bridge: mdb: Marking port-group as offloaded

There is a race-condition when updating the mdb offload flag without using
the mulicast_lock. This reverts commit 9e8430f8d60d98 ("bridge: mdb:
Passing the port-group pointer to br_mdb module").

This patch marks offloaded MDB entry as "offload" by changing the port-
group flags and marks it as MDB_PG_FLAGS_OFFLOAD.

When switchdev PORT_MDB succeeded and adds a multicast group, a completion
callback is been invoked "br_mdb_complete". The completion function
locks the multicast_lock and finds the right net_bridge_port_group and
marks it as offloaded.

Fixes: 9e8430f8d60d98 ("bridge: mdb: Passing the port-group pointer to br_mdb module")
Reported-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Elad Raz <eladr@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index a4c15df..191ea66 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -283,7 +283,8 @@
 		rcu_assign_pointer(*pp, p->next);
 		hlist_del_init(&p->mglist);
 		del_timer(&p->timer);
-		br_mdb_notify(br->dev, p, RTM_DELMDB);
+		br_mdb_notify(br->dev, p->port, &pg->addr, RTM_DELMDB,
+			      p->flags);
 		call_rcu_bh(&p->rcu, br_multicast_free_pg);
 
 		if (!mp->ports && !mp->mglist &&
@@ -705,7 +706,7 @@
 	if (unlikely(!p))
 		goto err;
 	rcu_assign_pointer(*pp, p);
-	br_mdb_notify(br->dev, p, RTM_NEWMDB);
+	br_mdb_notify(br->dev, port, group, RTM_NEWMDB, 0);
 
 found:
 	mod_timer(&p->timer, now + br->multicast_membership_interval);
@@ -1461,7 +1462,8 @@
 			hlist_del_init(&p->mglist);
 			del_timer(&p->timer);
 			call_rcu_bh(&p->rcu, br_multicast_free_pg);
-			br_mdb_notify(br->dev, p, RTM_DELMDB);
+			br_mdb_notify(br->dev, port, group, RTM_DELMDB,
+				      p->flags);
 
 			if (!mp->ports && !mp->mglist &&
 			    netif_running(br->dev))