From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: [PATCH] sg: increase sglist_len of the sg_scatter_hold structure Date: Wed, 08 Aug 2007 12:20:43 -0500 Message-ID: <46B9FB6B.70501@cs.wisc.edu> References: <46B600F4.7020601@torque.net> <20070806130944R.fujita.tomonori@lab.ntt.co.jp> <46B8A845.4080106@cs.wisc.edu> <20070808073801U.fujita.tomonori@lab.ntt.co.jp> <46B9F626.9020200@cs.wisc.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from sabe.cs.wisc.edu ([128.105.6.20]:44669 "EHLO sabe.cs.wisc.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937466AbXHHRVq (ORCPT ); Wed, 8 Aug 2007 13:21:46 -0400 In-Reply-To: <46B9F626.9020200@cs.wisc.edu> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: FUJITA Tomonori Cc: dougg@torque.net, tomof@acm.org, linux-scsi@vger.kernel.org, James.Bottomley@SteelEye.com, jens.axboe@oracle.com Mike Christie wrote: > For drivers like sg and st, do mean the the sg list that is passed to > functions like scsi_execute_async? If we kill that argument, and instead > have sg.c and other scsi_execute_async callers just call blk helpers > like blk_rq_map_user then we would not have to worry about drivers like > sg needing to know about chaining right? I mean sg.c would not every > interact with a scatterlist. It would just interact with a request and > the blk helpers map data for it. There should be a return there. The scatterlist that sg and st interact > with is bogus. It gets thrown away in scsi_execute_async and is only > used for book keeping. I mean currently the scatterlist that sg and st use is bogus and gets thrown away. If we convert sg and st to use blk_rq_map_user then those drivers will not have to interact with a scatterlist at all.