text: #ifndef _SCSI_SCSI_DEVICE_H
  #define _SCSI_SCSI_DEVICE_H
  
  #include <linux/device.h>
  #include <linux/list.h>
  #include <linux/spinlock.h>
  #include <linux/workqueue.h>
  #include <linux/blkdev.h>
  #include <asm/atomic.h>
  
  struct request_queue;
  struct scsi_cmnd;
  struct scsi_lun;
  struct scsi_sense_hdr;
  
  struct scsi_mode_data {
  	__u32	length;
  	__u16	block_descriptor_length;
  	__u8	medium_type;
  	__u8	device_specific;
  	__u8	header_length;
  	__u8	longlba:1;
  };
  
  /*
   * sdev state: If you alter this, you also need to alter scsi_sysfs.c
   * (for the ascii descriptions) and the state model enforcer:
   * scsi_lib:scsi_device_set_state().
   */
  enum scsi_device_state {
  	SDEV_CREATED = 1,	/* device created but not added to sysfs
  				 * Only internal commands allowed (for inq) */
  	SDEV_RUNNING,		/* device properly configured
  				 * All commands allowed */
  	SDEV_CANCEL,		/* beginning to delete device
  				 * Only error handler commands allowed */
  	SDEV_DEL,		/* device deleted 
  				 * no commands allowed */
  	SDEV_QUIESCE,		/* Device quiescent.  No block commands
  				 * will be accepted, only specials (which
  				 * originate in the mid-layer) */
  	SDEV_OFFLINE,		/* Device offlined (by error handling or
  				 * user request */
  	SDEV_BLOCK,		/* Device blocked by scsi lld.  No scsi 
  				 * commands from user or midlayer should be issued
  				 * to the scsi lld. */
  };
  
  struct scsi_device {
  	struct Scsi_Host *host;
  	struct request_queue *request_queue;
  
  	/* the next two are protected by the host->host_lock */
  	struct list_head    siblings;   /* list of all devices on this host */
  	struct list_head    same_target_siblings; /* just the devices sharing same target id */
  
  	/* this is now protected by the request_queue->queue_lock */
  	unsigned int device_busy;	/* commands actually active on
  					 * low-level. protected by queue_lock. */
  	spinlock_t list_lock;
  	struct list_head cmd_list;	/* queue of in use SCSI Command structures */
  	struct list_head starved_entry;
  	struct scsi_cmnd *current_cmnd;	/* currently active command */
  	unsigned short queue_depth;	/* How deep of a queue we want */
  	unsigned short last_queue_full_depth; /* These two are used by */
  	unsigned short last_queue_full_count; /* scsi_track_queue_full() */
  	unsigned long last_queue_full_time;/* don't let QUEUE_FULLs on the same
  					   jiffie count on our counter, they
  					   could all be from the same event. */
  
  	unsigned int id, lun, channel;
  
  	unsigned int manufacturer;	/* Manufacturer of device, for using 
  					 * vendor-specific cmd's */
  	unsigned sector_size;	/* size in bytes */
  
  	void *hostdata;		/* available to low-level driver */
  	char type;
  	char scsi_level;
  	char inq_periph_qual;	/* PQ from INQUIRY data */	
  	unsigned char inquiry_len;	/* valid bytes in 'inquiry' */
  	unsigned char * inquiry;	/* INQUIRY response data */
  	const char * vendor;		/* [back_compat] point into 'inquiry' ... */
  	const char * model;		/* ... after scan; point to static string */
  	const char * rev;		/* ... "nullnullnullnull" before scan */
  	unsigned char current_tag;	/* current tag */
  	struct scsi_target      *sdev_target;   /* used only for single_lun */
  
  	unsigned int	sdev_bflags; /* black/white flags as also found in
  				 * scsi_devinfo.[hc]. For now used only to
  				 * pass settings from slave_alloc to scsi
  				 * core. */
  	unsigned writeable:1;
  	unsigned removable:1;
  	unsigned changed:1;	/* Data invalid due to media change */
  	unsigned busy:1;	/* Used to prevent races */
  	unsigned lockable:1;	/* Able to prevent media removal */
  	unsigned locked:1;      /* Media removal disabled */
  	unsigned borken:1;	/* Tell the Seagate driver to be 
  				 * painfully slow on this device */
  	unsigned disconnect:1;	/* can disconnect */
  	unsigned soft_reset:1;	/* Uses soft reset option */
  	unsigned sdtr:1;	/* Device supports SDTR messages */
  	unsigned wdtr:1;	/* Device supports WDTR messages */
  	unsigned ppr:1;		/* Device supports PPR messages */
  	unsigned tagged_supported:1;	/* Supports SCSI-II tagged queuing */
  	unsigned simple_tags:1;	/* simple queue tag messages are enabled */
  	unsigned ordered_tags:1;/* ordered queue tag messages are enabled */
  	unsigned single_lun:1;	/* Indicates we should only allow I/O to
  				 * one of the luns for the device at a 
  				 * time. */
  	unsigned was_reset:1;	/* There was a bus reset on the bus for 
  				 * this device */
  	unsigned expecting_cc_ua:1; /* Expecting a CHECK_CONDITION/UNIT_ATTN
  				     * because we did a bus reset. */
  	unsigned use_10_for_rw:1; /* first try 10-byte read / write */
  	unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
  	unsigned skip_ms_page_8:1;	/* do not use MODE SENSE page 0x08 */
  	unsigned skip_ms_page_3f:1;	/* do not use MODE SENSE page 0x3f */
  	unsigned use_192_bytes_for_3f:1; /* ask for 192 bytes from page 0x3f */
  	unsigned no_start_on_add:1;	/* do not issue start on add */
  	unsigned allow_restart:1; /* issue START_UNIT in error handler */
  	unsigned manage_start_stop:1;	/* Let HLD (sd) manage start/stop */
  	unsigned no_uld_attach:1; /* disable connecting to upper level drivers */
  	unsigned select_no_atn:1;
  	unsigned fix_capacity:1;	/* READ_CAPACITY is too high by 1 */
  	unsigned guess_capacity:1;	/* READ_CAPACITY might be too high by 1 */
  	unsigned retry_hwerror:1;	/* Retry HARDWARE_ERROR */
  	unsigned last_sector_bug:1;	/* do not use multisector accesses on
  					   SD_LAST_BUGGY_SECTORS */
  
  	unsigned int device_blocked;	/* Device returned QUEUE_FULL. */
  
  	unsigned int max_device_blocked; /* what device_blocked counts down from  */
  #define SCSI_DEFAULT_DEVICE_BLOCKED	3
  
  	atomic_t iorequest_cnt;
  	atomic_t iodone_cnt;
  	atomic_t ioerr_cnt;
  
  	int timeout;
  
  	struct device		sdev_gendev;
  	struct class_device	sdev_classdev;
  
  	struct execute_work	ew; /* used to get process context on put */
  
  	enum scsi_device_state sdev_state;
  	unsigned long		sdev_data[0];
  } __attribute__((aligned(sizeof(unsigned long))));
  #define	to_scsi_device(d)	\
  	container_of(d, struct scsi_device, sdev_gendev)
  #define	class_to_sdev(d)	\
  	container_of(d, struct scsi_device, sdev_classdev)
  #define transport_class_to_sdev(class_dev) \
  	to_scsi_device(class_dev->dev)
  
  #define sdev_printk(prefix, sdev, fmt, a...)	\
  	dev_printk(prefix, &(sdev)->sdev_gendev, fmt, ##a)
  
  #define scmd_printk(prefix, scmd, fmt, a...)				\
          (scmd)->request->rq_disk ?					\
  	sdev_printk(prefix, (scmd)->device, "[%s] " fmt,		\
  		    (scmd)->request->rq_disk->disk_name, ##a) :		\
  	sdev_printk(prefix, (scmd)->device, fmt, ##a)
  
  enum scsi_target_state {
  	STARGET_RUNNING = 1,
  	STARGET_DEL,
  };
  
  /*
   * scsi_target: representation of a scsi target, for now, this is only
   * used for single_lun devices. If no one has active IO to the target,
   * starget_sdev_user is NULL, else it points to the active sdev.
   */
  struct scsi_target {
  	struct scsi_device	*starget_sdev_user;
  	struct list_head	siblings;
  	struct list_head	devices;
  	struct device		dev;
  	unsigned int		reap_ref; /* protected by the host lock */
  	unsigned int		channel;
  	unsigned int		id; /* target id ... replace
  				     * scsi_device.id eventually */
  	unsigned int		create:1; /* signal that it needs to be added */
  	unsigned int		pdt_1f_for_no_lun;	/* PDT = 0x1f */
  						/* means no lun present */
  
  	char			scsi_level;
  	struct execute_work	ew;
  	enum scsi_target_state	state;
  	void 			*hostdata; /* available to low-level driver */
  	unsigned long		starget_data[0]; /* for the transport */
  	/* starget_data must be the last element!!!! */
  } __attribute__((aligned(sizeof(unsigned long))));
  
  #define to_scsi_target(d)	container_of(d, struct scsi_target, dev)
  static inline struct scsi_target *scsi_target(struct scsi_device *sdev)
  {
  	return to_scsi_target(sdev->sdev_gendev.parent);
  }
  #define transport_class_to_starget(class_dev) \
  	to_scsi_target(class_dev->dev)
  
  #define starget_printk(prefix, starget, fmt, a...)	\
  	dev_printk(prefix, &(starget)->dev, fmt, ##a)
  
  extern struct scsi_device *__scsi_add_device(struct Scsi_Host *,
  		uint, uint, uint, void *hostdata);
  extern int scsi_add_device(struct Scsi_Host *host, uint channel,
  			   uint target, uint lun);
  extern void scsi_remove_device(struct scsi_device *);
  extern int scsi_device_cancel(struct scsi_device *, int);
  
  extern int scsi_device_get(struct scsi_device *);
  extern void scsi_device_put(struct scsi_device *);
  extern struct scsi_device *scsi_device_lookup(struct Scsi_Host *,
  					      uint, uint, uint);
  extern struct scsi_device *__scsi_device_lookup(struct Scsi_Host *,
  						uint, uint, uint);
  extern struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *,
  							uint);
  extern struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *,
  							  uint);
  extern void starget_for_each_device(struct scsi_target *, void *,
  		     void (*fn)(struct scsi_device *, void *));
  
  /* only exposed to implement shost_for_each_device */
  extern struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *,
  						  struct scsi_device *);
  
  /**
   * shost_for_each_device - iterate over all devices of a host
   * @sdev: the &struct scsi_device to use as a cursor
   * @shost: the &struct scsi_host to iterate over
   *
   * Iterator that returns each device attached to @shost.  This loop
   * takes a reference on each device and releases it at the end.  If
   * you break out of the loop, you must call scsi_device_put(sdev).
   */
  #define shost_for_each_device(sdev, shost) \
  	for ((sdev) = __scsi_iterate_devices((shost), NULL); \
  	     (sdev); \
  	     (sdev) = __scsi_iterate_devices((shost), (sdev)))
  
  /**
   * __shost_for_each_device - iterate over all devices of a host (UNLOCKED)
   * @sdev: the &struct scsi_device to use as a cursor
   * @shost: the &struct scsi_host to iterate over
   *
   * Iterator that returns each device attached to @shost.  It does _not_
   * take a reference on the scsi_device, so the whole loop must be
   * protected by shost->host_lock.
   *
   * Note: The only reason to use this is because you need to access the
   * device list in interrupt context.  Otherwise you really want to use
   * shost_for_each_device instead.
   */
  #define __shost_for_each_device(sdev, shost) \
  	list_for_each_entry((sdev), &((shost)->__devices), siblings)
  
  extern void scsi_adjust_queue_depth(struct scsi_device *, int, int);
  extern int scsi_track_queue_full(struct scsi_device *, int);
  
  extern int scsi_set_medium_removal(struct scsi_device *, char);
  
  extern int scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
  			   unsigned char *buffer, int len, int timeout,
  			   int retries, struct scsi_mode_data *data,
  			   struct scsi_sense_hdr *);
  extern int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
  			    int modepage, unsigned char *buffer, int len,
  			    int timeout, int retries,
  			    struct scsi_mode_data *data,
  			    struct scsi_sense_hdr *);
  extern int scsi_test_unit_ready(struct scsi_device *sdev, int timeout,
  				int retries);
  extern int scsi_device_set_state(struct scsi_device *sdev,
  				 enum scsi_device_state state);
  extern int scsi_device_quiesce(struct scsi_device *sdev);
  extern void scsi_device_resume(struct scsi_device *sdev);
  extern void scsi_target_quiesce(struct scsi_target *);
  extern void scsi_target_resume(struct scsi_target *);
  extern void scsi_scan_target(struct device *parent, unsigned int channel,
  			     unsigned int id, unsigned int lun, int rescan);
  extern void scsi_target_reap(struct scsi_target *);
  extern void scsi_target_block(struct device *);
  extern void scsi_target_unblock(struct device *);
  extern void scsi_remove_target(struct device *);
  extern void int_to_scsilun(unsigned int, struct scsi_lun *);
  extern const char *scsi_device_state_name(enum scsi_device_state);
  extern int scsi_is_sdev_device(const struct device *);
  extern int scsi_is_target_device(const struct device *);
  extern int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
  			int data_direction, void *buffer, unsigned bufflen,
  			unsigned char *sense, int timeout, int retries,
  			int flag);
  extern int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
  			    int data_direction, void *buffer, unsigned bufflen,
  			    struct scsi_sense_hdr *, int timeout, int retries);
  extern int scsi_execute_async(struct scsi_device *sdev,
  			      const unsigned char *cmd, int cmd_len, int data_direction,
  			      void *buffer, unsigned bufflen, int use_sg,
  			      int timeout, int retries, void *privdata,
  			      void (*done)(void *, char *, int, int),
  			      gfp_t gfp);
  
  static inline int __must_check scsi_device_reprobe(struct scsi_device *sdev)
  {
  	return device_reprobe(&sdev->sdev_gendev);
  }
  
  static inline unsigned int sdev_channel(struct scsi_device *sdev)
  {
  	return sdev->channel;
  }
  
  static inline unsigned int sdev_id(struct scsi_device *sdev)
  {
  	return sdev->id;
  }
  
  #define scmd_id(scmd) sdev_id((scmd)->device)
  #define scmd_channel(scmd) sdev_channel((scmd)->device)
  
  static inline int scsi_device_online(struct scsi_device *sdev)
  {
  	return sdev->sdev_state != SDEV_OFFLINE;
  }
  
  /* accessor functions for the SCSI parameters */
  static inline int scsi_device_sync(struct scsi_device *sdev)
  {
  	return sdev->sdtr;
  }
  static inline int scsi_device_wide(struct scsi_device *sdev)
  {
  	return sdev->wdtr;
  }
  static inline int scsi_device_dt(struct scsi_device *sdev)
  {
  	return sdev->ppr;
  }
  static inline int scsi_device_dt_only(struct scsi_device *sdev)
  {
  	if (sdev->inquiry_len < 57)
  		return 0;
  	return (sdev->inquiry[56] & 0x0c) == 0x04;
  }
  static inline int scsi_device_ius(struct scsi_device *sdev)
  {
  	if (sdev->inquiry_len < 57)
  		return 0;
  	return sdev->inquiry[56] & 0x01;
  }
  static inline int scsi_device_qas(struct scsi_device *sdev)
  {
  	if (sdev->inquiry_len < 57)
  		return 0;
  	return sdev->inquiry[56] & 0x02;
  }
  
  #define MODULE_ALIAS_SCSI_DEVICE(type) \
  	MODULE_ALIAS("scsi:t-" __stringify(type) "*")
  #define SCSI_DEVICE_MODALIAS_FMT "scsi:t-0x%02x"
  
  #endif /* _SCSI_SCSI_DEVICE_H */
  