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_private.h b/net/bridge/br_private.h
index 1b5d145..d9da857 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -560,8 +560,8 @@
 			    unsigned char flags);
 void br_mdb_init(void);
 void br_mdb_uninit(void);
-void br_mdb_notify(struct net_device *dev, struct net_bridge_port_group *pg,
-		   int type);
+void br_mdb_notify(struct net_device *dev, struct net_bridge_port *port,
+		   struct br_ip *group, int type, u8 flags);
 void br_rtr_notify(struct net_device *dev, struct net_bridge_port *port,
 		   int type);