[PATCH v4 net-next 05/15] geneve: use exit_batch_rtnl() method

[Eric Dumazet <edumazet@google.com>]

exit_batch_rtnl() is called while RTNL is held,
and devices to be unregistered can be queued in the dev_kill_list.

This saves one rtnl_lock()/rtnl_unlock() pair,
and one unregister_netdevice_many() call.

Note: it should be possible to remove the synchronize_net()
call from geneve_sock_release() in a future patch.

v4: move WARN_ON_ONCE(!list_empty(&gn->sock_list))
   into geneve_exit_net(), after devices have been unregistered.
   (Antoine Tenart feedback)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Antoine Tenart <atenart@kernel.org>
---
 drivers/net/geneve.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 32c51c244153bd760b9f58001906c04c8b0f37ff..23e97c2e4f6fcb90a8bbb117d7520397f560f15f 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1900,29 +1900,26 @@ static void geneve_destroy_tunnels(struct net *net, struct list_head *head)
 	}
 }
 
-static void __net_exit geneve_exit_batch_net(struct list_head *net_list)
+static void __net_exit geneve_exit_batch_rtnl(struct list_head *net_list,
+					      struct list_head *dev_to_kill)
 {
 	struct net *net;
-	LIST_HEAD(list);
 
-	rtnl_lock();
 	list_for_each_entry(net, net_list, exit_list)
-		geneve_destroy_tunnels(net, &list);
-
-	/* unregister the devices gathered above */
-	unregister_netdevice_many(&list);
-	rtnl_unlock();
+		geneve_destroy_tunnels(net, dev_to_kill);
+}
 
-	list_for_each_entry(net, net_list, exit_list) {
-		const struct geneve_net *gn = net_generic(net, geneve_net_id);
+static void __net_exit geneve_exit_net(struct net *net)
+{
+	const struct geneve_net *gn = net_generic(net, geneve_net_id);
 
-		WARN_ON_ONCE(!list_empty(&gn->sock_list));
-	}
+	WARN_ON_ONCE(!list_empty(&gn->sock_list));
 }
 
 static struct pernet_operations geneve_net_ops = {
 	.init = geneve_init_net,
-	.exit_batch = geneve_exit_batch_net,
+	.exit_batch_rtnl = geneve_exit_batch_rtnl,
+	.exit = geneve_exit_net,
 	.id   = &geneve_net_id,
 	.size = sizeof(struct geneve_net),
 };
-- 
2.43.0.594.gd9cf4e227d-goog