Re: [PATCH v6 00/11] PCI: Drop duplicated tracking of a pci_dev's bound driver

Andy Shevchenko
2021-10-13T09:27:41Z

On Wed, Oct 13, 2021 at 2:33 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
> On Mon, Oct 04, 2021 at 02:59:24PM +0200, Uwe Kleine-König wrote:

> I split some of the bigger patches apart so they only touched one
> driver or subsystem at a time. I also updated to_pci_driver() so it
> returns NULL when given NULL, which makes some of the validations
> quite a bit simpler, especially in the PM code in pci-driver.c.

It's a bit unusual. Other to_*_dev() are not NULL-aware IIRC.

Below are some comments as well.

...

> static bool match_id(struct pci_dev *pdev, unsigned short vendor, unsigned short device)
> {
> + struct pci_driver *drv = to_pci_driver(pdev->dev.driver);
> const struct pci_device_id *id;
>
> if (pdev->vendor == vendor && pdev->device == device)
> return true;

> + for (id = drv ? drv->id_table : NULL; id && id->vendor; id++)
> + if (id->vendor == vendor && id->device == device)

> + break;

return true;

> return id && id->vendor;

return false;

> }

...

> + afu_result = err_handler->error_detected(afu_dev,
> + state);

One line?

...

> device_lock(&vf_dev->dev);
> - if (vf_dev->dev.driver) {
> + if (to_pci_driver(vf_dev->dev.driver)) {

Hmm...

...

> + if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0

> + && pci_dev->current_state != PCI_UNKNOWN) {

Can we keep && on the previous line?

> + pci_WARN_ONCE(pci_dev, pci_dev->current_state != prev,
> + "PCI PM: Device state not saved by %pS\n",
> + drv->suspend);
> }

...

> + return drv && drv->resume ?
> + drv->resume(pci_dev) : pci_pm_reenable_device(pci_dev);

One line?

...

> + struct pci_driver *drv = to_pci_driver(dev->dev.driver);
> const struct pci_error_handlers *err_handler =
> - dev->dev.driver ? to_pci_driver(dev->dev.driver)->err_handler : NULL;
> + drv ? drv->err_handler : NULL;

Isn't dev->driver == to_pci_driver(dev->dev.driver)?

...

> + struct pci_driver *drv = to_pci_driver(dev->dev.driver);
> const struct pci_error_handlers *err_handler =
> - dev->dev.driver ? to_pci_driver(dev->dev.driver)->err_handler : NULL;
> + drv ? drv->err_handler : NULL;

Ditto.

...

> device_lock(&dev->dev);
> + pdrv = to_pci_driver(dev->dev.driver);
> if (!pci_dev_set_io_state(dev, state) ||
> - !dev->dev.driver ||
> - !(pdrv = to_pci_driver(dev->dev.driver))->err_handler ||

> + !pdrv ||
> + !pdrv->err_handler ||

One line now?

> !pdrv->err_handler->error_detected) {

Or this and the previous line?

...

> + pdrv = to_pci_driver(dev->dev.driver);
> + if (!pdrv ||
> + !pdrv->err_handler ||
> !pdrv->err_handler->mmio_enabled)
> goto out;

Ditto.

...

> + pdrv = to_pci_driver(dev->dev.driver);
> + if (!pdrv ||
> + !pdrv->err_handler ||
> !pdrv->err_handler->slot_reset)
> goto out;

Ditto.

...

> if (!pci_dev_set_io_state(dev, pci_channel_io_normal) ||
> - !dev->dev.driver ||
> - !(pdrv = to_pci_driver(dev->dev.driver))->err_handler ||
> + !pdrv ||
> + !pdrv->err_handler ||
> !pdrv->err_handler->resume)
> goto out;

Ditto.

> - result = PCI_ERS_RESULT_NONE;
>
> pcidev = pci_get_domain_bus_and_slot(domain, bus, devfn);
> if (!pcidev || !pcidev->dev.driver) {
> dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
> pci_dev_put(pcidev);
> - return result;
> + return PCI_ERS_RESULT_NONE;
> }
> pdrv = to_pci_driver(pcidev->dev.driver);

What about splitting the conditional to two with clear error message
in each and use pci_err() in the second one?

...

> default:
> dev_err(&pdev->xdev->dev,
> - "bad request in aer recovery "
> - "operation!\n");
> + "bad request in AER recovery operation!\n");

Stray change? Or is it in a separate patch in your tree?

--
With Best Regards,
Andy Shevchenko