Re: [PATCH v2 1/7] PCI: Keep the ACS capability offset in device

[Rajat Jain]

Hi Bjorn,

Thanks for taking a look.

On Mon, Jul 6, 2020 at 8:58 AM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote:
>
> On Mon, Jun 29, 2020 at 09:49:37PM -0700, Rajat Jain wrote:
> > Currently this is being looked up at a number of places. Read and store it
> > once at bootup so that it can be used by all later.
>
> Write the commit log so it is complete even without the subject.
> Right now, you have to read the subject to know what "this" refers to.
>
> The subject is like the title; the log is like the body of an article.
> The title isn't *part* of the article, so the article has to make
> sense all by itself.

Fixed.

>
> > +static void pci_enable_acs(struct pci_dev *dev);
>
> I don't think we need this forward declaration, do we?

We need it unless we move its definition further up in the file:

drivers/pci/pci.c: In function âpci_restore_stateâ:
drivers/pci/pci.c:1551:2: error: implicit declaration of function
âpci_enable_acsâ; did you mean âpci_enable_atsâ?
[-Werror=implicit-function-declaration]
 1551 |  pci_enable_acs(dev);

Do you want me to move it up in the file so that we do not need the
forward declaration?

>
> > @@ -4653,7 +4653,7 @@ static int pci_quirk_intel_spt_pch_acs(struct pci_dev *dev, u16 acs_flags)
> >       if (!pci_quirk_intel_spt_pch_acs_match(dev))
> >               return -ENOTTY;
> >
> > -     pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS);
> > +     pos = dev->acs_cap;
>
> I assume you verified that all these quirks are FINAL quirks, since
> pci_init_capabilities() is called after HEADER quirks.  I'll
> double-check before applying this.

None of these quirks are applied via DECLARE_PCI_FIXUP_*(). All these
quirks are called (directly or indirectly) from either
pci_enable_acs() or pci_acs_enabled(),

EXCEPT

pci_idt_bus_quirk(). That one is called from
pci_bus_read_dev_vendor_id() which should be called only after the
parent bridge has been added and setup correctly.

So it looks all good to me.

Thanks,

Rajat



>
> Bjorn