From patchwork Tue Aug 28 15:43:55 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiang Liu X-Patchwork-Id: 1381831 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 6139CDF283 for ; Tue, 28 Aug 2012 15:46:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753176Ab2H1Poj (ORCPT ); Tue, 28 Aug 2012 11:44:39 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:56281 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752900Ab2H1Poh (ORCPT ); Tue, 28 Aug 2012 11:44:37 -0400 Received: by mail-pb0-f46.google.com with SMTP id rr13so9582872pbb.19 for ; Tue, 28 Aug 2012 08:44:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=7+AeisBrGfdXWIlBPPai+MPtE2fqSqcMsgFfzeX6OT4=; b=O+l0WJgxonrzJDXOR+Ky0PdXALBfrHeO8gdKZM4UMYxMUSpw5PiamvkxpF8Q1izylF HSoXdBJ/XfbXFnXRryEGd3PYSXyiE3Gw5ZA+7KRfwjEpD8fkCfvs+KfkqMjpH0EQ2uZ9 KIHdz7NQrsmElHj373vQ00U2LoKWnfIguM+Jq8mMVHYgVzikhP9tWv4AMHlZ1oXFcyjS QweDYQ4cw7yLzO8YDD13UmGOY5MZjJYrSe9cYWoI0hu8/9taCcWpZoKLT5/UlosSkYOR jIQe68Y+BwU65wXPQzVto+LLr99r3pfBWwDZ9u5ezdmKnBkqPM856gZPYn5pbjE8ExcG XIeA== Received: by 10.68.235.236 with SMTP id up12mr43387403pbc.79.1346168677286; Tue, 28 Aug 2012 08:44:37 -0700 (PDT) Received: from localhost.localdomain ([58.250.81.2]) by mx.google.com with ESMTPS id tq4sm17276577pbc.11.2012.08.28.08.44.30 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 28 Aug 2012 08:44:34 -0700 (PDT) From: Jiang Liu To: Bjorn Helgaas , Dave Airlie Cc: Jiang Liu , Don Dutile , Yinghai Lu , Kenji Kaneshige , Yijing Wang , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: [PATCH 2/5] PCI/vga: simplify code by hotplug safe pci_get_domain_bus_and_slot() Date: Tue, 28 Aug 2012 23:43:55 +0800 Message-Id: <1346168638-32724-3-git-send-email-jiang.liu@huawei.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1346168638-32724-1-git-send-email-jiang.liu@huawei.com> References: <1346168638-32724-1-git-send-email-jiang.liu@huawei.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Following code has a race window between pci_find_bus() and pci_get_slot() if PCI hotplug operation happens between them which removes the pci_bus. So use PCI hotplug safe interface pci_get_domain_bus_and_slot() instead, which also reduces code complexity. struct pci_bus *pci_bus = pci_find_bus(domain, busno); struct pci_dev *pci_dev = pci_get_slot(pci_bus, devfn); Signed-off-by: Jiang Liu --- drivers/gpu/vga/vgaarb.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c index 3df8fc0..b6852b7 100644 --- a/drivers/gpu/vga/vgaarb.c +++ b/drivers/gpu/vga/vgaarb.c @@ -1066,7 +1066,6 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf, } } else if (strncmp(curr_pos, "target ", 7) == 0) { - struct pci_bus *pbus; unsigned int domain, bus, devfn; struct vga_device *vgadev; @@ -1085,19 +1084,11 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf, pr_debug("vgaarb: %s ==> %x:%x:%x.%x\n", curr_pos, domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn)); - pbus = pci_find_bus(domain, bus); - pr_debug("vgaarb: pbus %p\n", pbus); - if (pbus == NULL) { - pr_err("vgaarb: invalid PCI domain and/or bus address %x:%x\n", - domain, bus); - ret_val = -ENODEV; - goto done; - } - pdev = pci_get_slot(pbus, devfn); + pdev = pci_get_domain_bus_and_slot(domain, bus, devfn); pr_debug("vgaarb: pdev %p\n", pdev); if (!pdev) { - pr_err("vgaarb: invalid PCI address %x:%x\n", - bus, devfn); + pr_err("vgaarb: invalid PCI address %x:%x:%x\n", + domain, bus, devfn); ret_val = -ENODEV; goto done; }