Re: [PATCH 2/8] video: Provide screen_info_get_pci_dev() to find screen_info's PCI device

[Javier Martinez Canillas <javierm@redhat.com>]

Thomas Zimmermann <tzimmermann@suse.de> writes:

> Hi
>
> Am 29.01.24 um 12:04 schrieb Javier Martinez Canillas:
>> Thomas Zimmermann <tzimmermann@suse.de> writes:
>> 
>>> Add screen_info_get_pci_dev() to find the PCI device of an instance
>>> of screen_info. Does nothing on systems without PCI bus.
>>>
>>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>>> ---
>> 
>> [...]
>> 
>>> +struct pci_dev *screen_info_pci_dev(const struct screen_info *si)
>>> +{
>>> +	struct resource res[SCREEN_INFO_MAX_RESOURCES];
>>> +	size_t i, numres;
>>> +	int ret;
>>> +
>>> +	ret = screen_info_resources(si, res, ARRAY_SIZE(res));
>>> +	if (ret < 0)
>>> +		return ERR_PTR(ret);
>>> +	numres = ret;
>>> +
>> 
>> I would just drop the ret variable and assign the screen_info_resources()
>> return value to numres. I think that makes the code easier to follow.
>
> The value of ret could be an errno code. We would effectively return 
> NULL for errors. And I just noticed that the function docs imply this. 
> But NULL is also a valid value if there is no PCI device. I'd prefer to 
> keep the errno-pointer around.
>

Yes. I meant making numres an int instead of size_t (SCREEN_INFO_MAX_RESOURCES
is only 3 after all). That way you could just return ERR_PTR(numres) if is < 0.

No strong preference, just think that the code is easier to read in that case.

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat