From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH] sg: increase sglist_len of the sg_scatter_hold structure Date: Wed, 8 Aug 2007 09:15:28 +0200 Message-ID: <20070808071528.GJ5245@kernel.dk> References: <46B600F4.7020601@torque.net> <20070806130944R.fujita.tomonori@lab.ntt.co.jp> <46B8A845.4080106@cs.wisc.edu> <20070808073801U.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from brick.kernel.dk ([87.55.233.238]:2796 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765026AbXHHHPb (ORCPT ); Wed, 8 Aug 2007 03:15:31 -0400 Content-Disposition: inline In-Reply-To: <20070808073801U.fujita.tomonori@lab.ntt.co.jp> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: FUJITA Tomonori Cc: michaelc@cs.wisc.edu, dougg@torque.net, tomof@acm.org, linux-scsi@vger.kernel.org, James.Bottomley@SteelEye.com On Wed, Aug 08 2007, FUJITA Tomonori wrote: > Now only scsi-ml is changed to allocate chaining sg list > properly. Others like cciss are not converted yet, I think. It might > make sense to have the standard block layer functions to allocate > chaining sg list properly. So we could convert to potential consumers > (scsi-ml, sg, ccisss, etc) use them though I'm not sure how many non > scsi-ml needs chaining sg list. The scsi chain table allocation/freeing could be made generic. The reason I didn't do that is - as you list - that probably not many non-scsi drivers need/want it. If they do, we can put that functionality in the block layer. The cciss hardware doesn't support more than 31 segments iirc. Newer firmwares can do chaining as well, but the linux driver doesn't actually support it. Once it does, we can add sg chaining support there too. -- Jens Axboe