1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Red Hat, Inc.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-bitset.h"
9#include "dm-transaction-manager.h"
10
11#include <linux/export.h>
12#include <linux/device-mapper.h>
13
14#define DM_MSG_PREFIX "bitset"
15#define BITS_PER_ARRAY_ENTRY 64
16
17/*----------------------------------------------------------------*/
18
19static struct dm_btree_value_type bitset_bvt = {
20	.context = NULL,
21	.size = sizeof(__le64),
22	.inc = NULL,
23	.dec = NULL,
24	.equal = NULL,
25};
26
27/*----------------------------------------------------------------*/
28
29void dm_disk_bitset_init(struct dm_transaction_manager *tm,
30			 struct dm_disk_bitset *info)
31{
32	dm_array_info_init(&info->array_info, tm, &bitset_bvt);
33	info->current_index_set = false;
34}
35EXPORT_SYMBOL_GPL(dm_disk_bitset_init);
36
37int dm_bitset_empty(struct dm_disk_bitset *info, dm_block_t *root)
38{
39	return dm_array_empty(&info->array_info, root);
40}
41EXPORT_SYMBOL_GPL(dm_bitset_empty);
42
43struct packer_context {
44	bit_value_fn fn;
45	unsigned int nr_bits;
46	void *context;
47};
48
49static int pack_bits(uint32_t index, void *value, void *context)
50{
51	int r;
52	struct packer_context *p = context;
53	unsigned int bit, nr = min(64u, p->nr_bits - (index * 64));
54	uint64_t word = 0;
55	bool bv;
56
57	for (bit = 0; bit < nr; bit++) {
58		r = p->fn(index * 64 + bit, &bv, p->context);
59		if (r)
60			return r;
61
62		if (bv)
63			set_bit(bit, (unsigned long *) &word);
64		else
65			clear_bit(bit, (unsigned long *) &word);
66	}
67
68	*((__le64 *) value) = cpu_to_le64(word);
69
70	return 0;
71}
72
73int dm_bitset_new(struct dm_disk_bitset *info, dm_block_t *root,
74		  uint32_t size, bit_value_fn fn, void *context)
75{
76	struct packer_context p;
77
78	p.fn = fn;
79	p.nr_bits = size;
80	p.context = context;
81
82	return dm_array_new(&info->array_info, root, dm_div_up(size, 64), pack_bits, &p);
83}
84EXPORT_SYMBOL_GPL(dm_bitset_new);
85
86int dm_bitset_resize(struct dm_disk_bitset *info, dm_block_t root,
87		     uint32_t old_nr_entries, uint32_t new_nr_entries,
88		     bool default_value, dm_block_t *new_root)
89{
90	uint32_t old_blocks = dm_div_up(old_nr_entries, BITS_PER_ARRAY_ENTRY);
91	uint32_t new_blocks = dm_div_up(new_nr_entries, BITS_PER_ARRAY_ENTRY);
92	__le64 value = default_value ? cpu_to_le64(~0) : cpu_to_le64(0);
93
94	__dm_bless_for_disk(&value);
95	return dm_array_resize(&info->array_info, root, old_blocks, new_blocks,
96			       &value, new_root);
97}
98EXPORT_SYMBOL_GPL(dm_bitset_resize);
99
100int dm_bitset_del(struct dm_disk_bitset *info, dm_block_t root)
101{
102	return dm_array_del(&info->array_info, root);
103}
104EXPORT_SYMBOL_GPL(dm_bitset_del);
105
106int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,
107		    dm_block_t *new_root)
108{
109	int r;
110	__le64 value;
111
112	if (!info->current_index_set || !info->dirty)
113		return 0;
114
115	value = cpu_to_le64(info->current_bits);
116
117	__dm_bless_for_disk(&value);
118	r = dm_array_set_value(&info->array_info, root, info->current_index,
119			       &value, new_root);
120	if (r)
121		return r;
122
123	info->current_index_set = false;
124	info->dirty = false;
125
126	return 0;
127}
128EXPORT_SYMBOL_GPL(dm_bitset_flush);
129
130static int read_bits(struct dm_disk_bitset *info, dm_block_t root,
131		     uint32_t array_index)
132{
133	int r;
134	__le64 value;
135
136	r = dm_array_get_value(&info->array_info, root, array_index, &value);
137	if (r)
138		return r;
139
140	info->current_bits = le64_to_cpu(value);
141	info->current_index_set = true;
142	info->current_index = array_index;
143	info->dirty = false;
144
145	return 0;
146}
147
148static int get_array_entry(struct dm_disk_bitset *info, dm_block_t root,
149			   uint32_t index, dm_block_t *new_root)
150{
151	int r;
152	unsigned int array_index = index / BITS_PER_ARRAY_ENTRY;
153
154	if (info->current_index_set) {
155		if (info->current_index == array_index)
156			return 0;
157
158		r = dm_bitset_flush(info, root, new_root);
159		if (r)
160			return r;
161	}
162
163	return read_bits(info, root, array_index);
164}
165
166int dm_bitset_set_bit(struct dm_disk_bitset *info, dm_block_t root,
167		      uint32_t index, dm_block_t *new_root)
168{
169	int r;
170	unsigned int b = index % BITS_PER_ARRAY_ENTRY;
171
172	r = get_array_entry(info, root, index, new_root);
173	if (r)
174		return r;
175
176	set_bit(b, (unsigned long *) &info->current_bits);
177	info->dirty = true;
178
179	return 0;
180}
181EXPORT_SYMBOL_GPL(dm_bitset_set_bit);
182
183int dm_bitset_clear_bit(struct dm_disk_bitset *info, dm_block_t root,
184			uint32_t index, dm_block_t *new_root)
185{
186	int r;
187	unsigned int b = index % BITS_PER_ARRAY_ENTRY;
188
189	r = get_array_entry(info, root, index, new_root);
190	if (r)
191		return r;
192
193	clear_bit(b, (unsigned long *) &info->current_bits);
194	info->dirty = true;
195
196	return 0;
197}
198EXPORT_SYMBOL_GPL(dm_bitset_clear_bit);
199
200int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root,
201		       uint32_t index, dm_block_t *new_root, bool *result)
202{
203	int r;
204	unsigned int b = index % BITS_PER_ARRAY_ENTRY;
205
206	r = get_array_entry(info, root, index, new_root);
207	if (r)
208		return r;
209
210	*result = test_bit(b, (unsigned long *) &info->current_bits);
211	return 0;
212}
213EXPORT_SYMBOL_GPL(dm_bitset_test_bit);
214
215static int cursor_next_array_entry(struct dm_bitset_cursor *c)
216{
217	int r;
218	__le64 *value;
219
220	r = dm_array_cursor_next(&c->cursor);
221	if (r)
222		return r;
223
224	dm_array_cursor_get_value(&c->cursor, (void **) &value);
225	c->array_index++;
226	c->bit_index = 0;
227	c->current_bits = le64_to_cpu(*value);
228	return 0;
229}
230
231int dm_bitset_cursor_begin(struct dm_disk_bitset *info,
232			   dm_block_t root, uint32_t nr_entries,
233			   struct dm_bitset_cursor *c)
234{
235	int r;
236	__le64 *value;
237
238	if (!nr_entries)
239		return -ENODATA;
240
241	c->info = info;
242	c->entries_remaining = nr_entries;
243
244	r = dm_array_cursor_begin(&info->array_info, root, &c->cursor);
245	if (r)
246		return r;
247
248	dm_array_cursor_get_value(&c->cursor, (void **) &value);
249	c->array_index = 0;
250	c->bit_index = 0;
251	c->current_bits = le64_to_cpu(*value);
252
253	return r;
254}
255EXPORT_SYMBOL_GPL(dm_bitset_cursor_begin);
256
257void dm_bitset_cursor_end(struct dm_bitset_cursor *c)
258{
259	return dm_array_cursor_end(&c->cursor);
260}
261EXPORT_SYMBOL_GPL(dm_bitset_cursor_end);
262
263int dm_bitset_cursor_next(struct dm_bitset_cursor *c)
264{
265	int r = 0;
266
267	if (!c->entries_remaining)
268		return -ENODATA;
269
270	c->entries_remaining--;
271	if (++c->bit_index > 63)
272		r = cursor_next_array_entry(c);
273
274	return r;
275}
276EXPORT_SYMBOL_GPL(dm_bitset_cursor_next);
277
278int dm_bitset_cursor_skip(struct dm_bitset_cursor *c, uint32_t count)
279{
280	int r;
281	__le64 *value;
282	uint32_t nr_array_skip;
283	uint32_t remaining_in_word = 64 - c->bit_index;
284
285	if (c->entries_remaining < count)
286		return -ENODATA;
287
288	if (count < remaining_in_word) {
289		c->bit_index += count;
290		c->entries_remaining -= count;
291		return 0;
292
293	} else {
294		c->entries_remaining -= remaining_in_word;
295		count -= remaining_in_word;
296	}
297
298	nr_array_skip = (count / 64) + 1;
299	r = dm_array_cursor_skip(&c->cursor, nr_array_skip);
300	if (r)
301		return r;
302
303	dm_array_cursor_get_value(&c->cursor, (void **) &value);
304	c->entries_remaining -= count;
305	c->array_index += nr_array_skip;
306	c->bit_index = count & 63;
307	c->current_bits = le64_to_cpu(*value);
308
309	return 0;
310}
311EXPORT_SYMBOL_GPL(dm_bitset_cursor_skip);
312
313bool dm_bitset_cursor_get_value(struct dm_bitset_cursor *c)
314{
315	return test_bit(c->bit_index, (unsigned long *) &c->current_bits);
316}
317EXPORT_SYMBOL_GPL(dm_bitset_cursor_get_value);
318
319/*----------------------------------------------------------------*/
320