From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753352Ab2H1Pok (ORCPT ); Tue, 28 Aug 2012 11:44:40 -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 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-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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; } -- 1.7.9.5