FAILED: patch "[PATCH] net: bridge: multicast: notify switchdev driver whenever MC" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c832962ac972082b3a1f89775c9d4274c8cb5670 Mon Sep 17 00:00:00 2001
From: Oleksandr Mazur <[email protected]>
Date: Tue, 15 Feb 2022 18:53:03 +0200
Subject: [PATCH] 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.

index de2409889489..db4f2641d1cd 100644
@@ -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);
 	}