usb-storage: support for more than 8 LUNs

This is necessary to make some storage arrays work.

Some storage devices have more than 8 LUNs. In addition
you can hook up a WideSCSI bus to USB. In these cases even
level 2 devices can have more than 8 LUNs. For them
it is necessary to simply believe the class specific
command and report its result back to the SCSI layer.

Off by one Alan noticed is fixed.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/storage/usb.c

@@ -889,6 +889,12 @@ static void usb_stor_scan_dwork(struct work_struct *work)
 	    !(us->fflags & US_FL_SCM_MULT_TARG)) {
 		mutex_lock(&us->dev_mutex);
 		us->max_lun = usb_stor_Bulk_max_lun(us);
+		/*
+		 * Allow proper scanning of devices that present more than 8 LUNs
+		 * While not affecting other devices that may need the previous behavior
+		 */
+		if (us->max_lun >= 8)
+			us_to_host(us)->max_lun = us->max_lun+1;
 		mutex_unlock(&us->dev_mutex);
 	}
 	scsi_scan_host(us_to_host(us));