From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Stanislaw Gruszka <stf_xl@wp.pl>,
Helmut Schaa <helmut.schaa@googlemail.com>,
Kalle Valo <kvalo@kernel.org>
Subject: Re: [PATCH] wifi: rt2x00: use explicitly signed type for clamping
Date: Tue, 18 Oct 2022 14:58:30 -0600 [thread overview]
Message-ID: <CAHmME9qQAqXYR0+K=32otECgrni51Z0c38iO3h1VRM4Xf3o2=Q@mail.gmail.com> (raw)
In-Reply-To: <Y08TQwcY3zL3kGHR@smile.fi.intel.com>
On Tue, Oct 18, 2022 at 2:57 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Tue, Oct 18, 2022 at 02:52:43PM -0600, Jason A. Donenfeld wrote:
> > On Tue, Oct 18, 2022 at 11:40:54PM +0300, Andy Shevchenko wrote:
> > > On Tue, Oct 18, 2022 at 02:27:34PM -0600, Jason A. Donenfeld wrote:
> > > > On some platforms, `char` is unsigned, which makes casting -7 to char
> > > > overflow, which in turn makes the clamping operation bogus. Instead,
> > > > deal with an explicit `s8` type, so that the comparison is always
> > > > signed, and return an s8 result from the function as well. Note that
> > > > this function's result is assigned to a `short`, which is always signed.
> > >
> > > Why not to use short? See my patch I just sent.
> >
> > Trying to have the most minimal change here that doesn't rock the boat.
> > I'm not out to rewrite the driver. I don't know the original author's
> > rationales. This patch here is correct and will generate the same code
> > as before on architectures where it wasn't broken.
> >
> > However, if you want your "change the codegen" patch to be taken
> > seriously, you should probably send it to the wireless maintainers like
> > this one, and they can decide. Personally, I don't really care either
> > way.
>
> I have checked the code paths there and I found no evidence that short can't be
> used. That's why my patch.
Do you have a rationale why you want to change codegen?
Jason
next prev parent reply other threads:[~2022-10-18 20:58 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-18 17:27 [akpm-mm:mm-nonmm-unstable 36/41] include/linux/build_bug.h:16:51: error: negative width in bit-field '<anonymous>' kernel test robot
2022-10-18 20:27 ` [PATCH] wifi: rt2x00: use explicitly signed type for clamping Jason A. Donenfeld
2022-10-18 20:40 ` Andy Shevchenko
2022-10-18 20:52 ` Jason A. Donenfeld
2022-10-18 20:57 ` Andy Shevchenko
2022-10-18 20:58 ` Jason A. Donenfeld [this message]
2022-10-18 21:10 ` Andy Shevchenko
2022-10-19 8:01 ` David Laight
2022-10-18 21:07 ` Andrew Morton
2022-10-19 8:14 ` [PATCH v2] wifi: rt2x00: use explicitly signed or unsigned types Jason A. Donenfeld
2022-10-19 9:00 ` Stanislaw Gruszka
2022-10-19 15:54 ` Jason A. Donenfeld
2022-10-19 15:55 ` [PATCH v3] " Jason A. Donenfeld
2022-10-20 10:29 ` Stanislaw Gruszka
2022-10-20 10:36 ` Kalle Valo
2022-10-21 6:48 ` Kalle Valo
2022-10-21 6:58 ` Kalle Valo
2022-10-21 7:00 ` Kalle Valo
2022-10-19 8:52 ` [PATCH] wifi: rt2x00: use explicitly signed type for clamping Stanislaw Gruszka
2022-10-19 11:04 ` Andy Shevchenko
2022-10-20 10:40 ` Stanislaw Gruszka
2022-10-18 20:40 ` [akpm-mm:mm-nonmm-unstable 36/41] include/linux/build_bug.h:16:51: error: negative width in bit-field '<anonymous>' Andy Shevchenko
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