scsi_debug: improve driver description in Kconfig

Try to give a more accurate driver description and some extra
information in less lines.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDouglas Gilbert <dgilbert@interlog.com>
Reviewed-by: NEwan D. Milne <emilne@redhat.com>

drivers/scsi/Kconfig

@@ -1462,18 +1462,17 @@ config SCSI_WD719X
 	  SCSI controllers (based on WD33C296A chip).
 
 config SCSI_DEBUG
-	tristate "SCSI debugging host simulator"
+	tristate "SCSI debugging host and device simulator"
 	depends on SCSI
 	select CRC_T10DIF
 	help
-	  This is a host adapter simulator that can simulate multiple hosts
-	  each with multiple dummy SCSI devices (disks). It defaults to one
-	  host adapter with one dummy SCSI disk. Each dummy disk uses kernel
-	  RAM as storage (i.e. it is a ramdisk). To save space when multiple
-	  dummy disks are simulated, they share the same kernel RAM for 
-	  their storage. See <http://sg.danny.cz/sg/sdebug26.html> for more
-	  information. This driver is primarily of use to those testing the
-	  SCSI and block subsystems. If unsure, say N.
+	  This pseudo driver simulates one or more hosts (SCSI initiators),
+	  each with one or more targets, each with one or more logical units.
+	  Defaults to one of each, creating a small RAM disk device. Many
+	  parameters found in the /sys/bus/pseudo/drivers/scsi_debug
+	  directory can be tweaked at run time.
+	  See <http://sg.danny.cz/sg/sdebug26.html> for more information.
+	  Mainly used for testing and best as a module. If unsure, say N.
 
 config SCSI_MESH
 	tristate "MESH (Power Mac internal SCSI) support"