#ifndef BSG_H
  #define BSG_H

  #include <linux/types.h>

  #define BSG_PROTOCOL_SCSI		0
  
  #define BSG_SUB_PROTOCOL_SCSI_CMD	0
  #define BSG_SUB_PROTOCOL_SCSI_TMF	1
  #define BSG_SUB_PROTOCOL_SCSI_TRANSPORT	2

  /*
   * For flags member below
   * sg.h sg_io_hdr also has bits defined for it's flags member. However
   * none of these bits are implemented/used by bsg. The bits below are
   * allocated to not conflict with sg.h ones anyway.
   */
  #define BSG_FLAG_Q_AT_TAIL 0x10 /* default, == 0 at this bit, is Q_AT_HEAD */

  struct sg_io_v4 {

  	__s32 guard;		/* [i] 'Q' to differentiate from v3 */
  	__u32 protocol;		/* [i] 0 -> SCSI , .... */
  	__u32 subprotocol;	/* [i] 0 -> SCSI command, 1 -> SCSI task

  				   management function, .... */

  	__u32 request_len;	/* [i] in bytes */
  	__u64 request;		/* [i], [*i] {SCSI: cdb} */

  	__u64 request_tag;	/* [i] {SCSI: task tag (only if flagged)} */

  	__u32 request_attr;	/* [i] {SCSI: task attribute} */

  	__u32 request_priority;	/* [i] {SCSI: task priority} */

  	__u32 request_extra;	/* [i] {spare, for padding} */

  	__u32 max_response_len;	/* [i] in bytes */
  	__u64 response;		/* [i], [*o] {SCSI: (auto)sense data} */

          /* "dout_": data out (to device); "din_": data in (from device) */
  	__u32 dout_iovec_count;	/* [i] 0 -> "flat" dout transfer else
  				   dout_xfer points to array of iovec */

  	__u32 dout_xfer_len;	/* [i] bytes to be transferred to device */

  	__u32 din_iovec_count;	/* [i] 0 -> "flat" din transfer */

  	__u32 din_xfer_len;	/* [i] bytes to be transferred from device */
  	__u64 dout_xferp;	/* [i], [*i] */
  	__u64 din_xferp;	/* [i], [*o] */

  	__u32 timeout;		/* [i] units: millisecond */
  	__u32 flags;		/* [i] bit mask */
  	__u64 usr_ptr;		/* [i->o] unused internally */
  	__u32 spare_in;		/* [i] */

  	__u32 driver_status;	/* [o] 0 -> ok */
  	__u32 transport_status;	/* [o] 0 -> ok */
  	__u32 device_status;	/* [o] {SCSI: command completion status} */
  	__u32 retry_delay;	/* [o] {SCSI: status auxiliary information} */
  	__u32 info;		/* [o] additional information */
  	__u32 duration;		/* [o] time to complete, in milliseconds */
  	__u32 response_len;	/* [o] bytes of response actually written */

  	__s32 din_resid;	/* [o] din_xfer_len - actual_din_xfer_len */
  	__s32 dout_resid;	/* [o] dout_xfer_len - actual_dout_xfer_len */
  	__u64 generated_tag;	/* [o] {SCSI: transport generated task tag} */

  	__u32 spare_out;	/* [o] */

  	__u32 padding;

  };
  
  #ifdef __KERNEL__

  #if defined(CONFIG_BLK_DEV_BSG)
  struct bsg_class_device {

  	struct device *class_dev;

  	struct device *parent;

  	int minor;

  	struct request_queue *queue;

  	struct kref ref;
  	void (*release)(struct device *);

  };

  extern int bsg_register_queue(struct request_queue *q,
  			      struct device *parent, const char *name,
  			      void (*release)(struct device *));

  extern void bsg_unregister_queue(struct request_queue *);

  #else

  static inline int bsg_register_queue(struct request_queue *q,
  				     struct device *parent, const char *name,
  				     void (*release)(struct device *))

  {
  	return 0;
  }

  static inline void bsg_unregister_queue(struct request_queue *q)

  {
  }

  #endif

  #endif /* __KERNEL__ */

  #endif