dm-bitset.c revision 7a87edfee75151abb69d47dba2277ff2de0f6071 
1/*
2 * Copyright (C) 2012 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-bitset.h"
8#include "dm-transaction-manager.h"
9
10#include <linux/export.h>
11#include <linux/device-mapper.h>
12
13#define DM_MSG_PREFIX "bitset"
14#define BITS_PER_ARRAY_ENTRY 64
15
16/*----------------------------------------------------------------*/
17
18static struct dm_btree_value_type bitset_bvt = {
19	.context = NULL,
20	.size = sizeof(__le64),
21	.inc = NULL,
22	.dec = NULL,
23	.equal = NULL,
24};
25
26/*----------------------------------------------------------------*/
27
28void dm_disk_bitset_init(struct dm_transaction_manager *tm,
29			 struct dm_disk_bitset *info)
30{
31	dm_array_info_init(&info->array_info, tm, &bitset_bvt);
32	info->current_index_set = false;
33}
34EXPORT_SYMBOL_GPL(dm_disk_bitset_init);
35
36int dm_bitset_empty(struct dm_disk_bitset *info, dm_block_t *root)
37{
38	return dm_array_empty(&info->array_info, root);
39}
40EXPORT_SYMBOL_GPL(dm_bitset_empty);
41
42int dm_bitset_resize(struct dm_disk_bitset *info, dm_block_t root,
43		     uint32_t old_nr_entries, uint32_t new_nr_entries,
44		     bool default_value, dm_block_t *new_root)
45{
46	uint32_t old_blocks = dm_div_up(old_nr_entries, BITS_PER_ARRAY_ENTRY);
47	uint32_t new_blocks = dm_div_up(new_nr_entries, BITS_PER_ARRAY_ENTRY);
48	__le64 value = default_value ? cpu_to_le64(~0) : cpu_to_le64(0);
49
50	__dm_bless_for_disk(&value);
51	return dm_array_resize(&info->array_info, root, old_blocks, new_blocks,
52			       &value, new_root);
53}
54EXPORT_SYMBOL_GPL(dm_bitset_resize);
55
56int dm_bitset_del(struct dm_disk_bitset *info, dm_block_t root)
57{
58	return dm_array_del(&info->array_info, root);
59}
60EXPORT_SYMBOL_GPL(dm_bitset_del);
61
62int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,
63		    dm_block_t *new_root)
64{
65	int r;
66	__le64 value;
67
68	if (!info->current_index_set)
69		return 0;
70
71	value = cpu_to_le64(info->current_bits);
72
73	__dm_bless_for_disk(&value);
74	r = dm_array_set_value(&info->array_info, root, info->current_index,
75			       &value, new_root);
76	if (r)
77		return r;
78
79	info->current_index_set = false;
80	return 0;
81}
82EXPORT_SYMBOL_GPL(dm_bitset_flush);
83
84static int read_bits(struct dm_disk_bitset *info, dm_block_t root,
85		     uint32_t array_index)
86{
87	int r;
88	__le64 value;
89
90	r = dm_array_get_value(&info->array_info, root, array_index, &value);
91	if (r)
92		return r;
93
94	info->current_bits = le64_to_cpu(value);
95	info->current_index_set = true;
96	info->current_index = array_index;
97	return 0;
98}
99
100static int get_array_entry(struct dm_disk_bitset *info, dm_block_t root,
101			   uint32_t index, dm_block_t *new_root)
102{
103	int r;
104	unsigned array_index = index / BITS_PER_ARRAY_ENTRY;
105
106	if (info->current_index_set) {
107		if (info->current_index == array_index)
108			return 0;
109
110		r = dm_bitset_flush(info, root, new_root);
111		if (r)
112			return r;
113	}
114
115	return read_bits(info, root, array_index);
116}
117
118int dm_bitset_set_bit(struct dm_disk_bitset *info, dm_block_t root,
119		      uint32_t index, dm_block_t *new_root)
120{
121	int r;
122	unsigned b = index % BITS_PER_ARRAY_ENTRY;
123
124	r = get_array_entry(info, root, index, new_root);
125	if (r)
126		return r;
127
128	set_bit(b, (unsigned long *) &info->current_bits);
129	return 0;
130}
131EXPORT_SYMBOL_GPL(dm_bitset_set_bit);
132
133int dm_bitset_clear_bit(struct dm_disk_bitset *info, dm_block_t root,
134			uint32_t index, dm_block_t *new_root)
135{
136	int r;
137	unsigned b = index % BITS_PER_ARRAY_ENTRY;
138
139	r = get_array_entry(info, root, index, new_root);
140	if (r)
141		return r;
142
143	clear_bit(b, (unsigned long *) &info->current_bits);
144	return 0;
145}
146EXPORT_SYMBOL_GPL(dm_bitset_clear_bit);
147
148int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root,
149		       uint32_t index, dm_block_t *new_root, bool *result)
150{
151	int r;
152	unsigned b = index % BITS_PER_ARRAY_ENTRY;
153
154	r = get_array_entry(info, root, index, new_root);
155	if (r)
156		return r;
157
158	*result = test_bit(b, (unsigned long *) &info->current_bits);
159	return 0;
160}
161EXPORT_SYMBOL_GPL(dm_bitset_test_bit);
162
163/*----------------------------------------------------------------*/
164