Re: [PATCH 09/12] PCI: Add a PCI_ID_F_VFIO_DRIVER_OVERRIDE flag to struct pci_device_id

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Jul 21, 2021 at 07:16:06PM +0300, Yishai Hadas wrote:
> From: Max Gurtovoy <mgurtovoy@nvidia.com>
> 
> The new flag field is be used to allow PCI drivers to signal the core code
> during driver matching and when generating the modules.alias information.
> ...

> @@ -152,10 +152,27 @@ static const struct pci_device_id *pci_match_device(struct pci_driver *drv,
>  	}
>  	spin_unlock(&drv->dynids.lock);
>  
> -	if (!found_id)
> -		found_id = pci_match_id(drv->id_table, dev);
> +	if (found_id)
> +		return found_id;
> +
> +	ids = drv->id_table;
> +	while ((found_id = pci_match_id(ids, dev))) {
> +		/*
> +		 * The match table is split based on driver_override. Check the
> +		 * flags as well so that any matching PCI_ID_F_DRIVER_OVERRIDE
> +		 * entry is returned.
> +		 */
> +		if ((found_id->flags & PCI_ID_F_VFIO_DRIVER_OVERRIDE) &&
> +		    !dev->driver_override)
> +			ids = found_id + 1;
> +		else
> +			break;
> +	}
>  
> -	/* driver_override will always match, send a dummy id */
> +	/*
> +	 * if no static match, driver_override will always match, send a dummy
> +	 * id.
> +	 */
>  	if (!found_id && dev->driver_override)
>  		found_id = &pci_device_id_any;

Possibly more readable:

  while ((found_id = pci_match_id(ids, dev))) {

    /*
     * PCI_ID_F_VFIO_DRIVER_OVERRIDE entries only match when
     * driver_override matches this driver.
     */
    if (found_id->flags & PCI_ID_F_VFIO_DRIVER_OVERRIDE) {
      if (dev->driver_override)
	return found_id;
      else
	ids = found_id + 1;
    } else {
      return found_id;
    }
  }

  /* Driver_override will always match; send a dummy ID */
  if (dev->driver_override)
    return &pci_device_id_any;

  return NULL;