From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Jiang Liu To: Bjorn Helgaas , Don Dutile , Yinghai Lu , Greg KH , Kenji Kaneshige Cc: Jiang Liu , Taku Izumi , "Rafael J . Wysocki" , Yijing Wang , Xinwei Hu , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Jiang Liu Subject: [RFC PATCH v1 01/22] PCI: use pci_get_domain_bus_and_slot() to avoid race conditions Date: Wed, 8 Aug 2012 00:10:41 +0800 Message-Id: <1344355862-2726-2-git-send-email-jiang.liu@huawei.com> In-Reply-To: <1344355862-2726-1-git-send-email-jiang.liu@huawei.com> References: <1344355862-2726-1-git-send-email-jiang.liu@huawei.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: There's a typical usage pattern to search a PCI device under a specific PCI bus (domian, busno) as below: struct pci_bus *pci_bus = pci_find_bus(domain, busno); struct pci_dev *pci_dev = pci_get_slot(pci_bus, devfn); The above code has a race window between pci_find_bus() and pci_get_slot() if PCI hotplug operations happen 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. Signed-off-by: Jiang Liu --- arch/ia64/sn/kernel/io_common.c | 4 +--- drivers/gpu/vga/vgaarb.c | 15 +++------------ drivers/pci/hotplug/cpcihp_generic.c | 8 ++------ drivers/pci/iov.c | 8 ++------ drivers/pci/xen-pcifront.c | 10 ++-------- 5 files changed, 10 insertions(+), 35 deletions(-) diff --git a/arch/ia64/sn/kernel/io_common.c b/arch/ia64/sn/kernel/io_common.c index fbb5f2f..8630875 100644 --- a/arch/ia64/sn/kernel/io_common.c +++ b/arch/ia64/sn/kernel/io_common.c @@ -229,7 +229,6 @@ void sn_pci_fixup_slot(struct pci_dev *dev, struct pcidev_info *pcidev_info, { int segment = pci_domain_nr(dev->bus); struct pcibus_bussoft *bs; - struct pci_bus *host_pci_bus; struct pci_dev *host_pci_dev; unsigned int bus_no, devfn; @@ -245,8 +244,7 @@ void sn_pci_fixup_slot(struct pci_dev *dev, struct pcidev_info *pcidev_info, bus_no = (pcidev_info->pdi_slot_host_handle >> 32) & 0xff; devfn = pcidev_info->pdi_slot_host_handle & 0xffffffff; - host_pci_bus = pci_find_bus(segment, bus_no); - host_pci_dev = pci_get_slot(host_pci_bus, devfn); + host_pci_dev = pci_get_domain_bus_and_slot(segment, bus_no, devfn); pcidev_info->host_pci_dev = host_pci_dev; pcidev_info->pdi_linux_pcidev = dev; 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; } diff --git a/drivers/pci/hotplug/cpcihp_generic.c b/drivers/pci/hotplug/cpcihp_generic.c index 81af764..a6a71c4 100644 --- a/drivers/pci/hotplug/cpcihp_generic.c +++ b/drivers/pci/hotplug/cpcihp_generic.c @@ -154,12 +154,8 @@ static int __init cpcihp_generic_init(void) if(!r) return -EBUSY; - bus = pci_find_bus(0, bridge_busnr); - if (!bus) { - err("Invalid bus number %d", bridge_busnr); - return -EINVAL; - } - dev = pci_get_slot(bus, PCI_DEVFN(bridge_slot, 0)); + dev = pci_get_domain_bus_and_slot(0, bridge_busnr, + PCI_DEVFN(bridge_slot, 0)); if(!dev || dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) { err("Invalid bridge device %s", bridge); pci_dev_put(dev); diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 74bbaf8..c7d2969 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -152,15 +152,11 @@ failed1: static void virtfn_remove(struct pci_dev *dev, int id, int reset) { char buf[VIRTFN_ID_LEN]; - struct pci_bus *bus; struct pci_dev *virtfn; struct pci_sriov *iov = dev->sriov; - bus = pci_find_bus(pci_domain_nr(dev->bus), virtfn_bus(dev, id)); - if (!bus) - return; - - virtfn = pci_get_slot(bus, virtfn_devfn(dev, id)); + virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus), + virtfn_bus(dev, id), virtfn_devfn(dev, id)); if (!virtfn) return; diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c index d6cc62c..def8d0b 100644 --- a/drivers/pci/xen-pcifront.c +++ b/drivers/pci/xen-pcifront.c @@ -982,7 +982,6 @@ static int pcifront_detach_devices(struct pcifront_device *pdev) int err = 0; int i, num_devs; unsigned int domain, bus, slot, func; - struct pci_bus *pci_bus; struct pci_dev *pci_dev; char str[64]; @@ -1032,13 +1031,8 @@ static int pcifront_detach_devices(struct pcifront_device *pdev) goto out; } - pci_bus = pci_find_bus(domain, bus); - if (!pci_bus) { - dev_dbg(&pdev->xdev->dev, "Cannot get bus %04x:%02x\n", - domain, bus); - continue; - } - pci_dev = pci_get_slot(pci_bus, PCI_DEVFN(slot, func)); + pci_dev = pci_get_domain_bus_and_slot(domain, bus, + PCI_DEVFN(slot, func)); if (!pci_dev) { dev_dbg(&pdev->xdev->dev, "Cannot get PCI device %04x:%02x:%02x.%d\n", -- 1.7.9.5