include/linux/dm-kcopyd.h

   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  */
  27 struct dm_kcopyd_client;
  28 struct dm_kcopyd_client *dm_kcopyd_client_create(void);
  29 void 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  */
  38 typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned long write_err,
  39                                     void *context);
  40
  41 int 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  */
  56 void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
  57                                  dm_kcopyd_notify_fn fn, void *context);
  58 void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err);
  59
  60 int 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 */