From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: RFC: Move SG_GET_SCSI_ID from sg to scsi Date: Mon, 27 Mar 2006 17:05:56 -0500 Message-ID: <442861C4.7080304@torque.net> References: <440C8E60.6020005@torque.net> <440D9F8E.7050402@s5r6.in-berlin.de> Reply-To: dougg@torque.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from canuck.infradead.org ([205.233.218.70]:13806 "EHLO canuck.infradead.org") by vger.kernel.org with ESMTP id S1751501AbWC0WGN (ORCPT ); Mon, 27 Mar 2006 17:06:13 -0500 In-Reply-To: <440D9F8E.7050402@s5r6.in-berlin.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Stefan Richter Cc: Bodo Eggert <7eggert@gmx.de>, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Stefan Richter wrote: > Douglas Gilbert wrote: > >> In linux there is also a move away from the host_number, >> channel_number, target_identifier and LUN tuple used >> traditionally by many Unix SCSI subsystems (most do not >> have the second component: channel_number). At least the >> LUN is not controversial (as long as it is 8 byte!). The >> target_identifier is actually transport dependent (but >> could just be a simple enumeration). The host_number is >> typically an enumeration over PCI addresses but some >> other type of computer buses (e.g. microchannel) could be >> involved. > > > For some transports, not only the channel but also the Scsi_Host is > meaningless. Such transports deal only with targets and logical units. > This includes all multi-protocol + multi-bus or network infrastructures > such as iSCSI, USB, IEEE 1394. Stefan, I have been reviewing this thread and had one point to add here. The identity of the initiator port is important, at least to a SCSI target that can implement (PERSISTENT) RESERVE on behalf of one of its logical units. So you may need to keep the equivalent of Scsi_Host:this_id somewhere. That is another shortcoming of the tuple: the initiator port isn't there. Doug Gilbert