On Mon, Jul 20, 2015 at 07:14:54PM -0500, Bjorn Helgaas wrote:
> There's no need to BUG() if we enable ATS when it's already enabled. We
> don't need to BUG() when disabling ATS on a device that doesn't support ATS
> or if it's already disabled. If ATS is enabled, certainly we found an ATS
> capability in the past, so it should still be there now.
>
> Clean up these error paths.
>
> Signed-off-by: Bjorn Helgaas <[email protected]>
> ---
> drivers/pci/ats.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
> index 0b5b0ed..67524a7 100644
> --- a/drivers/pci/ats.c
> +++ b/drivers/pci/ats.c
> @@ -44,11 +44,12 @@ int pci_enable_ats(struct pci_dev *dev, int ps)
> u16 ctrl;
> struct pci_dev *pdev;
>
> - BUG_ON(dev->ats_cap && dev->ats_enabled);
> -
> if (!dev->ats_cap)
> return -EINVAL;
>
> + if (pci_ats_enabled(dev))
> + return -EINVAL;
> +
Better return -EBUSY here? It would be good to find out if we are trying
to enable ATS while it is already enabled. A WARN_ON around this would
also be good, so that we spot bugs in the iommu drivers early when they
use this interface.
Joerg
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