On Thu, Apr 23, 2020 at 07:55:17PM +0800, Yicong Yang wrote:
> On 2020/4/19 14:51, Bolarinwa Olayemi Saheed wrote:
> > diff --git a/drivers/pci/access.c b/drivers/pci/access.c
> > index 79c4a2ef269a..451f2b8b2b3c 100644
> > --- a/drivers/pci/access.c
> > +++ b/drivers/pci/access.c
> > @@ -409,7 +409,7 @@ int pcie_capability_read_word(struct pci_dev *dev, int pos, u16 *val)
>
> Maybe provide some comments for the function, to notify the outside
> users to do the error code conversion.
A short function comment about the set of possible return values
wouldn't hurt. We don't have those for pci_read_config_word() and
friends, and there are several pcie_capability_*() functions. I don't
think it's worth repeating the comment for every function, so maybe we
could just extend the existing comment at pcie_capability_read_word().
> BTW, pci_{read, write}_config_*() may also have the issues that
> export the private err code outside. You may want to solve these in
> a series along with this patch.
If you see a specific issue, please point it out.
I looked at pci_read_config_word(), and it can return
PCIBIOS_DEVICE_NOT_FOUND, PCIBIOS_BAD_REGISTER_NUMBER, or the return
value from bus->ops->read().
I looked at all the users of PCIBIOS_*. There's really no interesting
use of any of them except by pcibios_err_to_errno() and
xen_pcibios_err_to_errno(), so I'm not sure it's even worth keeping
them.
But I think it's probably more work to excise all of them than it is
to simply make pci_read_config_word() and pcie_capability_read_word()
return the same set of error values. So I think we should do this
first.
> > *val = 0;
> > if (pos & 1)
> > - return -EINVAL;
> > + return PCIBIOS_BAD_REGISTER_NUMBER;
> >
> > if (pcie_capability_reg_implemented(dev, pos)) {
> > ret = pci_read_config_word(dev, pci_pcie_cap(dev) + pos, val);
> > @@ -444,7 +444,7 @@ int pcie_capability_read_dword(struct pci_dev *dev, int pos, u32 *val)
> >
> > *val = 0;
> > if (pos & 3)
> > - return -EINVAL;
> > + return PCIBIOS_BAD_REGISTER_NUMBER;
> >
> > if (pcie_capability_reg_implemented(dev, pos)) {
> > ret = pci_read_config_dword(dev, pci_pcie_cap(dev) + pos, val);
>
