From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [RFC]: 64 bit LUN/Tags, dummy device in host_queue, host_lock <-> LLDD reentrancy Date: Mon, 26 Aug 2002 11:48:06 -0500 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <200208261648.g7QGm6b00427@localhost.localdomain> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: (from root@localhost) by pogo.mtv1.steeleye.com (8.9.3/8.9.3) id JAA14877 for ; Mon, 26 Aug 2002 09:48:18 -0700 In-Reply-To: Message from "Aron Zeh" of "Mon, 26 Aug 2002 18:29:51 +0200." List-Id: linux-scsi@vger.kernel.org To: Aron Zeh Cc: James Bottomley , Luben Tuikov , linux-scsi ARZEH@de.ibm.com said: > Does the use of driverfs-names mean that the HBA driver somehow comes > into the discovery-loop for devices (e.g. scan_scsis somehow interacts > with the HBA driver to determine which driverfs entry to create.)? Well, scanning is really only for legacy. Way into the future, I'd like to see hotplug notification for device attach events, so no fibre controller ever need be troubled by the scan. All they'd do is send a device attach notification into SCSI when they detect one. (SCSI would probably then turn around and ask for a REPORT_LUNS). > Shouldn't there be some sort of rule for LUN (or unit) naming within > at least the same hardware class? That is for: parallel, iSCSI, FC, > etc. Will the SCSI stack automatically try to discover all devices > behind the HBA (e.g, on the FC SAN)? Or will there be an interface to > restrict the range, etc? Yes, there should. But such a rule would only be for maintaining consistency within driverfs, and therefore could happily become Patric Mochel's problem. If we go the whole hotplug route, discovery would be up to the scsi hotplug scripts. > Lastly, how will you keep track of LUNs in the SCSI stack? Will the > current LUN field disappear in favour of a generic character string? Internally to Scsi_Device, LUNs will be linked by pointers. How we know whether such a linkage needs to occur, I'm not yet sure about. In the worst case we could use driverfs matching to see if a newly discovered device's PUN matches an existing device, or there might be a way for the HBA driver to supply the information. James