On Tue, Aug 28, 2012 at 11:43:58PM +0800, Jiang Liu wrote:
> 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.
Has this happend in practice? Is this something one can reproduce
by manipulating SysFS and at the same time unplugging the PCI
devices?
>
> 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 <jiang....@huawei.com>
> ---
> drivers/pci/xen-pcifront.c | 10 ++--------
> 1 file changed, 2 insertions(+), 8 deletions(-)
>
> 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
>
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