From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH] [SCSI] scsilun_to_int should ignore the highest 2 bits Date: Thu, 06 Jun 2013 10:42:16 +0200 Message-ID: <51B04B68.8080001@suse.de> References: <1370506691-22933-1-git-send-email-jvesely@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1370506691-22933-1-git-send-email-jvesely@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Jan Vesely Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, James Bottomley , Dan Williams List-Id: linux-scsi@vger.kernel.org On 06/06/2013 10:18 AM, Jan Vesely wrote: > From: Jan Vesely >=20 > The comment says the function does this but it does not. > Reported luns change from weirdly high numbers (like 16640) > to something saner (256), when using flat space addressing. >=20 > CC: James Bottomley > CC: Dan Williams > Signed-off-by: Jan Vesely > --- > drivers/scsi/scsi_scan.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c > index 3e58b22..38dc093 100644 > --- a/drivers/scsi/scsi_scan.c > +++ b/drivers/scsi/scsi_scan.c > @@ -1244,7 +1244,7 @@ int scsilun_to_int(struct scsi_lun *scsilun) > =20 > lun =3D 0; > for (i =3D 0; i < sizeof(lun); i +=3D 2) > - lun =3D lun | (((scsilun->scsi_lun[i] << 8) | > + lun =3D lun | ((((scsilun->scsi_lun[i] & 0x3f) << 8) | > scsilun->scsi_lun[i + 1]) << (i * 8)); > return lun; > } >=20 Bzzt. It's not that simple. =46or SCSI-3 _all_ numbers are valid, and doesn't know of any addressing scheme. It's only SPC-2 which introduced the addressing scheme. So at the very least you should be checking the scsi revision before attempting something like this. But in general doing a sequential scan past 256 is criminally dangerous. Any array / device attempting to is in most cases misconfigured or does not have the correct BLIST flag set. I know of some older Hitachi and EMC firmware which would pretend to be SCSI-2, but supporting more than 256 LUNs per host. Which, of course, it totally bonkers. I'll be posting my 64-bit LUN patchset, that should fix this issue. 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)