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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
24struct dm_kcopyd_throttle {
25 unsigned throttle;
26 unsigned num_io_jobs;
27 unsigned io_period;
28 unsigned total_period;
29 unsigned last_jiffies;
30};
31
32/*
33 * kcopyd clients that want to support throttling must pass an initialised
34 * dm_kcopyd_throttle struct into dm_kcopyd_client_create().
35 * Two or more clients may share the same instance of this struct between
36 * them if they wish to be throttled as a group.
37 *
38 * This macro also creates a corresponding module parameter to configure
39 * the amount of throttling.
40 */
41#define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) \
42static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \
43module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \
44MODULE_PARM_DESC(name, description)
45
46/*
47 * To use kcopyd you must first create a dm_kcopyd_client object.
48 * throttle can be NULL if you don't want any throttling.
49 */
50struct dm_kcopyd_client;
51struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle);
52void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);
53
54/*
55 * Submit a copy job to kcopyd. This is built on top of the
56 * previous three fns.
57 *
58 * read_err is a boolean,
59 * write_err is a bitset, with 1 bit for each destination region
60 */
61typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned long write_err,
62 void *context);
63
64int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
65 unsigned num_dests, struct dm_io_region *dests,
66 unsigned flags, dm_kcopyd_notify_fn fn, void *context);
67
68/*
69 * Prepare a callback and submit it via the kcopyd thread.
70 *
71 * dm_kcopyd_prepare_callback allocates a callback structure and returns it.
72 * It must not be called from interrupt context.
73 * The returned value should be passed into dm_kcopyd_do_callback.
74 *
75 * dm_kcopyd_do_callback submits the callback.
76 * It may be called from interrupt context.
77 * The callback is issued from the kcopyd thread.
78 */
79void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
80 dm_kcopyd_notify_fn fn, void *context);
81void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err);
82
83int dm_kcopyd_zero(struct dm_kcopyd_client *kc,
84 unsigned num_dests, struct dm_io_region *dests,
85 unsigned flags, dm_kcopyd_notify_fn fn, void *context);
86
87#endif /* __KERNEL__ */
88#endif /* _LINUX_DM_KCOPYD_H */