net: bridge: multicast: notify switchdev driver whenever MC processing gets disabled

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: d79114a8db04 ("switchdev: bridge: Offload multicast disabled")
Signed-off-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Link: https://lore.kernel.org/r/20220215165303.31908-1-oleksandr.mazur@plvision.eu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index de24098894897270bbae00f5efe546a05728cc7a..db4f2641d1cd1e963de1695ad3e46d1a15761ab6 100644 (file)
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -82,6 +82,9 @@ static void br_multicast_find_del_pg(struct net_bridge *br,
                                     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_multicast_new_group(struct net_bridge *br,
                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);
        }