Re: GPU-DRM-TILCDC: Less function calls in tilcdc_convert_slave_node() after error detection

Jyri Sarha
2016-09-22T20:23:08Z

On 09/22/16 21:38, SF Markus Elfring wrote:
>>> The of_node_put() function was called in some cases
>>> by the tilcdc_convert_slave_node() function during error handling
>>> even if the passed variable contained a null pointer.
>>>
>>> * Adjust jump targets according to the Linux coding style convention.
>>>
>>> * Split a condition check for resource detection failures so that
>>> each pointer from these function calls will be checked immediately.
>>>
>>> See also background information:
>>> Topic "CWE-754: Improper check for unusual or exceptional conditions"
>>> Link: https://cwe.mitre.org/data/definitions/754.html
>>>
>>
>> I don't really agree with this patch.
>
> This kind of feedback can be fine at first glance.
>
>
>> There is no harm in calling of_node_put() with NULL as an argument
>
> The cost of additional function calls will be eventually not noticed
> just because they belong to an exception handling implementation so far.
>
>
>> and because of that there is no point in making the function more complex
>
> There is inherent software complexity involved.
>

I think the "if (node)" in the of_node_put() is there on purpose,
because it potentially saves the caller one extra if()-statement and
keeps the caller code simpler.

>
>> and harder to maintain.
>
> How do you think about to discuss this aspect a bit more?
>

Keeping the goto labels in right order needs precision and can lead to
subtle errors. Sometimes there is no way to avoid that, but here there is.

Best regards,
Jyri