Re: scsi_scan_target and SCSI_2

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

On Thu, 2003-11-27 at 07:19, Krishna Murthy wrote:
> scsi_probe_and_add_lun() calls scsi_probe_lun(). In case there is no lun 0
> then the information about scsi_level is lost.

SAM-3 in section 4.9.2 begins "All SCSI devices shall accept LUN 0 as a
valid address...".

This requirement is in SCSI-2 as well.

If your implementation doesn't do this, I suggest you fix it.

If lun 0 responds (as it is required by the standards to do), but shows
only a perfunctory standards conforming response indicating it's not
really present, we scan, and the scsi_level will be recorded for each
correctly scanned lun.

> We now call scsi_sequential_lun_scan() with BLIST_SPARSELUN,SCSI_2 as 
> parameters, which instead should have been bflags,scsi_level as determined by 
> scsi_probe_lun.
> 
> Isn't this is  a bug? Please let me know if I am missing something.

No, it's deliberate.  Whether we should do this is open to debate, but
there's a comment in the code explaining the logic:

		/*
		 * There's a target here, but lun 0 is offline so we
		 * can't use the report_lun scan.  Fall back to a
		 * sequential lun scan with a bflags of SPARSELUN and
		 * a default scsi level of SCSI_2
		 */

James