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: David S. Miller <[e-mail]>

net/mpls/af_mpls.c

···
 	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);
···
 			continue;
 
 		alive = 0;
+		deleted = 0;
 		change_nexthops(rt) {
 			if (rtnl_dereference(nh->nh_dev) != dev)
 				goto next;
···
 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);
 	}
 }
 
···
 			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++;