Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932764AbZACUU2 (ORCPT ); Sat, 3 Jan 2009 15:20:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759647AbZACUUU (ORCPT ); Sat, 3 Jan 2009 15:20:20 -0500 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:34512 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759614AbZACUUT (ORCPT ); Sat, 3 Jan 2009 15:20:19 -0500 Date: Sat, 3 Jan 2009 20:19:55 +0000 From: Alan Cox To: Pavel Machek Cc: kernel list , Andrew Morton , mtk.manpages@gmail.com, rdunlap@xenotime.net, linux-doc@vger.kernel.org Subject: Re: atomics: document that linux expects certain atomic behaviour from unsigned long Message-ID: <20090103201955.186974bb@lxorguk.ukuu.org.uk> In-Reply-To: <20090103124400.GA1572@ucw.cz> References: <20090103124400.GA1572@ucw.cz> X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.12; x86_64-redhat-linux-gnu) Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a Lloegr o'r rhif cofrestru 3798903 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 571 Lines: 16 On Sat, 3 Jan 2009 13:44:00 +0100 Pavel Machek wrote: > Linux relies on unsigned long to behave like atomic for read/write. Actually it isn't that simple and this advice shouldn't be given IMHO. unsigned long is not the same as atomic in several respects including ordering and caching of the result. Alan -- 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/