From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Jiang Liu <liuj97@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
Jiang Liu <jiang.liu@huawei.com>, Don Dutile <ddutile@redhat.com>,
Yinghai Lu <yinghai@kernel.org>,
Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
Yijing Wang <wangyijing@huawei.com>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH 5/5] PCI/xen-pcifront: simplify code by hotplug safe pci_get_domain_bus_and_slot()
Date: Tue, 28 Aug 2012 12:59:59 -0400 [thread overview]
Message-ID: <20120828165959.GA23312@localhost.localdomain> (raw)
In-Reply-To: <1346168638-32724-6-git-send-email-jiang.liu@huawei.com>
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.liu@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
>
next prev parent reply other threads:[~2012-08-28 17:00 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-28 15:43 [PATCH 0/5] Simplify code by using hotplug safe pci_get_domain_bus_and_slot() Jiang Liu
2012-08-28 15:43 ` [PATCH 1/5] PCI/IA64: simplify code by " Jiang Liu
2012-08-28 15:43 ` [PATCH 2/5] PCI/vga: " Jiang Liu
2012-08-28 15:43 ` [PATCH 3/5] PCI/cpcihp: " Jiang Liu
2012-08-28 15:43 ` [PATCH 4/5] PCI/IOV: " Jiang Liu
2012-09-20 20:38 ` Yinghai Lu
2012-09-20 23:59 ` Bjorn Helgaas
2012-09-21 0:02 ` Jiang Liu
2012-09-21 1:51 ` Yinghai Lu
2012-09-21 2:56 ` Bjorn Helgaas
2012-09-21 6:22 ` Yinghai Lu
2012-09-21 14:15 ` Don Dutile
2012-09-21 15:11 ` Yinghai Lu
2012-08-28 15:43 ` [PATCH 5/5] PCI/xen-pcifront: " Jiang Liu
2012-08-28 16:59 ` Konrad Rzeszutek Wilk [this message]
2012-08-28 23:56 ` Jiang Liu
2012-09-05 16:29 ` Konrad Rzeszutek Wilk
2012-09-05 20:32 ` Konrad Rzeszutek Wilk
2012-09-17 19:34 ` [PATCH 0/5] Simplify code by using " Bjorn Helgaas
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