[PATCH net-next v3 1/2] ipv4: use rcu_assign_pointer() in rt_flush_dev()

[xuanqiang.luo@linux.dev]

From: Xuanqiang Luo <luoxuanqiang@kylinos.cn>

rt_flush_dev() replaces rt->dst.dev with blackhole_netdev on uncached
routes.  The field is also exposed as dst.dev_rcu, and existing readers
use dst_dev_rcu().

Use rcu_assign_pointer() for the replacement, as dst_dev_put() already
does for the same field.

Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
---
 net/ipv4/route.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 3f3de5164d6e5..b668375df71e2 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1565,7 +1565,7 @@ void rt_flush_dev(struct net_device *dev)
 		list_for_each_entry_safe(rt, safe, &ul->head, dst.rt_uncached) {
 			if (rt->dst.dev != dev)
 				continue;
-			rt->dst.dev = blackhole_netdev;
+			rcu_assign_pointer(rt->dst.dev_rcu, blackhole_netdev);
 			netdev_ref_replace(dev, blackhole_netdev,
 					   &rt->dst.dev_tracker, GFP_ATOMIC);
 			list_del_init(&rt->dst.rt_uncached);
-- 
2.43.0