Merge branch 'mpls-multipath-route-cleanups'

David Ahern says:

====================
net: mpls: multipath route cleanups

When a device associated with a nexthop is deleted, the nexthop in
the route is effectively removed, so remove it from the route dump.

Further, when all nexhops have been deleted the route is effectively
done, so remove the route.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/mpls/af_mpls.c

@@ -1299,7 +1299,7 @@ static void mpls_ifdown(struct net_device *dev, int event)
 	struct mpls_route __rcu **platform_label;
 	struct net *net = dev_net(dev);
 	unsigned int nh_flags = RTNH_F_DEAD | RTNH_F_LINKDOWN;
-	unsigned int alive;
+	unsigned int alive, deleted;
 	unsigned index;
 
 	platform_label = rtnl_dereference(net->mpls.platform_label);
@@ -1310,6 +1310,7 @@ static void mpls_ifdown(struct net_device *dev, int event)
 			continue;
 
 		alive = 0;
+		deleted = 0;
 		change_nexthops(rt) {
 			if (rtnl_dereference(nh->nh_dev) != dev)
 				goto next;
@@ -1328,9 +1329,15 @@ static void mpls_ifdown(struct net_device *dev, int event)
 next:
 			if (!(nh->nh_flags & nh_flags))
 				alive++;
+			if (!rtnl_dereference(nh->nh_dev))
+				deleted++;
 		} endfor_nexthops(rt);
 
 		WRITE_ONCE(rt->rt_nhn_alive, alive);
+
+		/* if there are no more nexthops, delete the route */
+		if (event == NETDEV_UNREGISTER && deleted == rt->rt_nhn)
+			mpls_route_update(net, index, NULL, NULL);
 	}
 }
 
@@ -1769,13 +1776,15 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
 			goto nla_put_failure;
 
 		for_nexthops(rt) {
+			dev = rtnl_dereference(nh->nh_dev);
+			if (!dev)
+				continue;
+
 			rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
 			if (!rtnh)
 				goto nla_put_failure;
 
-			dev = rtnl_dereference(nh->nh_dev);
-			if (dev)
-				rtnh->rtnh_ifindex = dev->ifindex;
+			rtnh->rtnh_ifindex = dev->ifindex;
 			if (nh->nh_flags & RTNH_F_LINKDOWN) {
 				rtnh->rtnh_flags |= RTNH_F_LINKDOWN;
 				linkdown++;