1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (C) 2003 Sistina Software
4 * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.
5 *
6 * Device-Mapper low-level I/O.
7 *
8 * This file is released under the GPL.
9 */
10
11 #ifndef _LINUX_DM_IO_H
12 #define _LINUX_DM_IO_H
13
14 #ifdef __KERNEL__
15
16 #include <linux/types.h>
17 #include <linux/blk_types.h>
18
19 struct dm_io_region {
20 struct block_device *bdev;
21 sector_t sector;
22 sector_t count; /* If this is zero the region is ignored. */
23 };
24
25 struct page_list {
26 struct page_list *next;
27 struct page *page;
28 };
29
30 typedef void (*io_notify_fn)(unsigned int long error, void *context);
31
32 enum dm_io_mem_type {
33 DM_IO_PAGE_LIST,/* Page list */
34 DM_IO_BIO, /* Bio vector */
35 DM_IO_VMA, /* Virtual memory area */
36 DM_IO_KMEM, /* Kernel memory */
37 };
38
39 struct dm_io_memory {
40 enum dm_io_mem_type type;
41
42 unsigned int offset;
43
44 union {
45 struct page_list *pl;
46 struct bio *bio;
47 void *vma;
48 void *addr;
49 } ptr;
50 };
51
52 struct dm_io_notify {
53 io_notify_fn fn; /* Callback for asynchronous requests */
54 void *context; /* Passed to callback */
55 };
56
57 /*
58 * IO request structure
59 */
60 struct dm_io_client;
61 struct dm_io_request {
62 blk_opf_t bi_opf; /* Request type and flags */
63 struct dm_io_memory mem; /* Memory to use for io */
64 struct dm_io_notify notify; /* Synchronous if notify.fn is NULL */
65 struct dm_io_client *client; /* Client memory handler */
66 };
67
68 /*
69 * For async io calls, users can alternatively use the dm_io() function below
70 * and dm_io_client_create() to create private mempools for the client.
71 *
72 * Create/destroy may block.
73 */
74 struct dm_io_client *dm_io_client_create(void);
75 void dm_io_client_destroy(struct dm_io_client *client);
76
77 /*
78 * IO interface using private per-client pools.
79 * Each bit in the optional 'sync_error_bits' bitset indicates whether an
80 * error occurred doing io to the corresponding region.
81 */
82 int dm_io(struct dm_io_request *io_req, unsigned int num_regions,
83 struct dm_io_region *region, unsigned int long *sync_error_bits,
84 unsigned short ioprio);
85
86 #endif /* __KERNEL__ */
87 #endif /* _LINUX_DM_IO_H */
88
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