On Fri, May 18, 2018 at 06:56:24PM +0200, Christoph Hellwig wrote:
> Manpulating the enable_cnt behind the back of the driver will wreck
> complete havok with the kernel state, so disallow it.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Applied to pci/enumeration for v4.18, thanks!
> ---
> drivers/pci/pci-sysfs.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 366d93af051d..788a200fb2dc 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -288,13 +288,16 @@ static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> - if (!val) {
> - if (pci_is_enabled(pdev))
> - pci_disable_device(pdev);
> - else
> - result = -EIO;
> - } else
> + device_lock(dev);
> + if (dev->driver)
> + result = -EBUSY;
> + else if (val)
> result = pci_enable_device(pdev);
> + else if (pci_is_enabled(pdev))
> + pci_disable_device(pdev);
> + else
> + result = -EIO;
> + device_unlock(dev);
>
> return result < 0 ? result : count;
> }
> --
> 2.17.0
>
