1 /* SPDX-License-Identifier: GPL-2.0-only */ <<
2 /* 1 /*
3 * Copyright (C) 2009-2011 Red Hat, Inc. 2 * Copyright (C) 2009-2011 Red Hat, Inc.
4 * 3 *
5 * Author: Mikulas Patocka <mpatocka@redhat.co 4 * Author: Mikulas Patocka <mpatocka@redhat.com>
6 * 5 *
7 * This file is released under the GPL. 6 * This file is released under the GPL.
8 */ 7 */
9 8
10 #ifndef _LINUX_DM_BUFIO_H 9 #ifndef _LINUX_DM_BUFIO_H
11 #define _LINUX_DM_BUFIO_H 10 #define _LINUX_DM_BUFIO_H
12 11
13 #include <linux/blkdev.h> 12 #include <linux/blkdev.h>
14 #include <linux/types.h> 13 #include <linux/types.h>
15 14
16 /*-------------------------------------------- 15 /*----------------------------------------------------------------*/
17 16
18 struct dm_bufio_client; 17 struct dm_bufio_client;
19 struct dm_buffer; 18 struct dm_buffer;
20 19
21 /* 20 /*
22 * Flags for dm_bufio_client_create 21 * Flags for dm_bufio_client_create
23 */ 22 */
24 #define DM_BUFIO_CLIENT_NO_SLEEP 0x1 23 #define DM_BUFIO_CLIENT_NO_SLEEP 0x1
25 24
26 /* 25 /*
27 * Create a buffered IO cache on a given devic 26 * Create a buffered IO cache on a given device
28 */ 27 */
29 struct dm_bufio_client * 28 struct dm_bufio_client *
30 dm_bufio_client_create(struct block_device *bd !! 29 dm_bufio_client_create(struct block_device *bdev, unsigned block_size,
31 unsigned int reserved_b !! 30 unsigned reserved_buffers, unsigned aux_size,
32 void (*alloc_callback)( 31 void (*alloc_callback)(struct dm_buffer *),
33 void (*write_callback)( 32 void (*write_callback)(struct dm_buffer *),
34 unsigned int flags); 33 unsigned int flags);
35 34
36 /* 35 /*
37 * Release a buffered IO cache. 36 * Release a buffered IO cache.
38 */ 37 */
39 void dm_bufio_client_destroy(struct dm_bufio_c 38 void dm_bufio_client_destroy(struct dm_bufio_client *c);
40 39
41 void dm_bufio_client_reset(struct dm_bufio_cli <<
42 <<
43 /* 40 /*
44 * Set the sector range. 41 * Set the sector range.
45 * When this function is called, there must be 42 * When this function is called, there must be no I/O in progress on the bufio
46 * client. 43 * client.
47 */ 44 */
48 void dm_bufio_set_sector_offset(struct dm_bufi 45 void dm_bufio_set_sector_offset(struct dm_bufio_client *c, sector_t start);
49 46
50 /* 47 /*
51 * WARNING: to avoid deadlocks, these conditio 48 * WARNING: to avoid deadlocks, these conditions are observed:
52 * 49 *
53 * - At most one thread can hold at most "rese 50 * - At most one thread can hold at most "reserved_buffers" simultaneously.
54 * - Each other threads can hold at most one b 51 * - Each other threads can hold at most one buffer.
55 * - Threads which call only dm_bufio_get can 52 * - Threads which call only dm_bufio_get can hold unlimited number of
56 * buffers. 53 * buffers.
57 */ 54 */
58 55
59 /* 56 /*
60 * Read a given block from disk. Returns point 57 * Read a given block from disk. Returns pointer to data. Returns a
61 * pointer to dm_buffer that can be used to re 58 * pointer to dm_buffer that can be used to release the buffer or to make
62 * it dirty. 59 * it dirty.
63 */ 60 */
64 void *dm_bufio_read(struct dm_bufio_client *c, 61 void *dm_bufio_read(struct dm_bufio_client *c, sector_t block,
65 struct dm_buffer **bp); 62 struct dm_buffer **bp);
66 63
67 void *dm_bufio_read_with_ioprio(struct dm_bufi <<
68 struct dm_buff <<
69 <<
70 /* 64 /*
71 * Like dm_bufio_read, but return buffer from 65 * Like dm_bufio_read, but return buffer from cache, don't read
72 * it. If the buffer is not in the cache, retu 66 * it. If the buffer is not in the cache, return NULL.
73 */ 67 */
74 void *dm_bufio_get(struct dm_bufio_client *c, 68 void *dm_bufio_get(struct dm_bufio_client *c, sector_t block,
75 struct dm_buffer **bp); 69 struct dm_buffer **bp);
76 70
77 /* 71 /*
78 * Like dm_bufio_read, but don't read anything 72 * Like dm_bufio_read, but don't read anything from the disk. It is
79 * expected that the caller initializes the bu 73 * expected that the caller initializes the buffer and marks it dirty.
80 */ 74 */
81 void *dm_bufio_new(struct dm_bufio_client *c, 75 void *dm_bufio_new(struct dm_bufio_client *c, sector_t block,
82 struct dm_buffer **bp); 76 struct dm_buffer **bp);
83 77
84 /* 78 /*
85 * Prefetch the specified blocks to the cache. 79 * Prefetch the specified blocks to the cache.
86 * The function starts to read the blocks and 80 * The function starts to read the blocks and returns without waiting for
87 * I/O to finish. 81 * I/O to finish.
88 */ 82 */
89 void dm_bufio_prefetch(struct dm_bufio_client 83 void dm_bufio_prefetch(struct dm_bufio_client *c,
90 sector_t block, unsigne !! 84 sector_t block, unsigned n_blocks);
91 <<
92 void dm_bufio_prefetch_with_ioprio(struct dm_b <<
93 sector_t block <<
94 unsigned short <<
95 85
96 /* 86 /*
97 * Release a reference obtained with dm_bufio_ 87 * Release a reference obtained with dm_bufio_{read,get,new}. The data
98 * pointer and dm_buffer pointer is no longer 88 * pointer and dm_buffer pointer is no longer valid after this call.
99 */ 89 */
100 void dm_bufio_release(struct dm_buffer *b); 90 void dm_bufio_release(struct dm_buffer *b);
101 91
102 /* 92 /*
103 * Mark a buffer dirty. It should be called af 93 * Mark a buffer dirty. It should be called after the buffer is modified.
104 * 94 *
105 * In case of memory pressure, the buffer may 95 * In case of memory pressure, the buffer may be written after
106 * dm_bufio_mark_buffer_dirty, but before dm_b 96 * dm_bufio_mark_buffer_dirty, but before dm_bufio_write_dirty_buffers. So
107 * dm_bufio_write_dirty_buffers guarantees tha 97 * dm_bufio_write_dirty_buffers guarantees that the buffer is on-disk but
108 * the actual writing may occur earlier. 98 * the actual writing may occur earlier.
109 */ 99 */
110 void dm_bufio_mark_buffer_dirty(struct dm_buff 100 void dm_bufio_mark_buffer_dirty(struct dm_buffer *b);
111 101
112 /* 102 /*
113 * Mark a part of the buffer dirty. 103 * Mark a part of the buffer dirty.
114 * 104 *
115 * The specified part of the buffer is schedul 105 * The specified part of the buffer is scheduled to be written. dm-bufio may
116 * write the specified part of the buffer or i 106 * write the specified part of the buffer or it may write a larger superset.
117 */ 107 */
118 void dm_bufio_mark_partial_buffer_dirty(struct 108 void dm_bufio_mark_partial_buffer_dirty(struct dm_buffer *b,
119 unsign !! 109 unsigned start, unsigned end);
120 110
121 /* 111 /*
122 * Initiate writing of dirty buffers, without 112 * Initiate writing of dirty buffers, without waiting for completion.
123 */ 113 */
124 void dm_bufio_write_dirty_buffers_async(struct 114 void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c);
125 115
126 /* 116 /*
127 * Write all dirty buffers. Guarantees that al 117 * Write all dirty buffers. Guarantees that all dirty buffers created prior
128 * to this call are on disk when this call exi 118 * to this call are on disk when this call exits.
129 */ 119 */
130 int dm_bufio_write_dirty_buffers(struct dm_buf 120 int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c);
131 121
132 /* 122 /*
133 * Send an empty write barrier to the device t 123 * Send an empty write barrier to the device to flush hardware disk cache.
134 */ 124 */
135 int dm_bufio_issue_flush(struct dm_bufio_clien 125 int dm_bufio_issue_flush(struct dm_bufio_client *c);
136 126
137 /* 127 /*
138 * Send a discard request to the underlying de 128 * Send a discard request to the underlying device.
139 */ 129 */
140 int dm_bufio_issue_discard(struct dm_bufio_cli 130 int dm_bufio_issue_discard(struct dm_bufio_client *c, sector_t block, sector_t count);
141 131
142 /* 132 /*
>> 133 * Like dm_bufio_release but also move the buffer to the new
>> 134 * block. dm_bufio_write_dirty_buffers is needed to commit the new block.
>> 135 */
>> 136 void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block);
>> 137
>> 138 /*
143 * Free the given buffer. 139 * Free the given buffer.
144 * This is just a hint, if the buffer is in us 140 * This is just a hint, if the buffer is in use or dirty, this function
145 * does nothing. 141 * does nothing.
146 */ 142 */
147 void dm_bufio_forget(struct dm_bufio_client *c 143 void dm_bufio_forget(struct dm_bufio_client *c, sector_t block);
148 144
149 /* 145 /*
150 * Free the given range of buffers. 146 * Free the given range of buffers.
151 * This is just a hint, if the buffer is in us 147 * This is just a hint, if the buffer is in use or dirty, this function
152 * does nothing. 148 * does nothing.
153 */ 149 */
154 void dm_bufio_forget_buffers(struct dm_bufio_c 150 void dm_bufio_forget_buffers(struct dm_bufio_client *c, sector_t block, sector_t n_blocks);
155 151
156 /* 152 /*
157 * Set the minimum number of buffers before cl 153 * Set the minimum number of buffers before cleanup happens.
158 */ 154 */
159 void dm_bufio_set_minimum_buffers(struct dm_bu !! 155 void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned n);
160 156
161 unsigned int dm_bufio_get_block_size(struct dm !! 157 unsigned dm_bufio_get_block_size(struct dm_bufio_client *c);
162 sector_t dm_bufio_get_device_size(struct dm_bu 158 sector_t dm_bufio_get_device_size(struct dm_bufio_client *c);
163 struct dm_io_client *dm_bufio_get_dm_io_client 159 struct dm_io_client *dm_bufio_get_dm_io_client(struct dm_bufio_client *c);
164 sector_t dm_bufio_get_block_number(struct dm_b 160 sector_t dm_bufio_get_block_number(struct dm_buffer *b);
165 void *dm_bufio_get_block_data(struct dm_buffer 161 void *dm_bufio_get_block_data(struct dm_buffer *b);
166 void *dm_bufio_get_aux_data(struct dm_buffer * 162 void *dm_bufio_get_aux_data(struct dm_buffer *b);
167 struct dm_bufio_client *dm_bufio_get_client(st 163 struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b);
168 164
169 /*-------------------------------------------- 165 /*----------------------------------------------------------------*/
170 166
171 #endif 167 #endif
172 168
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