[PATCH 5.16 131/227] net: bridge: multicast: notify switchdev driver whenever MC processing gets disabled

[Greg Kroah-Hartman]

From: Oleksandr Mazur <oleksandr.mazur@xxxxxxxxxxx>

commit c832962ac972082b3a1f89775c9d4274c8cb5670 upstream.

Whenever bridge driver hits the max capacity of MDBs, it disables
the MC processing (by setting corresponding bridge option), but never
notifies switchdev about such change (the notifiers are called only upon
explicit setting of this option, through the registered netlink interface).

This could lead to situation when Software MDB processing gets disabled,
but this event never gets offloaded to the underlying Hardware.

Fix this by adding a notify message in such case.

Fixes: 147c1e9b902c ("switchdev: bridge: Offload multicast disabled")
Signed-off-by: Oleksandr Mazur <oleksandr.mazur@xxxxxxxxxxx>
Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220215165303.31908-1-oleksandr.mazur@xxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/bridge/br_multicast.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -82,6 +82,9 @@ static void br_multicast_find_del_pg(str
 				     struct net_bridge_port_group *pg);
 static void __br_multicast_stop(struct net_bridge_mcast *brmctx);
 
+static int br_mc_disabled_update(struct net_device *dev, bool value,
+				 struct netlink_ext_ack *extack);
+
 static struct net_bridge_port_group *
 br_sg_port_find(struct net_bridge *br,
 		struct net_bridge_port_group_sg_key *sg_p)
@@ -1156,6 +1159,7 @@ struct net_bridge_mdb_entry *br_multicas
 		return mp;
 
 	if (atomic_read(&br->mdb_hash_tbl.nelems) >= br->hash_max) {
+		br_mc_disabled_update(br->dev, false, NULL);
 		br_opt_toggle(br, BROPT_MULTICAST_ENABLED, false);
 		return ERR_PTR(-E2BIG);
 	}