[PATCHv3 next 2/3] blackhole_netdev: use blackhole_netdev to invalidate dst entries

[Mahesh Bandewar <maheshb@google.com>]

Use blackhole_netdev instead of 'lo' device with lower MTU when marking
dst "dead".

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
---
v1->v2->v3
  no change

 net/core/dst.c   | 2 +-
 net/ipv4/route.c | 3 +--
 net/ipv6/route.c | 2 +-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/net/core/dst.c b/net/core/dst.c
index e46366228eaf..1325316d9eab 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -160,7 +160,7 @@ void dst_dev_put(struct dst_entry *dst)
 		dst->ops->ifdown(dst, dev, true);
 	dst->input = dst_discard;
 	dst->output = dst_discard_out;
-	dst->dev = dev_net(dst->dev)->loopback_dev;
+	dst->dev = blackhole_netdev;
 	dev_hold(dst->dev);
 	dev_put(dev);
 }
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index bbd55c7f6b2e..dc1f510a7c81 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1532,7 +1532,6 @@ static void ipv4_dst_destroy(struct dst_entry *dst)
 
 void rt_flush_dev(struct net_device *dev)
 {
-	struct net *net = dev_net(dev);
 	struct rtable *rt;
 	int cpu;
 
@@ -1543,7 +1542,7 @@ void rt_flush_dev(struct net_device *dev)
 		list_for_each_entry(rt, &ul->head, rt_uncached) {
 			if (rt->dst.dev != dev)
 				continue;
-			rt->dst.dev = net->loopback_dev;
+			rt->dst.dev = blackhole_netdev;
 			dev_hold(rt->dst.dev);
 			dev_put(dev);
 		}
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 7556275b1cef..39361f57351a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -176,7 +176,7 @@ static void rt6_uncached_list_flush_dev(struct net *net, struct net_device *dev)
 			}
 
 			if (rt_dev == dev) {
-				rt->dst.dev = loopback_dev;
+				rt->dst.dev = blackhole_netdev;
 				dev_hold(rt->dst.dev);
 				dev_put(rt_dev);
 			}
-- 
2.22.0.410.gd8fdbe21b5-goog