Re: [PATCH] [SCSI] scsilun_to_int should ignore the highest 2 bits
From: Jan Vesely
Date: Thu Jun 06 2013 - 05:46:19 EST
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 <jvesely@xxxxxxxxxx>
>> 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 <JBottomley@xxxxxxxxxxxxx>
>> CC: Dan Williams <dan.j.williams@xxxxxxxxx>
>> Signed-off-by: Jan Vesely <jvesely@xxxxxxxxxx>
>> 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.
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,
Jan Vesely <jvesely@xxxxxxxxxx>
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