Current it reads:

		    _3btol(&scsi_sense.pages.rigid_geometry.ncyl_2),

  I think the _2 is superfluous. There is a ncyl member of
rigid_geometry that is a 3 byte integer. This is in an SC_DEBUG, so
might have been missed by someone not running with SCSI debugging
enabled. 
  I've removed the _2 and compiling sun3 kernel. Did I do the right
thing?