netdev - [PATCH v1 net-next 1/3] net: Drop hold_rtnl arg from ops_undo

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Message-ID: <20250415022258.11491-2-kuniyu@amazon.com>
Date: Mon, 14 Apr 2025 19:21:59 -0700
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>
CC: Simon Horman <horms@...nel.org>, Kuniyuki Iwashima <kuniyu@...zon.com>,
	Kuniyuki Iwashima <kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v1 net-next 1/3] net: Drop hold_rtnl arg from ops_undo_list().

ops_undo_list() first iterates over ops_list for ->pre_exit().

Let's check if any of the ops has ->exit_rtnl() there and drop
the hold_rtnl argument.

Note that nexthop uses ->exit_rtnl() and is built-in, so hold_rtnl
is always true for setup_net() and cleanup_net() for now.

Suggested-by: Jakub Kicinski <kuba@...nel.org>
Link: https://lore.kernel.org/netdev/20250414170148.21f3523c@kernel.org/
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
 net/core/net_namespace.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 0a2b24af4028..48dd6dc603c9 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -220,17 +220,20 @@ static void ops_free_list(const struct pernet_operations *ops,
 static void ops_undo_list(const struct list_head *ops_list,
 			  const struct pernet_operations *ops,
 			  struct list_head *net_exit_list,
-			  bool expedite_rcu, bool hold_rtnl)
+			  bool expedite_rcu)
 {
 	const struct pernet_operations *saved_ops;
+	bool hold_rtnl = false;
 
 	if (!ops)
 		ops = list_entry(ops_list, typeof(*ops), list);
 
 	saved_ops = ops;
 
-	list_for_each_entry_continue_reverse(ops, ops_list, list)
+	list_for_each_entry_continue_reverse(ops, ops_list, list) {
+		hold_rtnl |= !!ops->exit_rtnl;
 		ops_pre_exit_list(ops, net_exit_list);
+	}
 
 	/* Another CPU might be rcu-iterating the list, wait for it.
 	 * This needs to be before calling the exit() notifiers, so the
@@ -257,11 +260,10 @@ static void ops_undo_list(const struct list_head *ops_list,
 static void ops_undo_single(struct pernet_operations *ops,
 			    struct list_head *net_exit_list)
 {
-	bool hold_rtnl = !!ops->exit_rtnl;
 	LIST_HEAD(ops_list);
 
 	list_add(&ops->list, &ops_list);
-	ops_undo_list(&ops_list, NULL, net_exit_list, false, hold_rtnl);
+	ops_undo_list(&ops_list, NULL, net_exit_list, false);
 	list_del(&ops->list);
 }
 
@@ -452,7 +454,7 @@ static __net_init int setup_net(struct net *net)
 	 * for the pernet modules whose init functions did not fail.
 	 */
 	list_add(&net->exit_list, &net_exit_list);
-	ops_undo_list(&pernet_list, ops, &net_exit_list, false, true);
+	ops_undo_list(&pernet_list, ops, &net_exit_list, false);
 	rcu_barrier();
 	goto out;
 }
@@ -681,7 +683,7 @@ static void cleanup_net(struct work_struct *work)
 		list_add_tail(&net->exit_list, &net_exit_list);
 	}
 
-	ops_undo_list(&pernet_list, NULL, &net_exit_list, true, true);
+	ops_undo_list(&pernet_list, NULL, &net_exit_list, true);
 
 	up_read(&pernet_ops_rwsem);
 
-- 
2.49.0