linux-kernel - Re: [PATCH 5/5] Lib: sort.h: replace int size with size

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Message-ID: <20190331105412.GA9393@kroah.com>
Date:   Sun, 31 Mar 2019 12:54:12 +0200
From:   "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
To:     Andrey Abramov <st5pub@...dex.ru>
Cc:     George Spelvin <lkml@....org>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "ard.biesheuvel@...aro.org" <ard.biesheuvel@...aro.org>,
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Subject: Re: [PATCH 5/5] Lib: sort.h: replace int size with size_t size in
 the swap function

On Sun, Mar 31, 2019 at 10:00:18AM +0300, Andrey Abramov wrote:
> 30.03.2019, 23:17, "George Spelvin" <lkml@....org>:
> > On Sat, 30 Mar 2019 at 19:38:26 +0100 greh k-h wrote;
> >>  On Sat, Mar 30, 2019 at 07:43:53PM +0300, Andrey Abramov wrote:
> >>>  Replace int type with size_t type of the size argument
> >>>  in the swap function, also affect all its dependencies.
> >>
> >>  This says _what_ the patch does, but it gives no clue as to _why_ you
> >>  are doing this. Neither did your 0/5 patch :(
> >>
> >>  Why make this change? Nothing afterward depends on it from what I can
> >>  tell, so why is it needed?
> >
> > It's just a minor cleanup, making things less surprising for future
> > programmers. As I wrote in a comment in my patches, using a signed type
> > for an object size is definitely a wart; ever since C89 it's expected
> > you'd use size_t for the purpose.
> >
> > The connection is that it's a natural consequence of doing a pass over
> > every call site.
> >
> > You're right it could be dropped from the series harmlessly, but it
> > comes from the same work. But it's all of *three* call sites in the kernel
> > which are affected. Surely that's not an unreasonable amount of churn
> > to clean up a wart?
> 
> George Spelvin is absolutely right: "It's just a minor cleanup, making
> things less surprising for future programmers."

Then document it.

> 31.03.2019, 00:51, "George Spelvin" <lkml@....org>:
> > It was so obvious to me that I didn't question it, but you have a
> > good point and I'm sure Andrey can clarify. Thanks for the attention!
> 
> I thought that it is obvious enough (argument called "size" should be
> of type size_t in the 90% of cases).  Should I resend this patch with
> better explanation "why"?

Yes, "int" is a very nice variable for "size", you need to explain why
it is better to use size_t here please.

thanks,

greg k-h