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 
19 static 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 
29 void 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 }
35 EXPORT_SYMBOL_GPL(dm_disk_bitset_init);
36 
37 int dm_bitset_empty(struct dm_disk_bitset *info, dm_block_t *root)
38 {
39 	return dm_array_empty(&info->array_info, root);
40 }
41 EXPORT_SYMBOL_GPL(dm_bitset_empty);
42 
43 struct packer_context {
44 	bit_value_fn fn;
45 	unsigned int nr_bits;
46 	void *context;
47 };
48 
49 static 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 
73 int 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 }
84 EXPORT_SYMBOL_GPL(dm_bitset_new);
85 
86 int 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 }
98 EXPORT_SYMBOL_GPL(dm_bitset_resize);
99 
100 int dm_bitset_del(struct dm_disk_bitset *info, dm_block_t root)
101 {
102 	return dm_array_del(&info->array_info, root);
103 }
104 EXPORT_SYMBOL_GPL(dm_bitset_del);
105 
106 int 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 }
128 EXPORT_SYMBOL_GPL(dm_bitset_flush);
129 
130 static 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 
148 static 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 
166 int 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 }
181 EXPORT_SYMBOL_GPL(dm_bitset_set_bit);
182 
183 int 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 }
198 EXPORT_SYMBOL_GPL(dm_bitset_clear_bit);
199 
200 int 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 }
213 EXPORT_SYMBOL_GPL(dm_bitset_test_bit);
214 
215 static 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 
231 int 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 }
255 EXPORT_SYMBOL_GPL(dm_bitset_cursor_begin);
256 
257 void dm_bitset_cursor_end(struct dm_bitset_cursor *c)
258 {
259 	return dm_array_cursor_end(&c->cursor);
260 }
261 EXPORT_SYMBOL_GPL(dm_bitset_cursor_end);
262 
263 int 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 }
276 EXPORT_SYMBOL_GPL(dm_bitset_cursor_next);
277 
278 int 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 }
311 EXPORT_SYMBOL_GPL(dm_bitset_cursor_skip);
312 
313 bool dm_bitset_cursor_get_value(struct dm_bitset_cursor *c)
314 {
315 	return test_bit(c->bit_index, (unsigned long *) &c->current_bits);
316 }
317 EXPORT_SYMBOL_GPL(dm_bitset_cursor_get_value);
318 
319 /*----------------------------------------------------------------*/
320