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 | |
26 | struct 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) \ |
44 | static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \ |
45 | module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \ |
46 | MODULE_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 | */ |
52 | struct dm_kcopyd_client; |
53 | struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle); |
54 | void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc); |
55 | void 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 | */ |
64 | typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned int long write_err, |
65 | void *context); |
66 | |
67 | void 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 | */ |
82 | void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc, |
83 | dm_kcopyd_notify_fn fn, void *context); |
84 | void dm_kcopyd_do_callback(void *job, int read_err, unsigned int long write_err); |
85 | |
86 | void 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 | |