netdev - [PATCH v1 net-next 2/3] ppp: Split ppp_exit_net() to ->exit_batch

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Message-ID: <20250214081818.81658-3-kuniyu@amazon.com>
Date: Fri, 14 Feb 2025 17:18:17 +0900
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller"
	<davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski
	<kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Simon Horman
	<horms@...nel.org>
CC: Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
	<kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v1 net-next 2/3] ppp: Split ppp_exit_net() to ->exit_batch_rtnl().

ppp_exit_net() unregisters devices related to the netns under RTNL and
destroys lists and IDR.

Let's move the device unregistration to ->exit_batch_rtnl() to save RTNL
dances for each netns.

While at it, unregister_netdevice_queue() is replaced with ppp_nl_dellink()
to avoid a potential issue like the one recently found in geneve. [0]

Note that ppp_nl_dellink() is bare unregister_netdevice_queue().

Link: https://lore.kernel.org/netdev/20250213043354.91368-1-kuniyu@amazon.com/ [0]
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
 drivers/net/ppp/ppp_generic.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 4583e15ad03a..560fcc495cd8 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -1134,28 +1134,38 @@ static __net_init int ppp_init_net(struct net *net)
 	return 0;
 }
 
-static __net_exit void ppp_exit_net(struct net *net)
+static void ppp_nl_dellink(struct net_device *dev, struct list_head *head);
+
+static __net_exit void ppp_destroy_links(struct net *net,
+					 struct list_head *dev_kill_list)
 {
 	struct ppp_net *pn = net_generic(net, ppp_net_id);
-	struct net_device *dev;
-	struct net_device *aux;
+	struct net_device *dev, *aux;
 	struct ppp *ppp;
-	LIST_HEAD(list);
 	int id;
 
-	rtnl_lock();
-	for_each_netdev_safe(net, dev, aux) {
+	for_each_netdev_safe(net, dev, aux)
 		if (dev->netdev_ops == &ppp_netdev_ops)
-			unregister_netdevice_queue(dev, &list);
-	}
+			ppp_nl_dellink(dev, dev_kill_list);
 
 	idr_for_each_entry(&pn->units_idr, ppp, id)
 		/* Skip devices already unregistered by previous loop */
 		if (!net_eq(dev_net(ppp->dev), net))
-			unregister_netdevice_queue(ppp->dev, &list);
+			ppp_nl_dellink(ppp->dev, dev_kill_list);
+}
 
-	unregister_netdevice_many(&list);
-	rtnl_unlock();
+static __net_exit void ppp_exit_net_batch_rtnl(struct list_head *net_exit_list,
+					       struct list_head *dev_kill_list)
+{
+	struct net *net;
+
+	list_for_each_entry(net, net_exit_list, exit_list)
+		ppp_destroy_links(net, dev_kill_list);
+}
+
+static __net_exit void ppp_exit_net(struct net *net)
+{
+	struct ppp_net *pn = net_generic(net, ppp_net_id);
 
 	mutex_destroy(&pn->all_ppp_mutex);
 	idr_destroy(&pn->units_idr);
@@ -1165,6 +1175,7 @@ static __net_exit void ppp_exit_net(struct net *net)
 
 static struct pernet_operations ppp_net_ops = {
 	.init = ppp_init_net,
+	.exit_batch_rtnl = ppp_exit_net_batch_rtnl,
 	.exit = ppp_exit_net,
 	.id   = &ppp_net_id,
 	.size = sizeof(struct ppp_net),
-- 
2.39.5 (Apple Git-154)