linux-kernel - Re: [PATCH v2] staging: rtl8723bs: Use % 4096 instead of & 0xfff

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Message-ID: <CADYq+fbsYFZaS6EiAKPhv5vf9f1_Z6vho-vDENeYwR3=bvR2xg@mail.gmail.com>
Date: Sun, 6 Apr 2025 20:31:43 +0100
From: Samuel Abraham <abrahamadekunle50@...il.com>
To: Julia Lawall <julia.lawall@...ia.fr>
Cc: Andy Shevchenko <andy.shevchenko@...il.com>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, andy@...nel.org, dan.carpenter@...aro.org, 
	linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	outreachy@...ts.linux.dev
Subject: Re: [PATCH v2] staging: rtl8723bs: Use % 4096 instead of & 0xfff

On Sun, Apr 6, 2025 at 1:59 PM Julia Lawall <julia.lawall@...ia.fr> wrote:
>
>
>
> On Sat, 5 Apr 2025, Samuel Abraham wrote:
>
> > On Sat, Apr 5, 2025 at 1:30 PM Julia Lawall <julia.lawall@...ia.fr> wrote:
> > >
> > >
> > >
> > > On Sat, 5 Apr 2025, Andy Shevchenko wrote:
> > >
> > > > On Sat, Apr 5, 2025 at 11:23 AM Greg Kroah-Hartman
> > > > <gregkh@...uxfoundation.org> wrote:
> > > > > On Sat, Apr 05, 2025 at 12:09:59AM +0000, Abraham Samuel Adekunle wrote:
> > > > > > Replace the bitwise AND operator `&` with a modulo
> > > > > > operator `%` and decimal number to make the upper limit visible
> > > > > > and clear what the semantic of it is.
> > > > >
> > > > > Eeek, no.  We all "know" what & means (it's a bit mask to handle the
> > > > > issues involved), and we all do NOT know that % will do the same thing
> > > > > at all.
> > > >
> > > > And that is exactly the purpose of the change. The % 4096 makes it
> > > > clearer on what's going on, i.e. we are doing indexes that are wrapped
> > > > around the given number.
> > >
> > > Ah, OK.  Samuel, indeed, the log message was going in that direction.  But
> > > probably it should be more clear.  Why is 4096 the upper limit in this
> > > case, for example.
> >
> > Okay thank you Julia.
> > So I can add something like this to the commit message?
> >
> > "Replace the bitwise AND operator `&` with a modulo
> > operator `%` and decimal number to make the upper limit visible
> > and clear that we are doing indexes that are wrapped around the given number"?
>
> No.  First say what the upper limit is.  Then explain that a module
> operation is thus more appropriate than a bit mask.  People need to
> understand the reasoning behind the change.  By saying "make the upper
> limit visible" you are asking them to trust your reasoning, or more likely
> requiring them to reconstruct it.  You need to make explicit all the
> information that is needed to understand the change, so people will know
> what to look for to verify it.

Okay thank you very much I get now.
>
> > You also said I should add a patch for the white space around binary operators.
> > I did it together because the changes were on the same line.
> > Should I still add a second patch for that change?
>
> It's quite a different issue.  So, a second patch seems reasonable.  You
> can do it before yours.  Then, if someone still doesn't like the modulo
> patch, the spacing patch can still be accepted.

Okay then.
It makes a lot of sense.
Thank you.

Adekunle