[PATCH v2 net-next 02/14] rtnetlink: Call unregister_netdevice_many() only once in rtnl_link_unregister().

[Kuniyuki Iwashima <kuniyu@google.com>]

When rtnl_link_unregister() is called during module unload, it
calls __rtnl_kill_links() for every netns.

__rtnl_kill_links() collects all devices of the unloaded module
and passes them to unregister_netdevice_many().

Let's move unregister_netdevice_many() to rtnl_link_unregister()
to unregister all devices across netns in a single batch.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
 net/core/rtnetlink.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f39c93e80e20..7207da002fb5 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -637,16 +637,15 @@ int rtnl_link_register(struct rtnl_link_ops *ops)
 }
 EXPORT_SYMBOL_GPL(rtnl_link_register);
 
-static void __rtnl_kill_links(struct net *net, struct rtnl_link_ops *ops)
+static void __rtnl_kill_links(struct net *net, struct rtnl_link_ops *ops,
+			      struct list_head *dev_kill_list)
 {
 	struct net_device *dev;
-	LIST_HEAD(list_kill);
 
 	for_each_netdev(net, dev) {
 		if (dev->rtnl_link_ops == ops)
-			ops->dellink(dev, &list_kill);
+			ops->dellink(dev, dev_kill_list);
 	}
-	unregister_netdevice_many(&list_kill);
 }
 
 /* Return with the rtnl_lock held when there are no network
@@ -677,6 +676,7 @@ static void rtnl_lock_unregistering_all(void)
  */
 void rtnl_link_unregister(struct rtnl_link_ops *ops)
 {
+	LIST_HEAD(dev_kill_list);
 	struct net *net;
 
 	mutex_lock(&link_ops_mutex);
@@ -691,7 +691,9 @@ void rtnl_link_unregister(struct rtnl_link_ops *ops)
 	rtnl_lock_unregistering_all();
 
 	for_each_net(net)
-		__rtnl_kill_links(net, ops);
+		__rtnl_kill_links(net, ops, &dev_kill_list);
+
+	unregister_netdevice_many(&dev_kill_list);
 
 	rtnl_unlock();
 	up_write(&pernet_ops_rwsem);
-- 
2.55.0.rc0.799.gd6f94ed593-goog