From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751966AbZCINWq (ORCPT ); Mon, 9 Mar 2009 09:22:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751079AbZCINWi (ORCPT ); Mon, 9 Mar 2009 09:22:38 -0400 Received: from mail.pentek.com ([12.35.250.145]:3551 "HELO mailhost.pentek.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751217AbZCINWi (ORCPT ); Mon, 9 Mar 2009 09:22:38 -0400 X-Greylist: delayed 2644 seconds by postgrey-1.27 at vger.kernel.org; Mon, 09 Mar 2009 09:22:37 EDT Message-ID: <49B50DBE.8020100@pentek.com> Date: Mon, 09 Mar 2009 08:38:22 -0400 From: Steve Rottinger User-Agent: Thunderbird 2.0.0.12 (X11/20080226) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Direct transfer between SCSI and PCI Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi All, I am working with version 2.6.23 of the linux kernel on a custom PowerPC board. As part of my project, I need to be able to directly transfer data from a large buffer that resides on a custom PCI communications device to a SCSI disk without going through the CPU's main memory. Initially, it seemed like opening up the raw SCSI device in O_DIRECT mode would be the perfect solution. However, through some experimentation, and reading some posts from a few years back, it appears that O_DIRECT only works on buffer's that reside in processor's main memory. Does anyone have any suggestions as to how to get this to work? My environment is pretty well controlled, so I can patch/hack the kernel without any problem. Thanks in advance, -Steve