Date:	Wed, 10 Oct 2007 20:04:16 +0200
From:	Marcel Siegert <mws@...uxtv.org>
To:	Manu Abraham <abraham.manu@...il.com>
CC:	Mauro Carvalho Chehab <mchehab@...radead.org>,
	video4linux-list@...hat.com, Jiri Slaby <jirislaby@...il.com>,
	daniel@...u.de, linux-kernel@...r.kernel.org, holger@...u.de,
	Alan Cox <alan@...hat.com>,
	v4l-dvb maintainer list <v4l-dvb-maintainer@...uxtv.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [v4l-dvb-maintainer] [PATCH 3/3] V4L: cinergyT2, remove bad	usage
 of ERESTARTSYS

Manu Abraham schrieb:
> Marcel Siegert wrote:
>> Manu Abraham schrieb:
>>> Mauro Carvalho Chehab wrote:
>>>> Em Qua, 2007-10-10 Ã s 11:59 -0400, Alan Cox escreveu:
>>>>> On Wed, Oct 10, 2007 at 12:35:41PM -0300, Mauro Carvalho Chehab wrote:
>>>>>> Em Qua, 2007-10-10 Ã s 00:18 -0400, Michael Krufky escreveu:
>>>>>>> Is this illegal as per kernel codingstyle?
>>>>>> Yes, it is. CodingStyle states:
>>>>> <rant>
>>>>> No.. "Illegal" means prohibited by law. Its merely wrong 8)
>>>>> </rant>
>>>> LOL
>>>>
>>>>>> The proper fix is just to replace the offended code by this:
>>>>>>
>>>>>> err=foo();
>>>>>> if (error)
>>>>>>     goto error;
>>>>> Lots of code uses
>>>>>
>>>>>     if ((err = foo()) < 0)
>>>>>
>>>>> so I would'y worry too much. The split one however clearer and also
>>>>> safer.
>>>> Yes, this is not a severe CodingStyle violation. Still, the above code
>>>> is better than the used one.
>>>>
>>>> Since, on your example, it is clear that the programmer wanted to test
>>>> if the value is less than zero.
>>>> The code:
>>>>
>>>>     if ( (err=foo()) )
>>>>
>>>> should also indicate an operator mistake of using =, instead of ==.
>>>>
>>>> Probably, source code analyzers like Coverity will complain about the
>>>> above.
>>>>
>>>> If not violating CodingStyle, I would rather prefer to code this as:
>>>>     if ( !(err=foo() ) or, even better, using:
>>>>     if ( (err=foo()) != 0)
>>>>
>>>> clearly indicating that it is tested if the value is not zero.
>>>>
>>>> Even being a quite simple issue, I would prefer if Jiri can fix it.
>>>>
>>>
>>> When you have only some few lines of code you can write
>>>
>>>  err = foo()
>>>  if (err) {
>>>   do whatever
>>>  }
>>> doesn't matter ..
>>>
>>> But when you have hell a lot of code, checking error's what you
>>> mention is insane.
>>>
>>> ie,
>>>
>>> if ((err = foo()) expr ) is better.
>>>
>>> http://lkml.org/lkml/2007/2/4/56
>>>
>>> Manu
>>>
>> hi manu,
>>
>> it's not worth discussing this in a way like
>> "i know something from the past and that was a different solution".
>>
> 
> didn't mean to look at it that way, because i had addressed my concerns 
> at that time as well.
> 
>> if you look to other parts in that thread like
>>
>> http://lkml.org/lkml/2007/2/3/150
>>
>> you will see that they came also to a kind of different solution,
>> NOT to use the 1-liner for assignment statements.
>>
>> it's more like a religious/personal discussion how to
>> struct/indent/format code.
>> and, to state my position for clear,
> 
> 
> It is. Sometimes i find such things in CodingStyle to be too silly.
> 
>> if kernel coding style document isnt updated to allow the constructions
>> of code that caused this discussion, we dont have to discuss but follow
>> the rules.
>>
>> anything else on this topic (coding style and it's sense) is to be
>> discussed on kernel ml.
>>
> 
> Marcel, It is on LKML.

i do know manu, but as far as i can see from my fresh 2.6.23,
its not solved or changed in vanilla kernel CodingStyle doc.

so we have to follow actual guidelines _or_ wait until
CodingStyle is accordingly updated.

not more, not less.


regards
marcel

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