From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751186AbWFEPem (ORCPT ); Mon, 5 Jun 2006 11:34:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751191AbWFEPel (ORCPT ); Mon, 5 Jun 2006 11:34:41 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:62217 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S1751186AbWFEPel (ORCPT ); Mon, 5 Jun 2006 11:34:41 -0400 Date: Mon, 5 Jun 2006 16:34:20 +0100 From: Russell King To: James Bottomley Cc: Tejun Heo , Jens Axboe , Dave Miller , bzolnier@gmail.com, james.steward@dynamicratings.com, jgarzik@pobox.com, mattjreimer@gmail.com, Guennadi Liakhovetski , lkml , linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org Subject: Re: [PATCHSET] block: fix PIO cache coherency bug, take 2 Message-ID: <20060605153420.GB26666@flint.arm.linux.org.uk> Mail-Followup-To: James Bottomley , Tejun Heo , Jens Axboe , Dave Miller , bzolnier@gmail.com, james.steward@dynamicratings.com, jgarzik@pobox.com, mattjreimer@gmail.com, Guennadi Liakhovetski , lkml , linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org References: <1149392479501-git-send-email-htejun@gmail.com> <20060604204444.GF4484@flint.arm.linux.org.uk> <20060604222347.GG4484@flint.arm.linux.org.uk> <1149517656.3489.15.camel@mulgrave.il.steeleye.com> <20060605144456.GA26666@flint.arm.linux.org.uk> <1149521085.3489.24.camel@mulgrave.il.steeleye.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1149521085.3489.24.camel@mulgrave.il.steeleye.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 05, 2006 at 10:24:44AM -0500, James Bottomley wrote: > On Mon, 2006-06-05 at 15:44 +0100, Russell King wrote: > > Hence I find your comment "There are two cases where devices kmap a > > user page into kernel space and then proceed to read from or write to > > it" to be misleading - at the exact point in time that the device > > driver is manipulating the data in that page, it is not a user page. > > zero copy doesn't quite follow that ownership model. What has zero copy (your reply) got to do with faulting pages into userspace (my message). I'm sorry, I don't understand why you've brought this up. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core