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

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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

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[PATCH 0/4] GPU-DRM-TILCDC: Fine-tuning for two function  implementations SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-22 10:40 +0200
  [PATCH 2/4] GPU-DRM-TILCDC: Return directly after a failed  kfree_table_init() in tilcdc_convert_slave_node() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-22 10:40 +0200
    Re: [PATCH 2/4] GPU-DRM-TILCDC: Return directly after a failed  kfree_table_init() in tilcdc_convert_slave_node() Dan Carpenter <dan.carpenter@oracle.com> - 2016-09-22 13:00 +0200
    Re: [PATCH 2/4] GPU-DRM-TILCDC: Return directly after a failed  kfree_table_init() in tilcdc_convert_slave_node() Jyri Sarha <jsarha@ti.com> - 2016-09-22 19:00 +0200
      Re: GPU-DRM-TILCDC: Return directly after a failed kfree_table_init()  in tilcdc_convert_slave_node() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-22 20:20 +0200
  [PATCH 3/4] GPU-DRM-TILCDC: Less function calls in  tilcdc_convert_slave_node() after error detection SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-22 10:40 +0200
    Re: [PATCH 3/4] GPU-DRM-TILCDC: Less function calls in  tilcdc_convert_slave_node() after error detection Jyri Sarha <jsarha@ti.com> - 2016-09-22 19:10 +0200
      Re: GPU-DRM-TILCDC: Less function calls in  tilcdc_convert_slave_node() after error detection SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-22 20:40 +0200
        Re: GPU-DRM-TILCDC: Less function calls in  tilcdc_convert_slave_node() after error detection Jyri Sarha <jsarha@ti.com> - 2016-09-22 22:30 +0200
          Re: GPU-DRM-TILCDC: Less function calls in  tilcdc_convert_slave_node() after error detection SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-23 09:40 +0200
            Re: GPU-DRM-TILCDC: Less function calls in  tilcdc_convert_slave_node() after error detection Jyri Sarha <jsarha@ti.com> - 2016-09-23 12:40 +0200
              Re: GPU-DRM-TILCDC: Less function calls in  tilcdc_convert_slave_node() after error detection SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-23 13:00 +0200
        Re: GPU-DRM-TILCDC: Less function calls in tilcdc_convert_slave_node()  after error detection Rob Clark <robdclark@gmail.com> - 2016-09-23 13:00 +0200
          Re: GPU-DRM-TILCDC: Less function calls in  tilcdc_convert_slave_node() after error detection SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-23 13:30 +0200
            Re: GPU-DRM-TILCDC: Less function calls in tilcdc_convert_slave_node()  after error detection Rob Clark <robdclark@gmail.com> - 2016-09-23 13:40 +0200
              Re: GPU-DRM-TILCDC: Less function calls in  tilcdc_convert_slave_node() after error detection SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-23 14:20 +0200
                Re: GPU-DRM-TILCDC: Less function calls in tilcdc_convert_slave_node()  after error detection Rob Clark <robdclark@gmail.com> - 2016-09-23 15:10 +0200
  [PATCH 4/4] GPU-DRM-TILCDC: Delete unnecessary variable  initialisations in tilcdc_convert_slave_node() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-22 10:40 +0200

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