From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755674AbZFEO6h (ORCPT ); Fri, 5 Jun 2009 10:58:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752571AbZFEO62 (ORCPT ); Fri, 5 Jun 2009 10:58:28 -0400 Received: from moutng.kundenserver.de ([212.227.126.186]:58736 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751798AbZFEO60 (ORCPT ); Fri, 5 Jun 2009 10:58:26 -0400 From: Arnd Bergmann To: FUJITA Tomonori Subject: Re: [PATCH] dma-debug: disable DMA_API_DEBUG for now Date: Fri, 5 Jun 2009 15:57:56 +0100 User-Agent: KMail/1.11.90 (Linux/2.6.30-5-generic; KDE/4.2.85; x86_64; ; ) Cc: joerg.roedel@amd.com, torvalds@linux-foundation.org, mingo@elte.hu, lethal@linux-sh.org, just.for.lkml@googlemail.com, hancockrwd@gmail.com, jens.axboe@oracle.com, bharrosh@panasas.com, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org References: <20090605173232N.fujita.tomonori@lab.ntt.co.jp> <20090605104132.GE24836@amd.com> <20090605203753K.fujita.tomonori@lab.ntt.co.jp> In-Reply-To: <20090605203753K.fujita.tomonori@lab.ntt.co.jp> X-Face: I@=L^?./?$U,EK.)V[4*>`zSqm0>65YtkOe>TFD'!aw?7OVv#~5xd\s,[~w]-J!)|%=]> =?utf-8?q?+=0A=09=7EohchhkRGW=3F=7C6=5FqTmkd=5Ft=3FLZC=23Q-=60=2E=60Y=2Ea=5E?= =?utf-8?q?3zb?=) =?utf-8?q?+U-JVN=5DWT=25cw=23=5BYo0=267C=26bL12wWGlZi=0A=09=7EJ=3B=5Cwg?= =?utf-8?q?=3B3zRnz?=,J"CT_)=\H'1/{?SR7GDu?WIopm.HaBG=QYj"NZD_[zrM\Gip^U MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200906051557.58809.arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX1+6kQ6tG4rJPGcpOc1MkTZtJ2dNWecJQYqEQZ+ gBcQr2g7zlfgHx2+hlBqeriXHhpjy2mfLLS+kvM3IJ2u+IvtY9 91jkH9e7xoKAewzxOxUFg== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 05 June 2009, FUJITA Tomonori wrote: > I think that the better fix can handle both cases per device: > > - multiple identical dma addresses should not happen (with devices > behind hardware IOMMU) > - multiple identical dma addresses could happen I guess you could also have the case where for a given range of addresses, you use a linear mapping and the dma addresses can be identical, while for other physical addresses you would rely on address translation. For example on PowerPC/Cell with infiniband adapters, you can get linear mapping behavior for DMA_ATTR_WEAK_ORDERING but IOMMU translation without that flag, for the same device and same physical address. Arnd <><