From patchwork Thu Mar 18 18:37:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antoine Tenart X-Patchwork-Id: 12149011 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 96249C433DB for ; Thu, 18 Mar 2021 18:39:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4CDC164F01 for ; Thu, 18 Mar 2021 18:39:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232632AbhCRSiz (ORCPT ); Thu, 18 Mar 2021 14:38:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:43990 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232694AbhCRSiZ (ORCPT ); Thu, 18 Mar 2021 14:38:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7F22564F69; Thu, 18 Mar 2021 18:38:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616092705; bh=1Sp7cr19Qqp+LzEYvRyL3hXdS3DHoYWAqzJ2dxOmAN4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LtHkGVO2q48Gnl/EUdn3MUuSoh/PMB7/peV2y+pytaHPQodO36Ndv0WLTtDTZhZhZ SGe7+sBnklo4ni12DjQainYDuq4TxULohB6yM+x3wOQcqxb4UuNMb40MMIlzUBgKwM 4bWs3X75gNoc8tqpGTWuJbaJzZq3z5P2+nUkYcqg72aT+ATOW/T6+D3BB2pm9122Hq jvVpAqgDZJpcRu/ExXNZBL1iKLgu9HHJ6AMm5BTtj2hs2IvpXWNnTxwf8eWplnAWNp rDKdMROR5m+ioIowN67Vk+3CHbPccM4JOrnL0gNuWfSfaAUvRBSxH2n+67kGptHo1K FvpJKg0Y/QXBQ== 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 v4 10/13] net-sysfs: move the rtnl unlock up in the xps show helpers Date: Thu, 18 Mar 2021 19:37:49 +0100 Message-Id: <20210318183752.2612563-11-atenart@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210318183752.2612563-1-atenart@kernel.org> References: <20210318183752.2612563-1-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; }