From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: RFC: SCSI Generic version 4 interface Date: Thu, 7 Dec 2006 09:06:59 +0100 Message-ID: <20061207080657.GX4392@kernel.dk> References: <454FAD72.6040103@torque.net> <45503A3B.5050107@garzik.org> <20061107153147.GV19471@kernel.dk> <20061207170208R.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from brick.kernel.dk ([62.242.22.158]:9475 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031824AbWLGIGH (ORCPT ); Thu, 7 Dec 2006 03:06:07 -0500 Content-Disposition: inline In-Reply-To: <20061207170208R.fujita.tomonori@lab.ntt.co.jp> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: FUJITA Tomonori Cc: jeff@garzik.org, dougg@torque.net, linux-scsi@vger.kernel.org, axboe@suse.de On Thu, Dec 07 2006, FUJITA Tomonori wrote: > From: Jens Axboe > Subject: Re: RFC: SCSI Generic version 4 interface > Date: Tue, 7 Nov 2006 16:31:48 +0100 > > > On Tue, Nov 07 2006, Jeff Garzik wrote: > > > Douglas Gilbert wrote: > > > >I was asked to put together a proposal in May this > > > >year for a new SCSI Generic interface structure. This > > > >is the same structure that is used by the block layer > > > >SG_IO ioctl. A few people have asked whether I had forgotten > > > >that I agreed to write the proposal. So here it is. Those > > > >who have seen it have made comments, some of which have > > > >been incorporated. > > > > > > > >Some shortcomings of the sg version 3 interface are: > > > > - can't handle commands with bidirectional data (either > > > > can the SCSI subsystem at the moment) > > > > - if it was a bit more general it could carry other > > > > request/response protocols (e.g. Task Management > > > > Functions and SMP in Serial Attached SCSI) > > > > - no way of associating a task attribute or task tag > > > > with a SCSI command > > > > > > Why avoid Jens Axboe's bsg? > > > > > > It seems like that is already a good interface for carrying other > > > req/resp protocols. > > > > I don't think Doug is avoiding that (if you are Doug, please do explain > > :-), but rather outlining the next generation command format that bsg > > should support for future use. > > sg4 can be implemented on bsg nicely, I think. But why does the > current bsg support sg3 partially? Do you plan to add the rest of sg3 > (which doesn't work nicely) to bsg? What parts of sg v3 are missing? It's been a while since I implemented that stuff, so I forget if I knowingly left out some features. -- Jens Axboe