From patchwork Fri Mar 12 15:04:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antoine Tenart X-Patchwork-Id: 12134873 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 894FCC4332D for ; Fri, 12 Mar 2021 15:06:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DBF965011 for ; Fri, 12 Mar 2021 15:06:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232241AbhCLPFq (ORCPT ); Fri, 12 Mar 2021 10:05:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:43784 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232117AbhCLPFS (ORCPT ); Fri, 12 Mar 2021 10:05:18 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 76FA864F77; Fri, 12 Mar 2021 15:05:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615561518; bh=93q1yME4SnPArwRej82dCQACOb9FzkuLHbN6O+/CdeE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FoAqWr3T5pJZEQe7GRfgZc6zpueZcLpw4RqcMKvZrkxl0K7mN5fql2TDU6ZNPyKdd fzU9JEmdPTsvxyqozOyW02fOmgYQaoLzBWVGVpqAlVI2nlH0YSp+q2Y80xeMBfu3+8 NOJhxNmqouoC6PbodJ75hQnX0o4kxKmSNmAbs5reSP2MagZSWAabMiMxIlODNWxQlt CrbblsuiWdCWRbp0EoIe7PWp1bm8F7Kw0ElOHihCi1rBQfcvPcIgn9bJLcO1vdawvi rFVm8YGvzf7WDcM6/iXNbsQ/KzIQEVjJNdIlJEFoOckhwSuWyne1aDK4yxqMmn22I/ fj2ra+PIPAynA== From: Antoine Tenart To: davem@davemloft.net, kuba@kernel.org, alexander.duyck@gmail.com Cc: Antoine Tenart , netdev@vger.kernel.org Subject: [PATCH net-next v3 11/16] net-sysfs: move the rtnl unlock up in the xps show helpers Date: Fri, 12 Mar 2021 16:04:39 +0100 Message-Id: <20210312150444.355207-12-atenart@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210312150444.355207-1-atenart@kernel.org> References: <20210312150444.355207-1-atenart@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Now that nr_ids and num_tc are stored in the xps dev_maps, which are RCU protected, we do not have the need to protect the maps in the rtnl lock. Move the rtnl unlock up so we reduce the rtnl locking section. We also increase the reference count on the subordinate device if any, as we don't want this device to be freed while we use it (now that the rtnl lock isn't protecting it in the whole function). Signed-off-by: Antoine Tenart --- net/core/net-sysfs.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index ca1f3b63cfad..094fea082649 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1383,10 +1383,14 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue, tc = netdev_txq_to_tc(dev, index); if (tc < 0) { - ret = -EINVAL; - goto err_rtnl_unlock; + rtnl_unlock(); + return -EINVAL; } + /* Make sure the subordinate device can't be freed */ + get_device(&dev->dev); + rtnl_unlock(); + rcu_read_lock(); dev_maps = rcu_dereference(dev->xps_maps[XPS_CPUS]); nr_ids = dev_maps ? dev_maps->nr_ids : nr_cpu_ids; @@ -1417,8 +1421,7 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue, } out_no_maps: rcu_read_unlock(); - - rtnl_unlock(); + put_device(&dev->dev); len = bitmap_print_to_pagebuf(false, buf, mask, nr_ids); bitmap_free(mask); @@ -1426,8 +1429,7 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue, err_rcu_unlock: rcu_read_unlock(); -err_rtnl_unlock: - rtnl_unlock(); + put_device(&dev->dev); return ret; } @@ -1486,10 +1488,9 @@ static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) return restart_syscall(); tc = netdev_txq_to_tc(dev, index); - if (tc < 0) { - ret = -EINVAL; - goto err_rtnl_unlock; - } + rtnl_unlock(); + if (tc < 0) + return -EINVAL; rcu_read_lock(); dev_maps = rcu_dereference(dev->xps_maps[XPS_RXQS]); @@ -1522,8 +1523,6 @@ static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) out_no_maps: rcu_read_unlock(); - rtnl_unlock(); - len = bitmap_print_to_pagebuf(false, buf, mask, nr_ids); bitmap_free(mask); @@ -1531,8 +1530,6 @@ static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) err_rcu_unlock: rcu_read_unlock(); -err_rtnl_unlock: - rtnl_unlock(); return ret; }