/*

   * Copyright (C) 2001 - 2003 Sistina Software
   * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.

   *

   * kcopyd provides a simple interface for copying an area of one
   * block-device to one or more other block-devices, either synchronous
   * or with an asynchronous completion notification.

   *

   * This file is released under the GPL.

   */

  #ifndef _LINUX_DM_KCOPYD_H
  #define _LINUX_DM_KCOPYD_H
  
  #ifdef __KERNEL__

  #include <linux/dm-io.h>

  
  /* FIXME: make this configurable */

  #define DM_KCOPYD_MAX_REGIONS 8

  #define DM_KCOPYD_IGNORE_ERROR 1

  
  /*

   * To use kcopyd you must first create a dm_kcopyd_client object.

   */

  struct dm_kcopyd_client;

  struct dm_kcopyd_client *dm_kcopyd_client_create(void);

  void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);

  
  /*
   * Submit a copy job to kcopyd.  This is built on top of the
   * previous three fns.
   *
   * read_err is a boolean,
   * write_err is a bitset, with 1 bit for each destination region
   */

  typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned long write_err,
  				    void *context);

  int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
  		   unsigned num_dests, struct dm_io_region *dests,
  		   unsigned flags, dm_kcopyd_notify_fn fn, void *context);

  /*
   * Prepare a callback and submit it via the kcopyd thread.
   *
   * dm_kcopyd_prepare_callback allocates a callback structure and returns it.
   * It must not be called from interrupt context.
   * The returned value should be passed into dm_kcopyd_do_callback.
   *
   * dm_kcopyd_do_callback submits the callback.
   * It may be called from interrupt context.
   * The callback is issued from the kcopyd thread.
   */
  void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
  				 dm_kcopyd_notify_fn fn, void *context);
  void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err);

  int dm_kcopyd_zero(struct dm_kcopyd_client *kc,
  		   unsigned num_dests, struct dm_io_region *dests,
  		   unsigned flags, dm_kcopyd_notify_fn fn, void *context);

  #endif	/* __KERNEL__ */
  #endif	/* _LINUX_DM_KCOPYD_H */