Re: [PATCH] PCI/VPD: Add simple sanity check to pci_vpd_size()

[Heiner Kallweit <hkallweit1@gmail.com>]

On 17.09.2021 15:53, Krzysztof Wilczyński wrote:
> Hi Heiner,
> 
> [...]
>> Instead let's add a simple sanity check on the number of found tags.
>> A VPD image conforming to the PCI spec can have max. 4 tags:
>> id string, ro section, rw section, end tag.
> 
> It's always nice to check if something is compliant with the specification.
> 
> Would you be able to either cite this part of the official specification or
> mention where to find it?  Like we do in other such changes related to some
> official standards, mainly for posterity to benefit others that might look
> at this commit in the future.
> 
Right, I should have mentioned that:
PCI 3.0 I.3.1. VPD Large and Small Resource Data Tags

> [...]
>> +		/* We can have max 4 tags: STRING_ID, RO, RW, END */
>> +		if (++num_tags > 4)
>> +			goto error;
> 
> Do we want to let someone know that their device (or a device they might
> have in the system) has non-compliant and/or malformed VPD which is why we
> decided to return an error?  I wonder if this would help with
> troubleshooting or just simply had some informative value.  So perhaps
> a warning or debug level message?  What do you think?
> 
A message is printed, see code after error label.  We differentiate
between "hard" and "soft" error. Soft error here means that the VPD EEPROM
is optional, in such a case it's not an actual error that the VPD reads
return non-VPD data.

> Reviewed-by: Krzysztof Wilczyński <kw@linux.com>
> 
> 	Krzysztof
>