Re: [PATCH] zfcp: Report FCP LUN to SCSI midlayer

[James Bottomley <James.Bottomley@SteelEye.com>]

On Thu, 2007-06-21 at 18:46 +0200, Stefan Richter wrote:
> For example, the SCSI midlayer H:C:T:L tuple is useless for
> SBP-2-attached devices.  What is useful is the ieee1394_id sysfs
> attribute which we expose as a scsi_device's sysfs attribute.  This
> attribute was something implementation-defined until now, but I changed
> it to the concatenation of target port identifier and logical unit
> identifier for Linux 2.6.22, as per SAM(-4) annex A.  (That change is
> merely an alternative format for the old sbp2 driver and the only format
> for the new fw-sbp2 driver.)
> 
> Or did I miss something and there is already a mechanism for transports
> to expose target/LU identifiers?  So that userland doesn't have to care
> what transport it is, except as far as the details of the identifiers'
> formats are concerned? 

H:C is really mid-layer defined (although I'd like to get rid of C
eventually).  They really correspond to physical enumeration of the HBA
devices.  T (or I) is the one we think could be abstracted and placed
within the gift of the transport, but so far there's been a lot of
debate with few actual concrete proposals.  L is basically defined by
SAM for every transport, but I'm really unsure how it should be
represented in all its SAM specified glory.

James