Re: [PATCH v2 04/10] PCI/P2PDMA: Clear ACS P2P flags for all devices behind switches

[Logan Gunthorpe]

On 01/03/18 11:02 AM, Bjorn Helgaas wrote:
> >   void pci_enable_acs(struct pci_dev *dev)
> >   {
> > +	if (pci_p2pdma_disable_acs(dev))
> > +		return;
>
> This doesn't read naturally to me.  I do see that when
> CONFIG_PCI_P2PDMA is not set, pci_p2pdma_disable_acs() does nothing
> and returns 0, so we'll go ahead and try to enable ACS as before.
>
> But I think it would be clearer to have an #ifdef CONFIG_PCI_P2PDMA
> right here so it's more obvious that we only disable ACS when it's
> selected.

I could do this... however, I wrote it this way because I've read Linus 
dislikes using #ifdef's inside function bodies and I personally agree 
with that sentiment.

Logan