Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932330AbWCHSf0 (ORCPT ); Wed, 8 Mar 2006 13:35:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932326AbWCHSf0 (ORCPT ); Wed, 8 Mar 2006 13:35:26 -0500 Received: from mx1.redhat.com ([66.187.233.31]:26053 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S932234AbWCHSfZ (ORCPT ); Wed, 8 Mar 2006 13:35:25 -0500 From: David Howells In-Reply-To: <20060308173605.GB13063@devserv.devel.redhat.com> References: <20060308173605.GB13063@devserv.devel.redhat.com> <20060308145506.GA5095@devserv.devel.redhat.com> <31492.1141753245@warthog.cambridge.redhat.com> <29826.1141828678@warthog.cambridge.redhat.com> <9834.1141837491@warthog.cambridge.redhat.com> To: Alan Cox Cc: David Howells , torvalds@osdl.org, akpm@osdl.org, mingo@redhat.com, linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Document Linux's memory barriers [try #2] X-Mailer: MH-E 7.92+cvs; nmh 1.1; GNU Emacs 22.0.50.4 Date: Wed, 08 Mar 2006 18:35:07 +0000 Message-ID: <11922.1141842907@warthog.cambridge.redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 721 Lines: 17 Alan Cox wrote: > spin_unlock ensures that local CPU writes before the lock are visible > to all processors before the lock is dropped but it has no effect on > I/O ordering. Just a need for clarity. So I can't use spinlocks in my driver to make sure two different CPUs don't interfere with each other when trying to communicate with a device because the spinlocks don't guarantee that I/O operations will stay in effect within the locking section? David - 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/