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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 | #define DM_KCOPYD_WRITE_SEQ 2 | |
24 | ||
25 | struct dm_kcopyd_throttle { | |
26 | unsigned throttle; | |
27 | unsigned num_io_jobs; | |
28 | unsigned io_period; | |
29 | unsigned total_period; | |
30 | unsigned last_jiffies; | |
31 | }; | |
32 | ||
33 | /* | |
34 | * kcopyd clients that want to support throttling must pass an initialised | |
35 | * dm_kcopyd_throttle struct into dm_kcopyd_client_create(). | |
36 | * Two or more clients may share the same instance of this struct between | |
37 | * them if they wish to be throttled as a group. | |
38 | * | |
39 | * This macro also creates a corresponding module parameter to configure | |
40 | * the amount of throttling. | |
41 | */ | |
42 | #define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) \ | |
43 | static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \ | |
44 | module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \ | |
45 | MODULE_PARM_DESC(name, description) | |
46 | ||
47 | /* | |
48 | * To use kcopyd you must first create a dm_kcopyd_client object. | |
49 | * throttle can be NULL if you don't want any throttling. | |
50 | */ | |
51 | struct dm_kcopyd_client; | |
52 | struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle); | |
53 | void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc); | |
54 | ||
55 | /* | |
56 | * Submit a copy job to kcopyd. This is built on top of the | |
57 | * previous three fns. | |
58 | * | |
59 | * read_err is a boolean, | |
60 | * write_err is a bitset, with 1 bit for each destination region | |
61 | */ | |
62 | typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned long write_err, | |
63 | void *context); | |
64 | ||
65 | void dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, | |
66 | unsigned num_dests, struct dm_io_region *dests, | |
67 | unsigned flags, dm_kcopyd_notify_fn fn, void *context); | |
68 | ||
69 | /* | |
70 | * Prepare a callback and submit it via the kcopyd thread. | |
71 | * | |
72 | * dm_kcopyd_prepare_callback allocates a callback structure and returns it. | |
73 | * It must not be called from interrupt context. | |
74 | * The returned value should be passed into dm_kcopyd_do_callback. | |
75 | * | |
76 | * dm_kcopyd_do_callback submits the callback. | |
77 | * It may be called from interrupt context. | |
78 | * The callback is issued from the kcopyd thread. | |
79 | */ | |
80 | void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc, | |
81 | dm_kcopyd_notify_fn fn, void *context); | |
82 | void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err); | |
83 | ||
84 | void dm_kcopyd_zero(struct dm_kcopyd_client *kc, | |
85 | unsigned num_dests, struct dm_io_region *dests, | |
86 | unsigned flags, dm_kcopyd_notify_fn fn, void *context); | |
87 | ||
88 | #endif /* __KERNEL__ */ | |
89 | #endif /* _LINUX_DM_KCOPYD_H */ |