From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753975Ab0C2WSh (ORCPT ); Mon, 29 Mar 2010 18:18:37 -0400 Received: from mail.perches.com ([173.55.12.10]:1240 "EHLO mail.perches.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751156Ab0C2WSg (ORCPT ); Mon, 29 Mar 2010 18:18:36 -0400 Subject: [PATCH V2] kernel.h: Convert rounding macros to statement expressions, add ADD_MOD From: Joe Perches To: Randy Dunlap Cc: Jiri Kosina , Andrew Morton , LKML In-Reply-To: <20100329144924.d00f0680.randy.dunlap@oracle.com> References: <1269813447.1500.69.camel@Joe-Laptop.home> <20100329124708.898b617c.randy.dunlap@oracle.com> <1269892842.4558.7.camel@Joe-Laptop.home> <1269896989.4558.18.camel@Joe-Laptop.home> <20100329144924.d00f0680.randy.dunlap@oracle.com> Content-Type: text/plain; charset="UTF-8" Date: Mon, 29 Mar 2010 15:18:34 -0700 Message-ID: <1269901114.4558.47.camel@Joe-Laptop.home> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2010-03-29 at 14:49 -0700, Randy Dunlap wrote: > > Do you prefer something like this? > Yes, thanks. > > +#define roundup(x, y) \ > > +({ \ > > + typeof(y) _y = y; \ > > + ((x) + (_y - 1) / _y) * _y; \ > Above needs an extra set of parens: > (((x) + (_y - 1)) / _y) * _y; \ Thanks. I think it's clearer matched to the DIV_ROUND_UP style: (((x) + _y - 1) / _y) * _y; ---------------- Convert rounding macros to statement expressions so arguments are only evaluated once. Add kernel-doc to rounding macros Add ADD_MOD statement expression for "(x + y) % y" Signed-off-by: Joe Perches Reviewed-by: Randy Dunlap --- include/linux/kernel.h | 66 +++++++++++++++++++++++++++++++++++++++++------ 1 files changed, 57 insertions(+), 9 deletions(-) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index c96b1ac..029db3b 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -55,15 +55,63 @@ extern const char linux_proc_banner[]; #define round_down(x, y) ((x) & ~__round_mask(x, y)) #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f)) -#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) -#define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y)) -#define DIV_ROUND_CLOSEST(x, divisor)( \ -{ \ - typeof(divisor) __divisor = divisor; \ - (((x) + ((__divisor) / 2)) / (__divisor)); \ -} \ -) -#define ADD_MOD(x, y) (((x) + (y)) % (y)) + +/** + * roundup() - Returns x rounded up to the next whole multiple of y + * @x: dividend + * @y: divisor + * + * ie: roundup(4, 2) is 4, roundup(5, 2) is 6 + * c type conversion rules apply when x and y types differ + */ +#define roundup(x, y) \ +({ \ + typeof(y) _y = y; \ + (((x) + _y - 1) / _y) * _y; \ +}) + +/** + * DIV_ROUND_UP() - Returns x/y rounded up to the next whole number + * @x: dividend + * @y: divisor + * + * ie: DIV_ROUND_UP(4, 2) is 2, DIV_ROUND_UP(5, 2) is 3 + * c type conversion rules apply when x and y types differ + */ +#define DIV_ROUND_UP(x, y) \ +({ \ + typeof(y) _y = y; \ + ((x) + _y - 1) / _y; \ +}) + +/** + * DIV_ROUND_CLOSEST() - Returns x/y rounded to the nearest whole number + * @x: dividend + * @y: divisor + * + * ie: DIV_ROUND_CLOSEST(4, 3) is 1, DIV_ROUND_CLOSEST(5, 3) is 2 + * Rounds up when .5, ie: DIV_ROUND_CLOSEST(5, 2) is 3 + * c type conversion rules apply when x and y types differ + */ +#define DIV_ROUND_CLOSEST(x, y) \ +({ \ + typeof(y) _y = y; \ + ((x) + (_y / 2)) / _y; \ +}) + +/** + * ADD_MOD() - Returns (x + y) % y + * @x: initial value + * @y: value added to x then used as modulo + * + * ie: ADD_MOD(4, 2) is 0, ADD_MOD(5, 2) is 1 + * c type conversion rules apply when x and y types differ + */ +#define ADD_MOD(x, y) \ +({ \ + typeof(y) _y = y; \ + ((x) + _y) % _y; \ +}) #define _RET_IP_ (unsigned long)__builtin_return_address(0) #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })