From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Vesely Subject: Re: [PATCH] [SCSI] scsilun_to_int should ignore the highest 2 bits Date: Thu, 06 Jun 2013 11:46:00 +0200 Message-ID: <51B05A58.1070006@redhat.com> References: <1370506691-22933-1-git-send-email-jvesely@redhat.com> <51B04B68.8080001@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51B04B68.8080001@suse.de> Sender: linux-kernel-owner@vger.kernel.org To: Hannes Reinecke Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, James Bottomley List-Id: linux-scsi@vger.kernel.org On Thu 06 Jun 2013 10:42:16 CEST, Hannes Reinecke wrote: > On 06/06/2013 10:18 AM, Jan Vesely wrote: >> From: Jan Vesely >> >> 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. >> >> CC: James Bottomley >> CC: Dan Williams >> Signed-off-by: Jan Vesely >> --- >> drivers/scsi/scsi_scan.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> 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) >> >> lun = 0; >> for (i = 0; i < sizeof(lun); i += 2) >> - lun = lun | (((scsilun->scsi_lun[i] << 8) | >> + lun = lun | ((((scsilun->scsi_lun[i] & 0x3f) << 8) | >> scsilun->scsi_lun[i + 1]) << (i * 8)); >> return lun; >> } >> > Bzzt. It's not that simple. > > For 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 thanks for your response. I'm concerned with iSCSI. it uses SAM2 LUN addressing scheme, and since I found that comment I did not investigate further. I'll wait for your lun64 patches, thanks again -- Jan Vesely