Re: RFC: Move SG_GET_SCSI_ID from sg to scsi

[Douglas Gilbert]

Stefan Richter wrote:
> Douglas Gilbert wrote:
> 
>> In linux there is also a move away from the host_number,
>> channel_number, target_identifier and LUN tuple used
>> traditionally by many Unix SCSI subsystems (most do not
>> have the second component: channel_number). At least the
>> LUN is not controversial (as long as it is 8 byte!). The
>> target_identifier is actually transport dependent (but
>> could just be a simple enumeration). The host_number is
>> typically an enumeration over PCI addresses but some
>> other type of computer buses (e.g. microchannel) could be
>> involved.
> 
> 
> For some transports, not only the channel but also the Scsi_Host is
> meaningless. Such transports deal only with targets and logical units.
> This includes all multi-protocol + multi-bus or network infrastructures
> such as iSCSI, USB, IEEE 1394.

Stefan,
I have been reviewing this thread and had one point
to add here.

The identity of the initiator port is important, at
least to a SCSI target that can implement (PERSISTENT)
RESERVE on behalf of one of its logical units.
So you may need to keep the equivalent of Scsi_Host:this_id
somewhere.

That is another shortcoming of the <hctl> tuple: the
initiator port isn't there.

Doug Gilbert
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