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

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Date:	Tue, 07 Jun 2011 10:47:57 -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

Hi Julia,

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.
very interesting! Honestly I hadn't thought much further than what you 
see in my semantic patch. I'd noticed piece of code in the iwlegacy 
driver and wondered what'd happen if I taught myself a little bit about 
cocci :)
>    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;
>
> 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
>
>
>    
There seem to be many variations on the theme to consider... though 
hopefully the compiler optimizes most of these out... For example, in 
sound/soc/codecs/wm8940.c, Jonathan Cameron pointed some code out to me 
that looks like this:

         if (ret)
                 goto error_ret;

error_ret:
         return ret;




As an aside, I added a feature to the script for myself so that I can 
for example write 'make coccicheck M=drivers/net/wireless/' for example 
to focus in on that directory and just run the checks there... I can 
submit a patch for this... though I was wondering if there is already a 
way to do this and I just missed it. The thought was to make it work the 
same way you'd build a module.


Greg

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