From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [Bug 80711] [PATCH]SG_FLAG_LUN_INHIBIT is no longer implemented and there's not way to prevent the kernel from using the 2nd cdb byte for the LUN Date: Thu, 21 Aug 2014 14:57:44 -0700 Message-ID: <20140821215744.GA29651@infradead.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from bombadil.infradead.org ([198.137.202.9]:57636 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754997AbaHUV54 (ORCPT ); Thu, 21 Aug 2014 17:57:56 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Martin K. Petersen" Cc: Alan Stern , Christoph Hellwig , Douglas Gilbert , Tiziano Bacocco , bugzilla-daemon@bugzilla.kernel.org, SCSI development list , USB list On Thu, Aug 21, 2014 at 05:43:41PM -0400, Martin K. Petersen wrote: > Alan> Okay, here's a patch that implements the suggestion, except that I > Alan> put the flag in the Scsi_Host structure instead of the template. > Alan> This was to minimize the impact of the change. Among the various > Alan> SCSI-over-USB transports, only the Bulk-Only transport gives the > Alan> LUN separately from the CDB. I don't know if there are any > Alan> multi-LUN USB devices that don't use the Bulk-Only transport, but > Alan> if there are then they won't work if the LUN isn't stored in > Alan> CDB[1]. > > I'm in agreement with this approach. I like it too. One idea to unclutter the fastpath would be to have a single flag that controls if the LUN is set which is based on the host(-template) flag and the scsi level, which would allow us to remove all the clutter around that area.