From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH] scsi: Allow 64-bit LUNs during report lun scan Date: Fri, 15 Feb 2013 08:26:31 +0100 Message-ID: <511DE327.4050008@suse.de> References: <1360767971-947-1-git-send-email-hare@suse.de> <511BEF0B.4020302@tributary.com> <1360813101.2502.8.camel@dabdike> <511D26B4.6070302@tributary.com> <94D0CD8314A33A4D9D801C0FE68B402950D58E9A@G9W0745.americas.hpqcorp.net> <511D68CA.6050203@tributary.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from cantor2.suse.de ([195.135.220.15]:42578 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935388Ab3BOH0c (ORCPT ); Fri, 15 Feb 2013 02:26:32 -0500 In-Reply-To: <511D68CA.6050203@tributary.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jeremy Linton Cc: "Elliott, Robert (Server Storage)" , James Bottomley , "linux-scsi@vger.kernel.org" On 02/14/2013 11:44 PM, Jeremy Linton wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 2/14/2013 4:04 PM, Elliott, Robert (Server Storage) wrote: >> Like James notes, LUNs should generally be treated as opaque values. > > Maybe another issue to consider is how they are being displayed in u= serland. > A device with two luns using one of the alternative lun addressing me= thods is > going to get some pretty strange looking lun numbers showing up in us= erspace > if they aren't decoded properly. > No. LUNs with anything other than peripheral addressing do look=20 weird even nowadays. Cf IBM DS8000 presents me with LUNs like: # lsscsi [0:0:0:49409]wlun IBM 2107900 .107 - [0:0:0:1085358099]disk IBM 2107900 .107 /dev/sda where the second maps to LUN 401340b100000000. Again, the initiator _must not_ attempt to decode the LUN. To stick with the above example, LUN 400040b100000000 and LUN 40b1000000000000 do refer to the same LUN number, albeit on a=20 different Level. And it's totally up to the target which physical=20 LUN these numbers refer to. The initiator has to map these numbers=20 to different devices; to figure out whether the devices are=20 identical one would have to look at VPD page 0x83. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: J. Hawn, J. Guild, F. Imend=F6rffer, HRB 16746 (AG N=FCrnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html