From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B8ECC18787A; Sat, 17 Oct 2026 16:14:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792253678; cv=none; b=bhWFsp6Ruztfr1hBgieNufNXGR5sKR6M5WXpWNiJM7WlsEHgAOqAWAUttqSTOXuSfNitC8lYIwAvQiiIxcxXx+iitEvYMq6uN6tQAGDlkau0g2PnbkdgS0EtfdZIqvYjbN+g7qLN2A7PBgrXUN1FE5xhiItiBfaPkATCzmkQ2xo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792253678; c=relaxed/simple; bh=JxiAbLx9ycS05iSGN4dXcdV866zlSegPUyypM6acoCk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lBKn+tPshuf6pkpuvHBg+TlLvin6EB/nocpuJIJDvb72QHWAqHriMrOH8lTceRUhRJk7tt/+7wSUeuKZ3sFkWjiV581gCQMqjLINYZA/D+2Vp6nSKbhbqJyT7hc0wC3LhvUr8Go9NCNc3epBXE4xMWZIvD+6+N6kyMp0vsT1G/I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZnJFF7y8; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ZnJFF7y8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10D221F000C4; Sat, 17 Oct 2026 16:14:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792253677; bh=CjtCB0QlA2xhmd9tj87zagySmfSUsW/4uzw9U8NC7Zo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZnJFF7y8YrSOX6watfGk1ig14PuTirczgTujfqsWkeWZxUqTQIEz+tFwrYakJsOoU G+mMexImjP3/5OdEd3QsP8Dovm5Y9NZt5B9JsJ8R7xPBSVIer5aboFme/PP0XGYZi7 1OZ57Amr0RsKTcpTIoCnkHfBr5I1rjlSry0oQB7U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuniyuki Iwashima , Sabrina Dubroca , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 195/869] net: Factorise setup_net() and cleanup_net(). Date: Sat, 17 Oct 2026 17:50:36 +0200 Message-ID: <20261017160042.056647584@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuniyuki Iwashima [ Upstream commit e333b1c3cf25fca348422c9ad5cc8db40b4243fa ] When we roll back the changes made by struct pernet_operations.init(), we execute mostly identical sequences in three places. * setup_net() * cleanup_net() * free_exit_list() The only difference between the first two is which list and RCU helpers to use. In setup_net(), an ops could fail on the way, so we need to perform a reverse walk from its previous ops in pernet_list. OTOH, in cleanup_net(), we iterate the full list from tail to head. The former passes the failed ops to list_for_each_entry_continue_reverse(). It's tricky, but we can reuse it for the latter if we pass list_entry() of the head node. Also, synchronize_rcu() and synchronize_rcu_expedited() can be easily switched by an argument. Let's factorise the rollback part in setup_net() and cleanup_net(). In the next patch, ops_undo_list() will be reused for free_exit_list(), and then two arguments (ops_list and hold_rtnl) will differ. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Sabrina Dubroca Link: https://patch.msgid.link/20250411205258.63164-2-kuniyu@amazon.com Signed-off-by: Jakub Kicinski Stable-dep-of: 60a25ef8dacb ("wireguard: device: use exit_rtnl callback instead of manual rtnl_lock in pre_exit") Signed-off-by: Sasha Levin --- net/core/net_namespace.c | 106 +++++++++++++++++++-------------------- 1 file changed, 51 insertions(+), 55 deletions(-) diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 613b2b07bad9f..25f84a3764f71 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -189,6 +189,53 @@ 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) +{ + const struct pernet_operations *saved_ops; + + if (!ops) + ops = list_entry(ops_list, typeof(*ops), list); + + saved_ops = ops; + + list_for_each_entry_continue_reverse(ops, ops_list, list) + 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 + * rcu_barrier() after ops_undo_list() isn't sufficient alone. + * Also the pre_exit() and exit() methods need this barrier. + */ + if (expedite_rcu) + synchronize_rcu_expedited(); + else + synchronize_rcu(); + + if (hold_rtnl) { + LIST_HEAD(dev_kill_list); + + ops = saved_ops; + rtnl_lock(); + list_for_each_entry_continue_reverse(ops, ops_list, list) { + if (ops->exit_batch_rtnl) + ops->exit_batch_rtnl(net_exit_list, &dev_kill_list); + } + unregister_netdevice_many(&dev_kill_list); + rtnl_unlock(); + } + + ops = saved_ops; + list_for_each_entry_continue_reverse(ops, ops_list, list) + ops_exit_list(ops, net_exit_list); + + ops = saved_ops; + list_for_each_entry_continue_reverse(ops, ops_list, list) + ops_free_list(ops, net_exit_list); +} + /* should be called with nsid_lock held */ static int alloc_netid(struct net *net, struct net *peer, int reqid) { @@ -349,9 +396,8 @@ static __net_init void preinit_net(struct net *net, struct user_namespace *user_ static __net_init int setup_net(struct net *net) { /* Must be called with pernet_ops_rwsem held */ - const struct pernet_operations *ops, *saved_ops; + const struct pernet_operations *ops; LIST_HEAD(net_exit_list); - LIST_HEAD(dev_kill_list); int error = 0; preempt_disable(); @@ -374,29 +420,7 @@ 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); - saved_ops = ops; - list_for_each_entry_continue_reverse(ops, &pernet_list, list) - ops_pre_exit_list(ops, &net_exit_list); - - synchronize_rcu(); - - ops = saved_ops; - rtnl_lock(); - list_for_each_entry_continue_reverse(ops, &pernet_list, list) { - if (ops->exit_batch_rtnl) - ops->exit_batch_rtnl(&net_exit_list, &dev_kill_list); - } - unregister_netdevice_many(&dev_kill_list); - rtnl_unlock(); - - ops = saved_ops; - list_for_each_entry_continue_reverse(ops, &pernet_list, list) - ops_exit_list(ops, &net_exit_list); - - ops = saved_ops; - list_for_each_entry_continue_reverse(ops, &pernet_list, list) - ops_free_list(ops, &net_exit_list); - + ops_undo_list(&pernet_list, ops, &net_exit_list, false, true); rcu_barrier(); goto out; } @@ -594,11 +618,9 @@ static LLIST_HEAD(cleanup_list); static void cleanup_net(struct work_struct *work) { - const struct pernet_operations *ops; - struct net *net, *tmp, *last; struct llist_node *net_kill_list; + struct net *net, *tmp, *last; LIST_HEAD(net_exit_list); - LIST_HEAD(dev_kill_list); /* Atomically snapshot the list of namespaces to cleanup */ net_kill_list = llist_del_all(&cleanup_list); @@ -627,33 +649,7 @@ static void cleanup_net(struct work_struct *work) list_add_tail(&net->exit_list, &net_exit_list); } - /* Run all of the network namespace pre_exit methods */ - list_for_each_entry_reverse(ops, &pernet_list, list) - 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 rcu_barrier() below isn't sufficient alone. - * Also the pre_exit() and exit() methods need this barrier. - */ - synchronize_rcu_expedited(); - - rtnl_lock(); - list_for_each_entry_reverse(ops, &pernet_list, list) { - if (ops->exit_batch_rtnl) - ops->exit_batch_rtnl(&net_exit_list, &dev_kill_list); - } - unregister_netdevice_many(&dev_kill_list); - rtnl_unlock(); - - /* Run all of the network namespace exit methods */ - list_for_each_entry_reverse(ops, &pernet_list, list) - ops_exit_list(ops, &net_exit_list); - - /* Free the net generic variables */ - list_for_each_entry_reverse(ops, &pernet_list, list) - ops_free_list(ops, &net_exit_list); + ops_undo_list(&pernet_list, NULL, &net_exit_list, true, true); up_read(&pernet_ops_rwsem); -- 2.53.0