From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH -mm 01/11] add device_dma_parameters structure Date: Wed, 24 Oct 2007 07:33:06 -0400 Message-ID: <471F2D72.1060501@garzik.org> References: <67bb10d9f4e9473ddc84d9839114602c1966f19f.tomof@acm.org> <20071024174021G.tomof@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:60484 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751799AbXJXLdL (ORCPT ); Wed, 24 Oct 2007 07:33:11 -0400 In-Reply-To: <20071024174021G.tomof@acm.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: FUJITA Tomonori Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, James.Bottomley@SteelEye.com, jens.axboe@oracle.com, greg@kroah.com, fujita.tomonori@lab.ntt.co.jp FUJITA Tomonori wrote: > iommu code merges scatter/gather segments without considering a low > level driver's restrictions. The problem is that iommu code can't > access to the limitations because they are in request_queue. > > This patch adds a new structure, device_dma_parameters, including dma > information. A pointer to device_dma_parameters is added to struct > device. > > - there are only max_segment_size and segment_boundary_mask there but > we'll move more dma stuff in struct device (like dma_mask) to struct > device_dma_parameters later. segment_boundary_mask is not supported > yet. > > - new accessors for the dma parameters are added. So we can easily > change where to place struct device_dma_parameters in the future. > > - dma_get_max_seg_size returns 64K if dma_parms in struct device isn't > set up properly. 64K is the default max_segment_size in the block > layer. > > Signed-off-by: FUJITA Tomonori > --- > include/linux/device.h | 11 +++++++++++ > include/linux/dma-mapping.h | 15 +++++++++++++++ > 2 files changed, 26 insertions(+), 0 deletions(-) ACK