linux-kernel - Re: [PATCH] coccinelle: if(ret)return ret; return ret; semantic patch

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Date:	Sat, 11 Jun 2011 10:37:14 -0500
From:	Greg Dietsche <gregory.dietsche@....edu>
To:	Julia Lawall <julia@...u.dk>
CC:	Gilles.Muller@...6.fr, npalix.work@...il.com, cocci@...u.dk,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] coccinelle: if(ret)return ret; return ret; semantic patch

On 06/05/2011 11:55 PM, Julia Lawall wrote:
> Thanks.  I tried this too, but I wasn't sure about the results.  The
> question is why stop here.  For example, there are IS_ERR calls that one
> could consider as well.  Or ret<  0.  Or why not just:
>
> @@
> expression ret;
> @@
>
> - if (...) return ret;
>    return ret;
>
>    
I've been thinking a bit more about this. Is there a community 
preference towards patches that are highly reliable v.s. ones that find 
things that might not be a problem? I'm leaning towards updating my 
patch to do the above and then later coming back when I have more time 
to fix it up to find only things that are really problems.

Greg
> Although there might be function calls that one doesn't want to touch, so:
>
> @@
> identifier f != IS_ERR;
> expression ret;
> statement S;
> @@
>
> (
> if (<+...f(...)...+>) S
> |
> - if (...) return ret;
>    return ret;
> )
>
> julia
>
>
> On Sun, 5 Jun 2011, Greg Dietsche wrote:
>
>    
>> This semantic patch finds code matching this pattern:
>> 	if(ret)
>> 		return ret;
>> 	return ret;
>>
>> I will be submitting patches shortly against the mainline to cleanup all
>> code matching this pattern.
>>
>> Signed-off-by: Greg Dietsche<Gregory.Dietsche@....edu>
>> ---
>>   scripts/coccinelle/misc/doublereturn.cocci |   20 ++++++++++++++++++++
>>   1 files changed, 20 insertions(+), 0 deletions(-)
>>   create mode 100644 scripts/coccinelle/misc/doublereturn.cocci
>>
>> diff --git a/scripts/coccinelle/misc/doublereturn.cocci b/scripts/coccinelle/misc/doublereturn.cocci
>> new file mode 100644
>> index 0000000..656a118
>> --- /dev/null
>> +++ b/scripts/coccinelle/misc/doublereturn.cocci
>> @@ -0,0 +1,20 @@
>> +/// Remove unecessary if/return in code that follows this pattern:
>> +///	if(retval)
>> +///		return retval;
>> +///	return retval;
>> +//
>> +// Confidence: High
>> +// Copyright: (C) 2011 Greg Dietsche GPLv2.
>> +// URL: http://www.gregd.org
>> +// Comments:
>> +// Options: -no_includes
>> +
>> +virtual patch
>> +
>> +@@
>> +identifier retval;
>> +@@
>> +-if (retval)
>> +-	return retval;
>> +-return retval;
>> ++return retval;
>> -- 
>> 1.7.2.5
>>
>>
>>      
>    
--
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