From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0C28D1E6DCF; Thu, 30 Jan 2025 14:19:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738246753; cv=none; b=CGNulSSQj0vP1WLWVdmsV/TfKRNktgZeRHqXk8lquLFICvJBelZLkCsfnovCp7Y92acFwR4Lf0tNhS3IKQhpgp9zIf/TSePdEga/V/6QoK95nzovYy5wPjXufc+6S8jFN1/Qe01Kpc7k+61MB4ZPVFdEpLjpjVcfaaldWjFgVrg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738246753; c=relaxed/simple; bh=HS2X6U+qfpdCyhYlTu10pdMjlZjyF8YhIhMstQkJKCc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bvICHY9Cu5jUNrzbrcq9NT4s/Tj+U3stlORbhI64BNVRpkvyIayuz689N47bBdCLl9qX3Ivh89YgJWKUtQQSSJe+gOe/G6p9Oed3ehXYXsmbyos/m/wzfWJXEQdijQluF07BHxWEFi/v/E9C8R2UPTGjS8oto6hZlXcbMBTu6/8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fHgdFEQ2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="fHgdFEQ2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AA22C4CED2; Thu, 30 Jan 2025 14:19:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738246752; bh=HS2X6U+qfpdCyhYlTu10pdMjlZjyF8YhIhMstQkJKCc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fHgdFEQ26uqZi10czaA6ZjqSeDhJa8OQGOI3mnVfilBPJwg56IXBjdQF46vJTdGCK 8C6u2cZ6Ai79HOk6pCWiMxv6pnG3gTtDtN8oDGRFR8BWPLM2B/YKaASm3XzdMapuKE /umj6YZCRdKYFEIZuLfGzaBRBPoJIKf7esvWfj/E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Antoine Tenart , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 56/91] net: add exit_batch_rtnl() method Date: Thu, 30 Jan 2025 15:01:15 +0100 Message-ID: <20250130140135.912017826@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250130140133.662535583@linuxfoundation.org> References: <20250130140133.662535583@linuxfoundation.org> User-Agent: quilt/0.68 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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit fd4f101edbd9f99567ab2adb1f2169579ede7c13 ] Many (struct pernet_operations)->exit_batch() methods have to acquire rtnl. In presence of rtnl mutex pressure, this makes cleanup_net() very slow. This patch adds a new exit_batch_rtnl() method to reduce number of rtnl acquisitions from cleanup_net(). exit_batch_rtnl() handlers are called while rtnl is locked, and devices to be killed can be queued in a list provided as their second argument. A single unregister_netdevice_many() is called right before rtnl is released. exit_batch_rtnl() handlers are called before ->exit() and ->exit_batch() handlers. Signed-off-by: Eric Dumazet Reviewed-by: Antoine Tenart Link: https://lore.kernel.org/r/20240206144313.2050392-2-edumazet@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 46841c7053e6 ("gtp: Use for_each_netdev_rcu() in gtp_genl_dump_pdp().") Signed-off-by: Sasha Levin --- include/net/net_namespace.h | 3 +++ net/core/net_namespace.c | 31 ++++++++++++++++++++++++++++++- 2 files changed, 33 insertions(+), 1 deletion(-) diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 167e390ac9d4e..0d61b452b9082 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -382,6 +382,9 @@ struct pernet_operations { void (*pre_exit)(struct net *net); void (*exit)(struct net *net); void (*exit_batch)(struct list_head *net_exit_list); + /* Following method is called with RTNL held. */ + void (*exit_batch_rtnl)(struct list_head *net_exit_list, + struct list_head *dev_kill_list); unsigned int *id; size_t size; }; diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index c4bcedc06822b..e6585a758edd4 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -325,8 +325,9 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) { /* Must be called with pernet_ops_rwsem held */ const struct pernet_operations *ops, *saved_ops; - int error = 0; LIST_HEAD(net_exit_list); + LIST_HEAD(dev_kill_list); + int error = 0; refcount_set(&net->count, 1); refcount_set(&net->passive, 1); @@ -359,6 +360,15 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) 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); @@ -563,6 +573,7 @@ static void cleanup_net(struct work_struct *work) struct net *net, *tmp, *last; struct llist_node *net_kill_list; 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); @@ -603,6 +614,14 @@ static void cleanup_net(struct work_struct *work) */ synchronize_rcu(); + 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); @@ -1150,7 +1169,17 @@ static void free_exit_list(struct pernet_operations *ops, struct list_head *net_ { ops_pre_exit_list(ops, net_exit_list); synchronize_rcu(); + + if (ops->exit_batch_rtnl) { + LIST_HEAD(dev_kill_list); + + rtnl_lock(); + ops->exit_batch_rtnl(net_exit_list, &dev_kill_list); + unregister_netdevice_many(&dev_kill_list); + rtnl_unlock(); + } ops_exit_list(ops, net_exit_list); + ops_free_list(ops, net_exit_list); } -- 2.39.5