From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: SCSI TMF processing; tag allocation Date: Mon, 15 Nov 2010 12:09:02 -0700 Message-ID: <20101115190901.GB6178@parisc-linux.org> References: <380694.87733.qm@web31812.mail.mud.yahoo.com> <4CE181A8.8050102@interlog.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4CE181A8.8050102@interlog.com> Sender: linux-kernel-owner@vger.kernel.org To: Douglas Gilbert Cc: ltuikov@yahoo.com, Greg KH , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, tj@kernel.org, jens.axboe@oracle.com, James.Bottomley@suse.de List-Id: linux-scsi@vger.kernel.org On Mon, Nov 15, 2010 at 01:53:28PM -0500, Douglas Gilbert wrote: > On the subject of UAS, due to some USB-3 streaming protocol > requirements, three tag values cannot be used by SCSI. They > are 0h, FFFEh and FFFFh. So those available for SCSI tag > use are 1h to FFFDh inclusive. I add 1 to the tag value handed to me by the block layer, and use that as the tag value that I tell the UAS device this command has. So if I ask for 256 tags, I'll hand values 1-257 to the device. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."