net: bridge: mcast: fix vlan port router deadlock

Before vlan/port mcast router support was added
br_multicast_set_port_router was used only with bh already disabled due
to the bridge port lock, but that is no longer the case and when it is
called to configure a vlan/port mcast router we can deadlock with the
timer, so always disable bh to make sure it can be called from contexts
with both enabled and disabled bh.

Fixes: 2796d846 ("net: bridge: vlan: convert mcast router global option to per-vlan entry")
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_multicast.c

@@ -4255,7 +4255,7 @@ int br_multicast_set_port_router(struct net_bridge_mcast_port *pmctx,
 	bool del = false;
 
 	brmctx = br_multicast_port_ctx_get_global(pmctx);
-	spin_lock(&brmctx->br->multicast_lock);
+	spin_lock_bh(&brmctx->br->multicast_lock);
 	if (pmctx->multicast_router == val) {
 		/* Refresh the temp router port timer */
 		if (pmctx->multicast_router == MDB_RTR_TYPE_TEMP) {
@@ -4305,7 +4305,7 @@ int br_multicast_set_port_router(struct net_bridge_mcast_port *pmctx,
 	}
 	err = 0;
 unlock:
-	spin_unlock(&brmctx->br->multicast_lock);
+	spin_unlock_bh(&brmctx->br->multicast_lock);
 
 	return err;
 }