1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2001 - 2003 Sistina Software
4 * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.
5 *
6 * kcopyd provides a simple interface for copying an area of one
7 * block-device to one or more other block-devices, either synchronous
8 * or with an asynchronous completion notification.
9 *
10 * This file is released under the GPL.
11 */
12
13#ifndef _LINUX_DM_KCOPYD_H
14#define _LINUX_DM_KCOPYD_H
15
16#ifdef __KERNEL__
17
18#include <linux/dm-io.h>
19
20/* FIXME: make this configurable */
21#define DM_KCOPYD_MAX_REGIONS 8
22
23#define DM_KCOPYD_IGNORE_ERROR 1
24#define DM_KCOPYD_WRITE_SEQ 2
25
26struct dm_kcopyd_throttle {
27 unsigned int throttle;
28 unsigned int num_io_jobs;
29 unsigned int io_period;
30 unsigned int total_period;
31 unsigned int last_jiffies;
32};
33
34/*
35 * kcopyd clients that want to support throttling must pass an initialised
36 * dm_kcopyd_throttle struct into dm_kcopyd_client_create().
37 * Two or more clients may share the same instance of this struct between
38 * them if they wish to be throttled as a group.
39 *
40 * This macro also creates a corresponding module parameter to configure
41 * the amount of throttling.
42 */
43#define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) \
44static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \
45module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \
46MODULE_PARM_DESC(name, description)
47
48/*
49 * To use kcopyd you must first create a dm_kcopyd_client object.
50 * throttle can be NULL if you don't want any throttling.
51 */
52struct dm_kcopyd_client;
53struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle);
54void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);
55void dm_kcopyd_client_flush(struct dm_kcopyd_client *kc);
56
57/*
58 * Submit a copy job to kcopyd. This is built on top of the
59 * previous three fns.
60 *
61 * read_err is a boolean,
62 * write_err is a bitset, with 1 bit for each destination region
63 */
64typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned int long write_err,
65 void *context);
66
67void dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
68 unsigned int num_dests, struct dm_io_region *dests,
69 unsigned int flags, dm_kcopyd_notify_fn fn, void *context);
70
71/*
72 * Prepare a callback and submit it via the kcopyd thread.
73 *
74 * dm_kcopyd_prepare_callback allocates a callback structure and returns it.
75 * It must not be called from interrupt context.
76 * The returned value should be passed into dm_kcopyd_do_callback.
77 *
78 * dm_kcopyd_do_callback submits the callback.
79 * It may be called from interrupt context.
80 * The callback is issued from the kcopyd thread.
81 */
82void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
83 dm_kcopyd_notify_fn fn, void *context);
84void dm_kcopyd_do_callback(void *job, int read_err, unsigned int long write_err);
85
86void dm_kcopyd_zero(struct dm_kcopyd_client *kc,
87 unsigned int num_dests, struct dm_io_region *dests,
88 unsigned int flags, dm_kcopyd_notify_fn fn, void *context);
89
90#endif /* __KERNEL__ */
91#endif /* _LINUX_DM_KCOPYD_H */
92