enter_range(const struct net_bridge_vlan *v_curr,
 			     const struct net_bridge_vlan *range_end)