[PATCH v1 net-next 7/7] nexthop: Convert RTM_DELNEXTHOP to per-netns RTNL.

[Kuniyuki Iwashima <kuniyu@amazon.com>]

In rtm_del_nexthop(), only nexthop_find_by_id() and remove_nexthop()
require RTNL as they touch net->nexthop.rb_root.

Let's move RTNL down as rtnl_net_lock() before nexthop_find_by_id().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv4/nexthop.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index ea62454e0a0c..66d7796ba174 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -3314,13 +3314,17 @@ static int rtm_del_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err)
 		return err;
 
+	rtnl_net_lock(net);
+
 	nh = nexthop_find_by_id(net, id);
-	if (!nh)
-		return -ENOENT;
+	if (nh)
+		remove_nexthop(net, nh, &nlinfo);
+	else
+		err = -ENOENT;
 
-	remove_nexthop(net, nh, &nlinfo);
+	rtnl_net_unlock(net);
 
-	return 0;
+	return err;
 }
 
 /* rtnl */
@@ -4074,7 +4078,8 @@ static struct pernet_operations nexthop_net_ops = {
 static const struct rtnl_msg_handler nexthop_rtnl_msg_handlers[] __initconst = {
 	{.msgtype = RTM_NEWNEXTHOP, .doit = rtm_new_nexthop,
 	 .flags = RTNL_FLAG_DOIT_PERNET},
-	{.msgtype = RTM_DELNEXTHOP, .doit = rtm_del_nexthop},
+	{.msgtype = RTM_DELNEXTHOP, .doit = rtm_del_nexthop,
+	 .flags = RTNL_FLAG_DOIT_PERNET},
 	{.msgtype = RTM_GETNEXTHOP, .doit = rtm_get_nexthop,
 	 .dumpit = rtm_dump_nexthop},
 	{.msgtype = RTM_GETNEXTHOPBUCKET, .doit = rtm_get_nexthop_bucket,
-- 
2.48.1