net: bridge: mcast: Notify on mdb offload failure

Notify user space on mdb offload failure if
mdb_offload_fail_notification is enabled.

Signed-off-by: Joseph Huang <[e-mail]>
Acked-by: Nikolay Aleksandrov <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/bridge/br_mdb.c

···
 	       rtnl_mdb_nlmsg_pg_size(pg);
 }
 
-void br_mdb_notify(struct net_device *dev,
-		   struct net_bridge_mdb_entry *mp,
-		   struct net_bridge_port_group *pg,
-		   int type)
+static void __br_mdb_notify(struct net_device *dev,
+			    struct net_bridge_mdb_entry *mp,
+			    struct net_bridge_port_group *pg,
+			    int type, bool notify_switchdev)
 {
 	struct net *net = dev_net(dev);
 	struct sk_buff *skb;
 	int err = -ENOBUFS;
 
-	br_switchdev_mdb_notify(dev, mp, pg, type);
+	if (notify_switchdev)
+		br_switchdev_mdb_notify(dev, mp, pg, type);
 
 	skb = nlmsg_new(rtnl_mdb_nlmsg_size(pg), GFP_ATOMIC);
 	if (!skb)
···
 	return;
 errout:
 	rtnl_set_sk_err(net, RTNLGRP_MDB, err);
+}
+
+void br_mdb_notify(struct net_device *dev,
+		   struct net_bridge_mdb_entry *mp,
+		   struct net_bridge_port_group *pg,
+		   int type)
+{
+	__br_mdb_notify(dev, mp, pg, type, true);
+}
+
+void br_mdb_flag_change_notify(struct net_device *dev,
+			       struct net_bridge_mdb_entry *mp,
+			       struct net_bridge_port_group *pg)
+{
+	__br_mdb_notify(dev, mp, pg, RTM_NEWMDB, false);
 }
 
 static int nlmsg_populate_rtr_fill(struct sk_buff *skb,

net/bridge/br_private.h

···
 void br_mdb_hash_fini(struct net_bridge *br);
 void br_mdb_notify(struct net_device *dev, struct net_bridge_mdb_entry *mp,
 		   struct net_bridge_port_group *pg, int type);
+void br_mdb_flag_change_notify(struct net_device *dev, struct net_bridge_mdb_entry *mp,
+			       struct net_bridge_port_group *pg);
 void br_rtr_notify(struct net_device *dev, struct net_bridge_mcast_port *pmctx,
 		   int type);
 void br_multicast_del_pg(struct net_bridge_mdb_entry *mp,
···
 	p->flags &= ~(MDB_PG_FLAGS_OFFLOAD | MDB_PG_FLAGS_OFFLOAD_FAILED);
 	p->flags |= (offloaded ? MDB_PG_FLAGS_OFFLOAD :
 		MDB_PG_FLAGS_OFFLOAD_FAILED);
+}
+
+static inline bool
+br_mdb_should_notify(const struct net_bridge *br, u8 changed_flags)
+{
+	return br_opt_get(br, BROPT_MDB_OFFLOAD_FAIL_NOTIFICATION) &&
+		(changed_flags & MDB_PG_FLAGS_OFFLOAD_FAILED);
 }
 #else
 static inline int br_multicast_rcv(struct net_bridge_mcast **brmctx,

net/bridge/br_switchdev.c

···
 	struct net_bridge_mdb_entry *mp;
 	struct net_bridge_port *port = data->port;
 	struct net_bridge *br = port->br;
+	u8 old_flags;
 
 	if (err == -EOPNOTSUPP)
 		goto out_free;
···
 		if (p->key.port != port)
 			continue;
 
+		old_flags = p->flags;
 		br_multicast_set_pg_offload_flags(p, !err);
+		if (br_mdb_should_notify(br, old_flags ^ p->flags))
+			br_mdb_flag_change_notify(br->dev, mp, p);
 	}
 out:
 	spin_unlock_bh(&br->multicast_lock);