From: Guenter Roeck <linux@roeck-us.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Pekka Enberg <penberg@kernel.org>,
Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
Jean Delvare <khali@linux-fr.org>,
lm-sensors@lm-sensors.org
Subject: Re: [PATCH v2 1/2] linux/kernel.h: Introduce IDIV_ROUND_CLOSEST
Date: Thu, 30 Aug 2012 16:50:36 -0700 [thread overview]
Message-ID: <20120830235036.GA12543@roeck-us.net> (raw)
In-Reply-To: <20120830161532.0db909c9.akpm@linux-foundation.org>
On Thu, Aug 30, 2012 at 04:15:32PM -0700, Andrew Morton wrote:
> On Tue, 28 Aug 2012 09:30:55 -0700
> Guenter Roeck <linux@roeck-us.net> wrote:
>
> > DIV_ROUND_CLOSEST returns a bad result for negative dividends:
> > DIV_ROUND_CLOSEST(-2, 2) = 0
> >
> > Most of the time this does not matter. However, in the hardware monitoring
> > subsystem, it is sometimes used on integers which can be negative (such as
> > temperatures). Introduce new macro IDIV_ROUND_CLOSEST which also supports
> > negative dividends.
> >
>
> Can't we just fix DIV_ROUND_CLOSEST? That will make it a bit slower
> but it's not exactly a speed demon right now. And fixing
> DIV_ROUND_CLOSEST() might just fix other bugs that we don't know about
> yet.
>
Sure, fine with me. I'll submit a patch. Let's see who starts screaming.
Guenter
prev parent reply other threads:[~2012-08-30 23:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-28 16:30 [PATCH v2 1/2] linux/kernel.h: Introduce IDIV_ROUND_CLOSEST Guenter Roeck
2012-08-28 16:30 ` [PATCH 2/2] hwmon: Use IDIV_ROUND_CLOSEST if the dividend can be negative Guenter Roeck
2012-08-30 23:15 ` [PATCH v2 1/2] linux/kernel.h: Introduce IDIV_ROUND_CLOSEST Andrew Morton
2012-08-30 23:50 ` Guenter Roeck [this message]
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