Re: [Xen-devel] [PATCH V3 1/2] Drivers/PCI: Export pcie_has_flr() interface

Bjorn Helgaas
2017-12-15T00:24:39Z

On Thu, Dec 14, 2017 at 04:52:06AM -0800, Christoph Hellwig wrote:
> On Wed, Dec 13, 2017 at 03:24:21PM -0600, Bjorn Helgaas wrote:
> > Prior to a60a2b73ba69, we had
> >
> > int pcie_flr(struct pci_dev *dev, int probe);
> >
> > like all the other reset methods. AFAICT, the addition of
> > pcie_has_flr() was to optimize the path slightly because when drivers
> > call pcie_flr(), they should already know that their hardware supports
> > FLR. But I don't think that optimization is worth the extra code
> > complexity. If we do need to optimize it, we can check this in the
> > core during enumeration and set PCI_DEV_FLAGS_NO_FLR_RESET
> > accordingly.
> >
> > Christoph, chime in if I'm missing something here.
>
> Didn't we just have that discussion in another thread a few days
> ago?

Probably, but I didn't have a clear picture of what you were suggesting.

> I think that the pcie_has_flr was a mistake in retrospective but I
> think the bool probe API was an even bigger mistake. The only use
> of it is to hide the reset attribute in sysfs. I'd much rather always
> have it and have it return EOPNOTSUPP if no reset method is supported.
>
> I can send a patch for that if it sounds fine to you.

If you can get rid of the whole probe infrastructure, that sounds
good to me.

Bjorn