On 4/24/20 12:38 AM, Bjorn Helgaas wrote:
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().
Is enough to adjust the comment on pcie_capability_read_word() to this:
/*
* Note that these accessor functions are only for the "PCI Express
* Capability" (see PCIe spec r3.0, sec 7.8). They do not apply to the
* other "PCI Express Extended Capabilities" (AER, VC, ACS, MFVC, etc.)
*
* On error, this function returns a PCIBIOS_* error code,
* you may want to use pcibios_err_to_errno()(include/linux/pci.h)
* to convert to a non-PCI code
*/
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);
Also, can I just send this as a single patch while we conclude on
pcie_capability_write*() ?
Thank you.
- Saheed
