From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262283AbTKRJqy (ORCPT ); Tue, 18 Nov 2003 04:46:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262129AbTKRJqy (ORCPT ); Tue, 18 Nov 2003 04:46:54 -0500 Received: from pub234.cambridge.redhat.com ([213.86.99.234]:32775 "EHLO phoenix.infradead.org") by vger.kernel.org with ESMTP id S262283AbTKRJqx (ORCPT ); Tue, 18 Nov 2003 04:46:53 -0500 Date: Tue, 18 Nov 2003 09:46:52 +0000 From: Christoph Hellwig To: Guennadi Liakhovetski Cc: linux-kernel@vger.kernel.org Subject: Re: DMA_NONE data_direction in scsi Message-ID: <20031118094651.A14904@infradead.org> Mail-Followup-To: Christoph Hellwig , Guennadi Liakhovetski , linux-kernel@vger.kernel.org References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from g.liakhovetski@gmx.de on Mon, Nov 17, 2003 at 08:25:19PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 17, 2003 at 08:25:19PM +0100, Guennadi Liakhovetski wrote: > While trying to fix tmscsim for 2.6, I've arrived at the Oops below, which > is caused by the BUG_ON() in dma_map_page(). In the backtrace below, > data_direction is set to DMA_BIDIRECTIONAL in sd_revalidate_disk(), > > sreq->sr_data_direction = DMA_BIDIRECTIONAL; > > , but already in sd_spinup_disk() it is reset to DMA_NONE: > > SRpnt->sr_data_direction = DMA_NONE; > > So, the question is: is this the correct behaviour, and, if so - how is > the driver supposed to map this request - which direction to pass to > dma_map_*? DMA_NONE means there's nothing to map.