Sparse LUN scanning - 2.4.x

[Jim Zajkowski <jamesez@umich.edu>]

Hi there,

We have an Apple Xserve RAID, connected through a FC switch.  The RAID 
has LUN-masking enabled, such that one of our Linux boxes only gets LUN 
1 and not LUN 0.  We're running the 2.4.x kernel series now, since this 
is under a RHEL envinronment.

The problem is this: since LUN 0 does not show up -- specifically, it 
can't read the vendor or model informaton -- the kernel SCSI scan does 
not match with the table to tell the kernel to do sparse LUN 
scanning... so the RAID does not appear.

I can make the RAID show up by injecting a add-single-device to the 
SCSI proc layer.  Trivially patching scsi_scan.c to always do sparse 
scanning works as well.  No hokery with max_scsi_luns or ghost devices 
works.

I'm considering making a patch to add a kernel option to force sparse 
scanning.  Is there a better way?

Thanks in advance,

--Jim

-- 
Jim Zajkowski          OpenPGP 0x21135C3    http://www.jimz.net/pgp.asc
System Administrator  8A9E 1DDF 944D 83C3 AEAB  8F74 8697 A823 2113 5C53
UM Life Sciences Institute