From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759063AbXLTTIT (ORCPT ); Thu, 20 Dec 2007 14:08:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757262AbXLTTIK (ORCPT ); Thu, 20 Dec 2007 14:08:10 -0500 Received: from relay2.sgi.com ([192.48.171.30]:44152 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750902AbXLTTIJ (ORCPT ); Thu, 20 Dec 2007 14:08:09 -0500 From: akepner@sgi.com Date: Thu, 20 Dec 2007 11:06:42 -0800 To: Stefan Richter Cc: Andrew Morton , grundler@parisc-linux.org, jbarnes@virtuousgeek.org, jes@sgi.com, randy.dunlap@oracle.com, rdreier@cisco.com, James.Bottomley@steeleye.com, davem@davemloft.net, linux-kernel@vger.kernel.org Subject: Re: [RFC] dma: passing "attributes" to dma_map_* routines Message-ID: <20071220190642.GM412@sgi.com> References: <20071218001758.GO21916@sgi.com> <4767FA62.9060002@s5r6.in-berlin.de> <20071218200759.GE412@sgi.com> <476834AC.9050401@s5r6.in-berlin.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <476834AC.9050401@s5r6.in-berlin.de> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 18, 2007 at 09:59:24PM +0100, Stefan Richter wrote: > > From its purpose it sounds like you need this only for few special > memory regions which would typically be mapped by dma_map_single() We need the _sg versions too, as Roland already mentioned. > .... and > furthermore that drivers who need this behavior will be changed to > explicitly demand it. If so, a nonintrusive API extension could simply > be to add an > > dma_addr_t dma_map_single_write_last(struct device *dev, void *ptr, > size_t size, enum dma_data_direction direction); > ... This is the easiest thing to do, and therefore it'd be my preference. But I'm concerned that the keepers of the dma interface will object to this. So far they've been silent in this thread - maybe they need to see a patch before they'll get engaged.... -- Arthur