linux/include/linux/dm-kcopyd.h
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   1/*
   2 * Copyright (C) 2001 - 2003 Sistina Software
   3 * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.
   4 *
   5 * kcopyd provides a simple interface for copying an area of one
   6 * block-device to one or more other block-devices, either synchronous
   7 * or with an asynchronous completion notification.
   8 *
   9 * This file is released under the GPL.
  10 */
  11
  12#ifndef _LINUX_DM_KCOPYD_H
  13#define _LINUX_DM_KCOPYD_H
  14
  15#ifdef __KERNEL__
  16
  17#include <linux/dm-io.h>
  18
  19/* FIXME: make this configurable */
  20#define DM_KCOPYD_MAX_REGIONS 8
  21
  22#define DM_KCOPYD_IGNORE_ERROR 1
  23
  24/*
  25 * To use kcopyd you must first create a dm_kcopyd_client object.
  26 */
  27struct dm_kcopyd_client;
  28struct dm_kcopyd_client *dm_kcopyd_client_create(void);
  29void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);
  30
  31/*
  32 * Submit a copy job to kcopyd.  This is built on top of the
  33 * previous three fns.
  34 *
  35 * read_err is a boolean,
  36 * write_err is a bitset, with 1 bit for each destination region
  37 */
  38typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned long write_err,
  39                                    void *context);
  40
  41int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
  42                   unsigned num_dests, struct dm_io_region *dests,
  43                   unsigned flags, dm_kcopyd_notify_fn fn, void *context);
  44
  45/*
  46 * Prepare a callback and submit it via the kcopyd thread.
  47 *
  48 * dm_kcopyd_prepare_callback allocates a callback structure and returns it.
  49 * It must not be called from interrupt context.
  50 * The returned value should be passed into dm_kcopyd_do_callback.
  51 *
  52 * dm_kcopyd_do_callback submits the callback.
  53 * It may be called from interrupt context.
  54 * The callback is issued from the kcopyd thread.
  55 */
  56void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
  57                                 dm_kcopyd_notify_fn fn, void *context);
  58void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err);
  59
  60int dm_kcopyd_zero(struct dm_kcopyd_client *kc,
  61                   unsigned num_dests, struct dm_io_region *dests,
  62                   unsigned flags, dm_kcopyd_notify_fn fn, void *context);
  63
  64#endif  /* __KERNEL__ */
  65#endif  /* _LINUX_DM_KCOPYD_H */
  66
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