Re: REPORT LUNS

["Josef Möllers" <josef.moellers@fujitsu-siemens.com>]

Patrick Mansfield wrote:
> 
> On Fri, Jun 13, 2003 at 04:04:48PM +0200, Josef Möllers wrote:
> > Hi,
> >
> > Wile trying to figure out how to ignore non-existing LUNs on RAID
> > devices, I have fallen across an error in scsilun_to_int() where it
> > doesn't behave as the comment suggests and a problematic piece of code
> > in scsi_report_lun_scan().
> >
> > Patch is included.
> 
> If we clear the upper bits (address method, per SAM-3), someone has to
> eventually set them again, and this is not handled today in linux scsi
> core.

The comment said that the upper two bits were ignored which they were
not in the original code, so, apart from fixing the shifts, I also added
the mask to keep the code in sync with the comment. I haven't yet
followed the use of the value thus created.

> > @@ -1027,13 +1027,18 @@
> >        * the header, so start at 1 and go up to and including num_luns.
> >        */
> >       for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
> > +             int j;
> > +
> >               lun = scsilun_to_int(lunp);
> >
> >               /*
> >                * Check if the unused part of lunp is non-zero, and so
> >                * does not fit in lun.
> >                */
> > -             if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
> > +             for (j = sizeof(lun); j < sizeof(struct scsi_lun); j++)
> > +                 if (lunp->scsi_lun[j] != 0)
> > +                     break;
> > +             if (j < sizeof(struct scsi_lun)) {
> >                       int i;
> >
> >                       /*
> 
> What does the above patch fix? It looks like they both check if the last
> four bytes are 0.

It does so, iff sizeof(lun) is 4 and sizeof(struct scsi_lun) is 8.
Perhaps it was more a question of personal taste to change the code so
that it also works for 64 bit ints.

-- 
Josef Möllers (Pinguinpfleger bei FSC)
	If failure had no penalty success would not be a prize
						-- T.  Pratchett
-
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html