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 | |