Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758673AbXERQaS (ORCPT ); Fri, 18 May 2007 12:30:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756470AbXERQaH (ORCPT ); Fri, 18 May 2007 12:30:07 -0400 Received: from mga03.intel.com ([143.182.124.21]:25039 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755767AbXERQaE convert rfc822-to-8bit (ORCPT ); Fri, 18 May 2007 12:30:04 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.14,553,1170662400"; d="scan'208";a="229552057" X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: 2.6.22-rc1-mm1 - s390 vs. md Date: Fri, 18 May 2007 09:30:09 -0700 Message-ID: <0C7297FA1D2D244A9C7F6959C0BF1E5201DEA930@azsmsx413.amr.corp.intel.com> In-Reply-To: <20070518073946.716132f4@gondolin.boeblingen.de.ibm.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: 2.6.22-rc1-mm1 - s390 vs. md Thread-Index: AceZDvTiHuZ9aL/ZSR28JB76mq0OxwAWQT3Q From: "Williams, Dan J" To: "Cornelia Huck" Cc: "Andrew Morton" , , "NeilBrown" , "Martin Schwidefsky" , "linux-s390" X-OriginalArrivalTime: 18 May 2007 16:30:03.0803 (UTC) FILETIME=[C9B4BEB0:01C79969] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1174 Lines: 42 > From: Cornelia Huck [mailto:cornelia.huck@de.ibm.com] > Finer granularity is certainly better here, but I'm not quite sure if > this solves our s390 problem (we don't have dma support). All those > backends should also have a non-dma version... In fact that is already there. Here is the form of async_memcpy for example: ... async_memcpy( ... ) { struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMCPY); struct dma_device *device = chan ? chan->device : NULL; int int_en = callback ? 1 : 0; struct dma_async_tx_descriptor *tx = device ? device->device_prep_dma_memcpy(chan, len, int_en) : NULL; if (tx) { /* run the memcpy asynchronously */ ... } else { /* run the memcpy synchronously */ ... } } When CONFIG_DMA_ENGINE=n async_tx_find_channel takes the form: ... async_tx_find_channel( ... ) { return NULL; } So in the S390 case the entire asynchronous path will be compiled away. -- Dan - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/