Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758958Ab2HYAxW (ORCPT ); Fri, 24 Aug 2012 20:53:22 -0400 Received: from mail.active-venture.com ([67.228.131.205]:56344 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754910Ab2HYAxT (ORCPT ); Fri, 24 Aug 2012 20:53:19 -0400 X-Virus-Scan: Scanned by ClamAV 0.97.2 (no viruses); Fri, 24 Aug 2012 19:53:18 -0500 X-Originating-IP: 108.223.40.66 From: Guenter Roeck To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Pekka Enberg , Ingo Molnar , "H. Peter Anvin" , Jean Delvare , lm-sensors@lm-sensors.org, Guenter Roeck Subject: [PATCH] kernel.h: Introduce IDIV_ROUND_CLOSEST Date: Fri, 24 Aug 2012 17:53:17 -0700 Message-Id: <1345855997-9408-1-git-send-email-linux@roeck-us.net> X-Mailer: git-send-email 1.7.9.7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1518 Lines: 48 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 often used on integers which can be negative (such as temperatures). Introduce new macro IDIV_ROUND_CLOSEST which also supports negative dividends. Signed-off-by: Guenter Roeck --- I can take this patch through my hwmon tree, but would like to get an Ack first. Alternative would be to put it into include/linux/hwmon.h, but I would prefer to avoid that. Also, if someone has an idea for a simpler implementation, I would really like to know about it. include/linux/kernel.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 6043821..a89483c 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -89,6 +89,15 @@ } \ ) +#define IDIV_ROUND_CLOSEST(x, divisor)( \ +{ \ + typeof(x) __x = x; \ + typeof(divisor) __d1 = divisor; \ + typeof(divisor) __d2 = (__x) < 0 ? -(__d1) : (__d1);\ + (((__x) + ((__d2) / 2)) / (__d1)); \ +} \ +) + /* * Multiplies an integer by a fraction, while avoiding unnecessary * overflow or loss of precision. -- 1.7.9.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/