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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * Copyright (C) 2003 Sistina Software
3 *
4 * This file is released under the GPL.
5 */
6
7#ifndef _DM_IO_H
8#define _DM_IO_H
9
10#include "dm.h"
11
12/* FIXME make this configurable */
13#define DM_MAX_IO_REGIONS 8
14
15struct io_region {
16 struct block_device *bdev;
17 sector_t sector;
18 sector_t count;
19};
20
21struct page_list {
22 struct page_list *next;
23 struct page *page;
24};
25
26
27/*
28 * 'error' is a bitset, with each bit indicating whether an error
29 * occurred doing io to the corresponding region.
30 */
31typedef void (*io_notify_fn)(unsigned long error, void *context);
32
33
34/*
35 * Before anyone uses the IO interface they should call
36 * dm_io_get(), specifying roughly how many pages they are
37 * expecting to perform io on concurrently.
38 *
39 * This function may block.
40 */
41int dm_io_get(unsigned int num_pages);
42void dm_io_put(unsigned int num_pages);
43
44/*
45 * Synchronous IO.
46 *
47 * Please ensure that the rw flag in the next two functions is
48 * either READ or WRITE, ie. we don't take READA. Any
49 * regions with a zero count field will be ignored.
50 */
51int dm_io_sync(unsigned int num_regions, struct io_region *where, int rw,
52 struct page_list *pl, unsigned int offset,
53 unsigned long *error_bits);
54
55int dm_io_sync_bvec(unsigned int num_regions, struct io_region *where, int rw,
56 struct bio_vec *bvec, unsigned long *error_bits);
57
58int dm_io_sync_vm(unsigned int num_regions, struct io_region *where, int rw,
59 void *data, unsigned long *error_bits);
60
61/*
62 * Aynchronous IO.
63 *
64 * The 'where' array may be safely allocated on the stack since
65 * the function takes a copy.
66 */
67int dm_io_async(unsigned int num_regions, struct io_region *where, int rw,
68 struct page_list *pl, unsigned int offset,
69 io_notify_fn fn, void *context);
70
71int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw,
72 struct bio_vec *bvec, io_notify_fn fn, void *context);
73
74int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
75 void *data, io_notify_fn fn, void *context);
76
77#endif