Re: [PATCH] scsi: Allow 64-bit LUNs during report lun scan

[Bart Van Assche <bvanassche@acm.org>]

On 02/13/13 20:52, Jeremy Linton wrote:
> On 2/13/2013 9:06 AM, Hannes Reinecke wrote:
>> So add a new flag 'support_64bit_luns' to the scsi host and modify report
>> lun scan to not check for max_luns during scanning if that flag is set.
>> This will get rid of the
>
> 	Along these lines, I don't think the scsilun_to_int() and int_to_scsilun()
> routines are correct for > 2^14  luns. SAM  4.6 defines bits 6,7 of byte zero
> in the LU representation format as the address method. Which when set to 00b
> limits it to 256 luns but the overflow into the bus ID probably works for some
> devices.
>
> 	Those routines should probably select/detect an alternative address method
> for luns > 256.
>
> 	Or am I missing something?

I think the LUN-to-int translation should depend on the LUN addressing 
method supported by the target. SAM-5 defines the following LUN 
addressing methods:
a) peripheral device addressing method;
b) flat space addressing method;
c) logical unit addressing method,
d) extended logical unit addressing method;
e) long extended logical unit addressing method.

scsilun_to_int() does the translation correctly for some of these 
addressing methods but not for all of them.

Bart.