/*
   * Copyright (C) 2001 Sistina Software (UK) Limited.

   * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.

   *
   * This file is released under the LGPL.
   */
  
  #ifndef _LINUX_DEVICE_MAPPER_H
  #define _LINUX_DEVICE_MAPPER_H

  #include <linux/bio.h>

  #include <linux/blkdev.h>

  struct dm_dev;

  struct dm_target;
  struct dm_table;

  struct mapped_device;

  struct bio_vec;

  
  typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
  
  union map_info {
  	void *ptr;
  	unsigned long long ll;

  	unsigned target_request_nr;

  };
  
  /*
   * In the constructor the target parameter will already have the
   * table, type, begin and len fields filled in.
   */
  typedef int (*dm_ctr_fn) (struct dm_target *target,
  			  unsigned int argc, char **argv);
  
  /*
   * The destructor doesn't need to free the dm_target, just
   * anything hidden ti->private.
   */
  typedef void (*dm_dtr_fn) (struct dm_target *ti);
  
  /*
   * The map function must return:
   * < 0: error
   * = 0: The target will handle the io by resubmitting it later

   * = 1: simple remap complete

   * = 2: The target wants to push back the io

   */
  typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
  			  union map_info *map_context);

  typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
  				  union map_info *map_context);

  
  /*
   * Returns:
   * < 0 : error (currently ignored)
   * 0   : ended successfully
   * 1   : for some reason the io has still not completed (eg,
   *       multipath target might want to requeue a failed io).

   * 2   : The target wants to push back the io

   */
  typedef int (*dm_endio_fn) (struct dm_target *ti,
  			    struct bio *bio, int error,
  			    union map_info *map_context);

  typedef int (*dm_request_endio_fn) (struct dm_target *ti,
  				    struct request *clone, int error,
  				    union map_info *map_context);

  typedef void (*dm_flush_fn) (struct dm_target *ti);

  typedef void (*dm_presuspend_fn) (struct dm_target *ti);
  typedef void (*dm_postsuspend_fn) (struct dm_target *ti);

  typedef int (*dm_preresume_fn) (struct dm_target *ti);

  typedef void (*dm_resume_fn) (struct dm_target *ti);
  
  typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
  			     char *result, unsigned int maxlen);
  
  typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);

  typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,

  			    unsigned long arg);

  typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
  			    struct bio_vec *biovec, int max_size);

  typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
  					   struct dm_dev *dev,

  					   sector_t start, sector_t len,

  					   void *data);
  
  typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
  				      iterate_devices_callout_fn fn,
  				      void *data);

  typedef void (*dm_io_hints_fn) (struct dm_target *ti,
  				struct queue_limits *limits);

  /*
   * Returns:
   *    0: The target can handle the next I/O immediately.
   *    1: The target can't handle the next I/O immediately.
   */
  typedef int (*dm_busy_fn) (struct dm_target *ti);

  void dm_error(const char *message);
  
  /*

   * Combine device limits.
   */

  int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,

  			 sector_t start, sector_t len, void *data);

  struct dm_dev {
  	struct block_device *bdev;

  	fmode_t mode;

  	char name[16];
  };

  /*

   * Constructors should call these functions to ensure destination devices
   * are opened/closed correctly.

   */

  int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
  						 struct dm_dev **result);

  void dm_put_device(struct dm_target *ti, struct dm_dev *d);
  
  /*
   * Information about a target type
   */

  
  /*
   * Target features
   */

  struct target_type {

  	uint64_t features;

  	const char *name;
  	struct module *module;

  	unsigned version[3];

  	dm_ctr_fn ctr;
  	dm_dtr_fn dtr;
  	dm_map_fn map;

  	dm_map_request_fn map_rq;

  	dm_endio_fn end_io;

  	dm_request_endio_fn rq_end_io;

  	dm_flush_fn flush;

  	dm_presuspend_fn presuspend;
  	dm_postsuspend_fn postsuspend;

  	dm_preresume_fn preresume;

  	dm_resume_fn resume;
  	dm_status_fn status;
  	dm_message_fn message;

  	dm_ioctl_fn ioctl;

  	dm_merge_fn merge;

  	dm_busy_fn busy;

  	dm_iterate_devices_fn iterate_devices;

  	dm_io_hints_fn io_hints;

  
  	/* For internal device-mapper use. */
  	struct list_head list;

  };

  struct dm_target {
  	struct dm_table *table;
  	struct target_type *type;
  
  	/* target limits */
  	sector_t begin;
  	sector_t len;

  	/* Always a power of 2 */
  	sector_t split_io;
  
  	/*

  	 * A number of zero-length barrier requests that will be submitted
  	 * to the target for the purpose of flushing cache.
  	 *

  	 * The request number will be placed in union map_info->target_request_nr.

  	 * It is a responsibility of the target driver to remap these requests
  	 * to the real underlying devices.
  	 */
  	unsigned num_flush_requests;

  	/*
  	 * The number of discard requests that will be submitted to the
  	 * target.  map_info->request_nr is used just like num_flush_requests.
  	 */
  	unsigned num_discard_requests;

  	/* target specific data */
  	void *private;
  
  	/* Used to provide an error string from the ctr */
  	char *error;
  };

  /* Each target can link one of these into the table */
  struct dm_target_callbacks {
  	struct list_head list;
  	int (*congested_fn) (struct dm_target_callbacks *, int);

  	void (*unplug_fn)(struct dm_target_callbacks *);

  };

  int dm_register_target(struct target_type *t);

  void dm_unregister_target(struct target_type *t);

  
  /*-----------------------------------------------------------------
   * Functions for creating and manipulating mapped devices.
   * Drop the reference with dm_put when you finish with the object.
   *---------------------------------------------------------------*/
  
  /*
   * DM_ANY_MINOR chooses the next available minor number.
   */
  #define DM_ANY_MINOR (-1)
  int dm_create(int minor, struct mapped_device **md);
  
  /*
   * Reference counting for md.
   */
  struct mapped_device *dm_get_md(dev_t dev);
  void dm_get(struct mapped_device *md);
  void dm_put(struct mapped_device *md);
  
  /*
   * An arbitrary pointer may be stored alongside a mapped device.
   */
  void dm_set_mdptr(struct mapped_device *md, void *ptr);
  void *dm_get_mdptr(struct mapped_device *md);
  
  /*
   * A device can still be used while suspended, but I/O is deferred.
   */

  int dm_suspend(struct mapped_device *md, unsigned suspend_flags);

  int dm_resume(struct mapped_device *md);
  
  /*
   * Event functions.
   */
  uint32_t dm_get_event_nr(struct mapped_device *md);
  int dm_wait_event(struct mapped_device *md, int event_nr);

  uint32_t dm_next_uevent_seq(struct mapped_device *md);
  void dm_uevent_add(struct mapped_device *md, struct list_head *elist);

  
  /*
   * Info functions.
   */

  const char *dm_device_name(struct mapped_device *md);

  int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);

  struct gendisk *dm_disk(struct mapped_device *md);

  int dm_suspended(struct dm_target *ti);

  int dm_noflush_suspending(struct dm_target *ti);

  union map_info *dm_get_mapinfo(struct bio *bio);

  union map_info *dm_get_rq_mapinfo(struct request *rq);

  
  /*
   * Geometry functions.
   */
  int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
  int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
  
  
  /*-----------------------------------------------------------------
   * Functions for manipulating device-mapper tables.
   *---------------------------------------------------------------*/
  
  /*
   * First create an empty table.
   */

  int dm_table_create(struct dm_table **result, fmode_t mode,

  		    unsigned num_targets, struct mapped_device *md);
  
  /*
   * Then call this once for each target.
   */
  int dm_table_add_target(struct dm_table *t, const char *type,
  			sector_t start, sector_t len, char *params);
  
  /*

   * Target_ctr should call this if it needs to add any callbacks.
   */
  void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
  
  /*

   * Finally call this to make the table ready for use.
   */
  int dm_table_complete(struct dm_table *t);
  
  /*

   * Unplug all devices in a table.
   */
  void dm_table_unplug_all(struct dm_table *t);
  
  /*

   * Table reference counting.
   */

  struct dm_table *dm_get_live_table(struct mapped_device *md);

  void dm_table_get(struct dm_table *t);
  void dm_table_put(struct dm_table *t);
  
  /*
   * Queries
   */
  sector_t dm_table_get_size(struct dm_table *t);
  unsigned int dm_table_get_num_targets(struct dm_table *t);

  fmode_t dm_table_get_mode(struct dm_table *t);

  struct mapped_device *dm_table_get_md(struct dm_table *t);
  
  /*
   * Trigger an event.
   */
  void dm_table_event(struct dm_table *t);
  
  /*
   * The device must be suspended before calling this method.

   * Returns the previous table, which the caller must destroy.

   */

  struct dm_table *dm_swap_table(struct mapped_device *md,
  			       struct dm_table *t);

  /*
   * A wrapper around vmalloc.
   */
  void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);

  /*-----------------------------------------------------------------
   * Macros.
   *---------------------------------------------------------------*/
  #define DM_NAME "device-mapper"

  #define DMCRIT(f, arg...) \
  	printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "
  ", ## arg)

  #define DMERR(f, arg...) \
  	printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "
  ", ## arg)
  #define DMERR_LIMIT(f, arg...) \
  	do { \
  		if (printk_ratelimit())	\
  			printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
  			       f "
  ", ## arg); \
  	} while (0)
  
  #define DMWARN(f, arg...) \
  	printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "
  ", ## arg)
  #define DMWARN_LIMIT(f, arg...) \
  	do { \
  		if (printk_ratelimit())	\
  			printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
  			       f "
  ", ## arg); \
  	} while (0)
  
  #define DMINFO(f, arg...) \
  	printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "
  ", ## arg)
  #define DMINFO_LIMIT(f, arg...) \
  	do { \
  		if (printk_ratelimit())	\
  			printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
  			       "
  ", ## arg); \
  	} while (0)
  
  #ifdef CONFIG_DM_DEBUG
  #  define DMDEBUG(f, arg...) \
  	printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "
  ", ## arg)
  #  define DMDEBUG_LIMIT(f, arg...) \
  	do { \
  		if (printk_ratelimit())	\
  			printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
  			       "
  ", ## arg); \
  	} while (0)
  #else
  #  define DMDEBUG(f, arg...) do {} while (0)
  #  define DMDEBUG_LIMIT(f, arg...) do {} while (0)
  #endif
  
  #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
  			  0 : scnprintf(result + sz, maxlen - sz, x))
  
  #define SECTOR_SHIFT 9
  
  /*
   * Definitions of return values from target end_io function.
   */
  #define DM_ENDIO_INCOMPLETE	1
  #define DM_ENDIO_REQUEUE	2
  
  /*
   * Definitions of return values from target map function.
   */
  #define DM_MAPIO_SUBMITTED	0
  #define DM_MAPIO_REMAPPED	1
  #define DM_MAPIO_REQUEUE	DM_ENDIO_REQUEUE
  
  /*
   * Ceiling(n / sz)
   */
  #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
  
  #define dm_sector_div_up(n, sz) ( \
  { \
  	sector_t _r = ((n) + (sz) - 1); \
  	sector_div(_r, (sz)); \
  	_r; \
  } \
  )
  
  /*
   * ceiling(n / size) * size
   */
  #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))

  #define dm_array_too_big(fixed, obj, num) \
  	((num) > (UINT_MAX - (fixed)) / (obj))

  /*
   * Sector offset taken relative to the start of the target instead of
   * relative to the start of the device.
   */
  #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)

  static inline sector_t to_sector(unsigned long n)
  {
  	return (n >> SECTOR_SHIFT);
  }
  
  static inline unsigned long to_bytes(sector_t n)
  {
  	return (n << SECTOR_SHIFT);
  }

  /*-----------------------------------------------------------------
   * Helper for block layer and dm core operations
   *---------------------------------------------------------------*/
  void dm_dispatch_request(struct request *rq);
  void dm_requeue_unmapped_request(struct request *rq);
  void dm_kill_unmapped_request(struct request *rq, int error);
  int dm_underlying_device_busy(struct request_queue *q);

  #endif	/* _LINUX_DEVICE_MAPPER_H */