Here is an update for scsi_debug that utilizes driverfs

support for per driver parameters added in lk 2.5.31

1.62 changes:
  - driverfs support for these options (more to come):
    /driverfs/bus/scsi/drivers/scsi_debug/delay [rw]
    /driverfs/bus/scsi/drivers/scsi_debug/num_devs [r]
    /driverfs/bus/scsi/drivers/scsi_debug/opts [rw]
  - start using some C99
  - fdisk requires EINVAL from unsupported ioctls
    (scsi_debug previously used ENOTTY)

1.61 changes:
  - simulate delayed responses, controlled by
    'scsi_debug_delay'
  - support REPORT LUNS
  - support more MODE SENSE pages
  - [following Doug Ledford's suggestion] do autosense
    (i.e. set Scsi_Cmnd::sense_buffer array appropriately
     when a status of CHECK CONDITION is set)
  - minor driverfs support
  - start adding error injection logic, see
    "scsi_debug_every_nth"

Doug Gilbert

drivers/scsi/scsi_debug.h

 #ifndef _SCSI_DEBUG_H
 
 #include <linux/types.h>
+#include <linux/kdev_t.h>
 
 static int scsi_debug_detect(Scsi_Host_Template *);
+static int scsi_debug_release(struct Scsi_Host *);
 /* static int scsi_debug_command(Scsi_Cmnd *); */
 static int scsi_debug_queuecommand(Scsi_Cmnd *, void (*done) (Scsi_Cmnd *));
-static int scsi_debug_abort(Scsi_Cmnd *);
+static int scsi_debug_ioctl(Scsi_Device *, int, void *);
 static int scsi_debug_biosparam(Disk *, struct block_device *, int[]);
+static int scsi_debug_abort(Scsi_Cmnd *);
 static int scsi_debug_bus_reset(Scsi_Cmnd *);
 static int scsi_debug_device_reset(Scsi_Cmnd *);
 static int scsi_debug_host_reset(Scsi_Cmnd *);
@@ -20,29 +23,29 @@ static const char * scsi_debug_info(struct Scsi_Host *);
 /*
  * This driver is written for the lk 2.5 series
  */
-#define SCSI_DEBUG_CANQUEUE  255
+#define SCSI_DEBUG_CANQUEUE  255 	/* needs to be >= 1 */
 
 #define SCSI_DEBUG_MAX_CMD_LEN 16
 
-#define SCSI_DEBUG_TEMPLATE \
-		   {proc_info:         scsi_debug_proc_info,	\
-		    name:              "SCSI DEBUG",		\
-		    info:              scsi_debug_info,		\
-		    detect:            scsi_debug_detect,	\
-		    release:           scsi_debug_release,	\
-		    ioctl:             scsi_debug_ioctl,	\
-		    queuecommand:      scsi_debug_queuecommand, \
-		    eh_abort_handler:  scsi_debug_abort,	\
-		    eh_bus_reset_handler: scsi_debug_bus_reset,	\
-		    eh_device_reset_handler: scsi_debug_device_reset,	\
-		    eh_host_reset_handler: scsi_debug_host_reset,	\
-		    bios_param:        scsi_debug_biosparam,	\
-		    can_queue:         SCSI_DEBUG_CANQUEUE,	\
-		    this_id:           7,			\
-		    sg_tablesize:      64,			\
-		    cmd_per_lun:       3,			\
-		    unchecked_isa_dma: 0,			\
-		    use_clustering:    ENABLE_CLUSTERING,	\
-}
+static Scsi_Host_Template driver_template = {
+	.proc_info =		scsi_debug_proc_info,
+	.name =			"SCSI DEBUG",
+	.info =			scsi_debug_info,
+	.detect =		scsi_debug_detect,
+	.release =		scsi_debug_release,
+	.ioctl =		scsi_debug_ioctl,
+	.queuecommand =		scsi_debug_queuecommand,
+	.eh_abort_handler =	scsi_debug_abort,
+	.eh_bus_reset_handler = scsi_debug_bus_reset,
+	.eh_device_reset_handler = scsi_debug_device_reset,
+	.eh_host_reset_handler = scsi_debug_host_reset,
+	.bios_param =		scsi_debug_biosparam,
+	.can_queue =		SCSI_DEBUG_CANQUEUE,
+	.this_id =		7,
+	.sg_tablesize =		64,
+	.cmd_per_lun =		3,
+	.unchecked_isa_dma = 	0,
+	.use_clustering = 	ENABLE_CLUSTERING,
+};	/* the name 'driver_template' is used by scsi_module.c */
 
 #endif