From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753260Ab2H3XuZ (ORCPT ); Thu, 30 Aug 2012 19:50:25 -0400 Received: from mail.active-venture.com ([67.228.131.205]:50869 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752954Ab2H3XuY (ORCPT ); Thu, 30 Aug 2012 19:50:24 -0400 X-Originating-IP: 108.223.40.66 Date: Thu, 30 Aug 2012 16:50:36 -0700 From: Guenter Roeck To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Pekka Enberg , Ingo Molnar , "H. Peter Anvin" , Jean Delvare , lm-sensors@lm-sensors.org Subject: Re: [PATCH v2 1/2] linux/kernel.h: Introduce IDIV_ROUND_CLOSEST Message-ID: <20120830235036.GA12543@roeck-us.net> References: <1346171456-29255-1-git-send-email-linux@roeck-us.net> <20120830161532.0db909c9.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120830161532.0db909c9.akpm@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.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 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