Linux kernel mirror (for testing)
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1/*
2 * Copyright (C) 2003 Sistina Software
3 * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.
4 *
5 * Device-Mapper low-level I/O.
6 *
7 * This file is released under the GPL.
8 */
9
10#ifndef _LINUX_DM_IO_H
11#define _LINUX_DM_IO_H
12
13#ifdef __KERNEL__
14
15#include <linux/types.h>
16#include <linux/blk_types.h>
17
18struct dm_io_region {
19 struct block_device *bdev;
20 sector_t sector;
21 sector_t count; /* If this is zero the region is ignored. */
22};
23
24struct page_list {
25 struct page_list *next;
26 struct page *page;
27};
28
29typedef void (*io_notify_fn)(unsigned long error, void *context);
30
31enum dm_io_mem_type {
32 DM_IO_PAGE_LIST,/* Page list */
33 DM_IO_BIO, /* Bio vector */
34 DM_IO_VMA, /* Virtual memory area */
35 DM_IO_KMEM, /* Kernel memory */
36};
37
38struct dm_io_memory {
39 enum dm_io_mem_type type;
40
41 unsigned offset;
42
43 union {
44 struct page_list *pl;
45 struct bio *bio;
46 void *vma;
47 void *addr;
48 } ptr;
49};
50
51struct dm_io_notify {
52 io_notify_fn fn; /* Callback for asynchronous requests */
53 void *context; /* Passed to callback */
54};
55
56/*
57 * IO request structure
58 */
59struct dm_io_client;
60struct dm_io_request {
61 blk_opf_t bi_opf; /* Request type and flags */
62 struct dm_io_memory mem; /* Memory to use for io */
63 struct dm_io_notify notify; /* Synchronous if notify.fn is NULL */
64 struct dm_io_client *client; /* Client memory handler */
65};
66
67/*
68 * For async io calls, users can alternatively use the dm_io() function below
69 * and dm_io_client_create() to create private mempools for the client.
70 *
71 * Create/destroy may block.
72 */
73struct dm_io_client *dm_io_client_create(void);
74void dm_io_client_destroy(struct dm_io_client *client);
75
76/*
77 * IO interface using private per-client pools.
78 * Each bit in the optional 'sync_error_bits' bitset indicates whether an
79 * error occurred doing io to the corresponding region.
80 */
81int dm_io(struct dm_io_request *io_req, unsigned num_regions,
82 struct dm_io_region *region, unsigned long *sync_error_bits);
83
84#endif /* __KERNEL__ */
85#endif /* _LINUX_DM_IO_H */