Date:	Fri, 9 Jan 2015 18:58:31 +0100
From:	Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
To:	Arend van Spriel <arend@...adcom.com>
Cc:	Julia Lawall <julia.lawall@...6.fr>,
	Kalle Valo <kvalo@...eaurora.org>,
	Larry Finger <Larry.Finger@...inger.net>,
	Brett Rudley <brudley@...adcom.com>,
	Hante Meuleman <meuleman@...adcom.com>,
	Fabian Frederick <fabf@...net.be>,
	"linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
	brcm80211-dev-list@...adcom.com,
	Network Development <netdev@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] brcm80211: brcmsmac: dma: Remove some unused functions

2015-01-07 9:58 GMT+01:00 Arend van Spriel <arend@...adcom.com>:
> On 01/07/15 07:29, Julia Lawall wrote:
>>
>>
>>
>> On Wed, 7 Jan 2015, Rickard Strandqvist wrote:
>>
>>> 2015-01-05 12:06 GMT+01:00 Arend van Spriel<arend@...adcom.com>:
>>>>
>>>> On 01/05/15 11:49, Kalle Valo wrote:
>>>>>
>>>>>
>>>>> Rickard Strandqvist<rickard_strandqvist@...ctrumdigital.se>   writes:
>>>>>
>>>>>> As I hope you can see I have made some changes regarding the
>>>>>> subject-line. Thought it was an advantage to be able to see which file
>>>>>> I actually removed something from. There seems to be a big focus on
>>>>>> getting right on subject-line right in recent weeks.
>>>>>>
>>>>>> I wonder why there is a script that takes a file name, and respond
>>>>>> with an appropriate subject line?
>>>>
>>>>
>>>>
>>>> Is there a script for this? Anyway, I would say driver name is enough.
>>>> Enough about the subject line ;-) I would like to give some general
>>>> remarks
>>>> as you seem to touch a lot of kernel code. First off, I think it is good
>>>> to
>>>> remove unused stuff. However, I would like some more explanation on your
>>>> methodology apart from "partially found by using a static code analysis
>>>> program". So a cover-letter explaining that would have been nice (maybe
>>>> still is). Things like Kconfig option can affect whether function are
>>>> used
>>>> or not so how did you cover that.
>>>>
>>>> Regards,
>>>> Arend
>>>>
>>>>
>>>>> I don't think you can really automate this as some drivers do this a
>>>>> bit
>>>>> differently. You always need to manually check the commit log.
>>>>>
>>>>>> But ok, I change my script accordingly. Should I submit the patch
>>>>>> again?
>>>>>
>>>>>
>>>>>
>>>>> Yes, please resubmit.
>>>>>
>>>>
>>>
>>> Hi Arend
>>>
>>> Yes, a script that had been excellent, I think!
>>> I have one as part of my git send-email script, until a week ago, it
>>> was enough that I removed the "drivers/" and changed all "/" to ": "
>>> I have now been expanded my sed pipe a lot (tell me if anyone is
>>> interested)
>>> But now I've seen everything from uppercase and [DIR], etc.
>>> So I can not understand how anyone should be able to get the right
>>> name without a good help.
>>>
>>> Sure i like to share how I use cppcheck, but is very hesitant to write
>>> this with each patch mails I send though!
>>>
>>> I run:
>>> cppcheck --force --quiet --enable=all .
>>>
>>> Or a specific file instead of .
>>>
>>> This will include, among other things get a lot of error message such,
>>> +4000 for the kernel.
>>> (style) The function 'xxx' is never used
>>>
>>> For these I made a script that searched through all the files after
>>> the function name (cppcheck missed a few). And save the rest so I go
>>> through them and possibly send patches.
>>
>>
>> I think that the question was about what methodology is cppcheck using to
>> find the given issue.  But probably cppcheck is a black box that does
>> whatever it does, so the user doesn't know what the rationale is.
>
>
> That would have been nice, but I also wanted to know what his subsequent
> steps were to validate the output from cppcheck. I went through some
> cppcheck web pages, but they only elaborate on what is can do and not the
> how. But hey, it is an open-source tool so there is always the code to
> check.
>
>> However, I think you mentioned that cppcheck found only some of the
>> issues.  You could thus describe what was the methodology for finding the
>> other ones.
>
>
> Maybe upon removing an unused function it had a ripple effect on others
> becoming unused as well? Still this is speculating and with this kind of
> cleanup effort all over the place it is better to review the methodology.
>
> Regards,
> Arend
>
>> julia


Hi all

Julia cppcheck is a gpl projekt.
http://sourceforge.net/projects/cppcheck/


Arend
I used cppcheck with all option in the linux root, and then use grep
to pick out what I was interested in.  I agree that there is a lack of
documentation, unfortunately.

More exactly how I have done this is, I searched with grep for the
4000 functions, put the result in a lot of files. These were input to
a script that open a file editor, did a visual overview of all over
the place where the function was found, several of them were used, for
example, directly in asambler code. And in recent times I have also
started doing git blame on the file to see how old the code is.
Then I made the choice to remove or not.

Hope this was clear enough :)


Kind regards
Rickard Strandqvist
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