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51ede0b1 JA |
1 | #include <stdio.h> |
2 | #include <stdlib.h> | |
3 | #include <string.h> | |
4 | #include <assert.h> | |
5 | ||
6 | #include "../arch/arch.h" | |
7 | #include "bitmap.h" | |
8 | #include "../smalloc.h" | |
9 | #include "../minmax.h" | |
10 | ||
11 | #if BITS_PER_LONG == 64 | |
12 | #define UNIT_SIZE 8 | |
13 | #define UNIT_SHIFT 6 | |
14 | #elif BITS_PER_LONG == 32 | |
15 | #define UNIT_SIZE 4 | |
16 | #define UNIT_SHIFT 5 | |
17 | #else | |
18 | #error "Number of arch bits unknown" | |
19 | #endif | |
20 | ||
21 | #define BLOCKS_PER_UNIT (1UL << UNIT_SHIFT) | |
22 | #define BLOCKS_PER_UNIT_MASK (BLOCKS_PER_UNIT - 1) | |
23 | ||
24 | #define firstfree_valid(b) ((b)->first_free != (uint64_t) -1) | |
25 | ||
26 | struct bitmap_level { | |
27 | int level; | |
28 | unsigned long map_size; | |
29 | unsigned long *map; | |
30 | }; | |
31 | ||
32 | struct bitmap { | |
33 | unsigned int nr_levels; | |
34 | struct bitmap_level *levels; | |
35 | uint64_t first_free; | |
36 | }; | |
37 | ||
38 | static unsigned long ulog64(unsigned long val, unsigned int log) | |
39 | { | |
40 | while (log-- && val) | |
41 | val >>= UNIT_SHIFT; | |
42 | ||
43 | return val; | |
44 | } | |
45 | ||
46 | void bitmap_reset(struct bitmap *bitmap) | |
47 | { | |
48 | int i; | |
49 | ||
50 | for (i = 0; i < bitmap->nr_levels; i++) { | |
51 | struct bitmap_level *bl = &bitmap->levels[i]; | |
52 | ||
53 | memset(bl->map, 0, bl->map_size * UNIT_SIZE); | |
54 | } | |
55 | } | |
56 | ||
57 | void bitmap_free(struct bitmap *bitmap) | |
58 | { | |
59 | unsigned int i; | |
60 | ||
61 | if (!bitmap) | |
62 | return; | |
63 | ||
8ba92d11 | 64 | for (i = 0; i < bitmap->nr_levels; i++) |
51ede0b1 | 65 | sfree(bitmap->levels[i].map); |
51ede0b1 JA |
66 | |
67 | sfree(bitmap->levels); | |
68 | sfree(bitmap); | |
69 | } | |
70 | ||
71 | struct bitmap *bitmap_new(unsigned long nr_bits) | |
72 | { | |
73 | struct bitmap *bitmap; | |
74 | unsigned int i, levels; | |
75 | ||
76 | bitmap = smalloc(sizeof(*bitmap)); | |
77 | if (!bitmap) | |
78 | return NULL; | |
79 | ||
80 | levels = 1; | |
81 | i = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
82 | while (i > 1) { | |
83 | i = (i + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
84 | levels++; | |
85 | } | |
86 | ||
87 | bitmap->nr_levels = levels; | |
88 | bitmap->levels = smalloc(bitmap->nr_levels * sizeof(struct bitmap_level)); | |
89 | bitmap->first_free = 0; | |
90 | ||
91 | for (i = 0; i < bitmap->nr_levels; i++) { | |
92 | struct bitmap_level *bl = &bitmap->levels[i]; | |
93 | ||
94 | bl->level = i; | |
95 | bl->map_size = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
96 | bl->map = smalloc(bl->map_size << UNIT_SHIFT); | |
97 | if (!bl->map) | |
98 | goto err; | |
99 | ||
100 | nr_bits = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
101 | } | |
102 | ||
103 | bitmap_reset(bitmap); | |
104 | return bitmap; | |
105 | err: | |
106 | for (i = 0; i < bitmap->nr_levels; i++) | |
107 | if (bitmap->levels[i].map) | |
108 | sfree(bitmap->levels[i].map); | |
109 | ||
110 | sfree(bitmap->levels); | |
111 | return NULL; | |
112 | } | |
113 | ||
114 | static int bitmap_handler(struct bitmap *bitmap, uint64_t bit_nr, | |
115 | int (*func)(struct bitmap_level *, unsigned long, unsigned int, | |
116 | void *), void *data) | |
117 | { | |
118 | struct bitmap_level *bl; | |
119 | int i; | |
120 | ||
121 | for (i = 0; i < bitmap->nr_levels; i++) { | |
122 | unsigned long index = ulog64(bit_nr, i); | |
123 | unsigned long offset = index >> UNIT_SHIFT; | |
124 | unsigned int bit = index & BLOCKS_PER_UNIT_MASK; | |
125 | ||
126 | bl = &bitmap->levels[i]; | |
127 | ||
128 | if (func(bl, offset, bit, data)) | |
129 | return 1; | |
130 | } | |
131 | ||
132 | return 0; | |
133 | } | |
134 | ||
135 | static int bitmap_handler_topdown(struct bitmap *bitmap, uint64_t bit_nr, | |
136 | int (*func)(struct bitmap_level *, unsigned long, unsigned int, void *), | |
137 | void *data) | |
138 | { | |
139 | struct bitmap_level *bl; | |
140 | int i, level = bitmap->nr_levels; | |
141 | ||
142 | for (i = bitmap->nr_levels - 1; i >= 0; i--) { | |
143 | unsigned long index = ulog64(bit_nr, --level); | |
144 | unsigned long offset = index >> UNIT_SHIFT; | |
145 | unsigned int bit = index & BLOCKS_PER_UNIT_MASK; | |
146 | ||
147 | bl = &bitmap->levels[i]; | |
148 | ||
149 | if (func(bl, offset, bit, data)) | |
150 | return 1; | |
151 | } | |
152 | ||
153 | return 0; | |
154 | } | |
155 | ||
156 | static int bitmap_clear_fn(struct bitmap_level *bl, unsigned long offset, | |
157 | unsigned int bit, void *unused) | |
158 | { | |
159 | if (!(bl->map[offset] & (1UL << bit))) | |
160 | return 1; | |
161 | ||
162 | bl->map[offset] &= ~(1UL << bit); | |
163 | return 0; | |
164 | } | |
165 | ||
166 | void bitmap_clear(struct bitmap *bitmap, uint64_t bit_nr) | |
167 | { | |
168 | bitmap_handler(bitmap, bit_nr, bitmap_clear_fn, NULL); | |
169 | } | |
170 | ||
171 | struct bitmap_set_data { | |
172 | unsigned int nr_bits; | |
173 | unsigned int set_bits; | |
174 | unsigned int fail_ok; | |
175 | }; | |
176 | ||
177 | static unsigned long bit_masks[] = { | |
178 | 0x0000000000000000, 0x0000000000000001, 0x0000000000000003, 0x0000000000000007, | |
179 | 0x000000000000000f, 0x000000000000001f, 0x000000000000003f, 0x000000000000007f, | |
180 | 0x00000000000000ff, 0x00000000000001ff, 0x00000000000003ff, 0x00000000000007ff, | |
181 | 0x0000000000000fff, 0x0000000000001fff, 0x0000000000003fff, 0x0000000000007fff, | |
182 | 0x000000000000ffff, 0x000000000001ffff, 0x000000000003ffff, 0x000000000007ffff, | |
183 | 0x00000000000fffff, 0x00000000001fffff, 0x00000000003fffff, 0x00000000007fffff, | |
184 | 0x0000000000ffffff, 0x0000000001ffffff, 0x0000000003ffffff, 0x0000000007ffffff, | |
185 | 0x000000000fffffff, 0x000000001fffffff, 0x000000003fffffff, 0x000000007fffffff, | |
c49715cf JA |
186 | 0x00000000ffffffff, |
187 | #if BITS_PER_LONG == 64 | |
8ba92d11 JA |
188 | 0x00000001ffffffff, 0x00000003ffffffff, 0x00000007ffffffff, 0x0000000fffffffff, |
189 | 0x0000001fffffffff, 0x0000003fffffffff, 0x0000007fffffffff, 0x000000ffffffffff, | |
190 | 0x000001ffffffffff, 0x000003ffffffffff, 0x000007ffffffffff, 0x00000fffffffffff, | |
191 | 0x00001fffffffffff, 0x00003fffffffffff, 0x00007fffffffffff, 0x0000ffffffffffff, | |
192 | 0x0001ffffffffffff, 0x0003ffffffffffff, 0x0007ffffffffffff, 0x000fffffffffffff, | |
193 | 0x001fffffffffffff, 0x003fffffffffffff, 0x007fffffffffffff, 0x00ffffffffffffff, | |
194 | 0x01ffffffffffffff, 0x03ffffffffffffff, 0x07ffffffffffffff, 0x0fffffffffffffff, | |
195 | 0x1fffffffffffffff, 0x3fffffffffffffff, 0x7fffffffffffffff, 0xffffffffffffffff | |
c49715cf JA |
196 | #endif |
197 | }; | |
51ede0b1 JA |
198 | |
199 | static int bitmap_set_fn(struct bitmap_level *bl, unsigned long offset, | |
200 | unsigned int bit, void *__data) | |
201 | { | |
202 | struct bitmap_set_data *data = __data; | |
203 | unsigned long mask, overlap; | |
204 | unsigned int nr_bits; | |
205 | ||
206 | nr_bits = min(data->nr_bits, BLOCKS_PER_UNIT - bit); | |
207 | ||
208 | mask = bit_masks[nr_bits] << bit; | |
209 | ||
210 | /* | |
211 | * Mask off any potential overlap, only sets contig regions | |
212 | */ | |
213 | overlap = bl->map[offset] & mask; | |
214 | if (overlap == mask) { | |
215 | assert(data->fail_ok); | |
216 | return 1; | |
217 | } | |
218 | ||
219 | while (overlap) { | |
220 | unsigned long clear_mask = ~(1UL << ffz(~overlap)); | |
221 | ||
222 | mask &= clear_mask; | |
223 | overlap &= clear_mask; | |
224 | nr_bits--; | |
225 | } | |
226 | ||
227 | assert(mask); | |
228 | assert(!(bl->map[offset] & mask)); | |
229 | ||
230 | bl->map[offset] |= mask; | |
231 | ||
232 | if (!bl->level) | |
233 | data->set_bits = nr_bits; | |
234 | ||
235 | data->nr_bits = 1; | |
236 | return bl->map[offset] != -1UL; | |
237 | } | |
238 | ||
239 | static void __bitmap_set(struct bitmap *bitmap, uint64_t bit_nr, | |
240 | struct bitmap_set_data *data) | |
241 | { | |
242 | unsigned int set_bits, nr_bits = data->nr_bits; | |
243 | ||
244 | if (bitmap->first_free >= bit_nr && | |
245 | bitmap->first_free < bit_nr + data->nr_bits) | |
246 | bitmap->first_free = -1ULL; | |
247 | ||
248 | set_bits = 0; | |
249 | while (nr_bits) { | |
250 | bitmap_handler(bitmap, bit_nr, bitmap_set_fn, data); | |
251 | set_bits += data->set_bits; | |
252 | ||
253 | if (data->set_bits != (BLOCKS_PER_UNIT - nr_bits)) | |
254 | break; | |
255 | ||
256 | nr_bits -= data->set_bits; | |
257 | bit_nr += data->set_bits; | |
258 | ||
259 | data->nr_bits = nr_bits; | |
260 | data->fail_ok = 1; | |
261 | } | |
262 | ||
263 | data->set_bits = set_bits; | |
264 | } | |
265 | ||
266 | void bitmap_set(struct bitmap *bitmap, uint64_t bit_nr) | |
267 | { | |
268 | struct bitmap_set_data data = { .nr_bits = 1, }; | |
269 | ||
270 | __bitmap_set(bitmap, bit_nr, &data); | |
271 | } | |
272 | ||
273 | unsigned int bitmap_set_nr(struct bitmap *bitmap, uint64_t bit_nr, unsigned int nr_bits) | |
274 | { | |
275 | struct bitmap_set_data data = { .nr_bits = nr_bits, }; | |
276 | ||
277 | __bitmap_set(bitmap, bit_nr, &data); | |
278 | return data.set_bits; | |
279 | } | |
280 | ||
281 | static int bitmap_isset_fn(struct bitmap_level *bl, unsigned long offset, | |
282 | unsigned int bit, void *unused) | |
283 | { | |
284 | return (bl->map[offset] & (1UL << bit)) != 0; | |
285 | } | |
286 | ||
287 | int bitmap_isset(struct bitmap *bitmap, uint64_t bit_nr) | |
288 | { | |
289 | return bitmap_handler_topdown(bitmap, bit_nr, bitmap_isset_fn, NULL); | |
290 | } | |
291 | ||
292 | static uint64_t bitmap_find_first_free(struct bitmap *bitmap, unsigned int level, | |
293 | uint64_t index) | |
294 | { | |
295 | unsigned long j; | |
296 | int i; | |
297 | ||
298 | /* | |
299 | * Start at the bottom, then converge towards first free bit at the top | |
300 | */ | |
301 | for (i = level; i >= 0; i--) { | |
302 | struct bitmap_level *bl = &bitmap->levels[i]; | |
303 | ||
304 | if (index >= bl->map_size) { | |
305 | index = -1ULL; | |
306 | break; | |
307 | } | |
308 | ||
309 | for (j = index; j < bl->map_size; j++) { | |
310 | if (bl->map[j] == -1UL) | |
311 | continue; | |
312 | ||
313 | /* | |
314 | * First free bit here is our index into the first | |
315 | * free bit at the next higher level | |
316 | */ | |
317 | index = (j << UNIT_SHIFT) + ffz(bl->map[j]); | |
318 | break; | |
319 | } | |
320 | } | |
321 | ||
322 | return index; | |
323 | } | |
324 | ||
325 | uint64_t bitmap_first_free(struct bitmap *bitmap) | |
326 | { | |
327 | if (firstfree_valid(bitmap)) | |
328 | return bitmap->first_free; | |
329 | ||
330 | bitmap->first_free = bitmap_find_first_free(bitmap, bitmap->nr_levels - 1, 0); | |
331 | return bitmap->first_free; | |
332 | } | |
333 | ||
334 | struct bitmap_next_free_data { | |
335 | unsigned int level; | |
336 | unsigned long offset; | |
337 | uint64_t bit; | |
338 | }; | |
339 | ||
340 | static int bitmap_next_free_fn(struct bitmap_level *bl, unsigned long offset, | |
341 | unsigned int bit, void *__data) | |
342 | { | |
343 | struct bitmap_next_free_data *data = __data; | |
344 | uint64_t mask = ~((1UL << ((data->bit & BLOCKS_PER_UNIT_MASK) + 1)) - 1); | |
345 | ||
346 | if (!(mask & bl->map[offset])) | |
347 | return 0; | |
348 | ||
349 | if (bl->map[offset] != -1UL) { | |
350 | data->level = bl->level; | |
351 | data->offset = offset; | |
352 | return 1; | |
353 | } | |
354 | ||
355 | data->bit = (data->bit + BLOCKS_PER_UNIT - 1) / BLOCKS_PER_UNIT; | |
356 | return 0; | |
357 | } | |
358 | ||
359 | /* | |
360 | * 'bit_nr' is already set. Find the next free bit after this one. | |
361 | */ | |
362 | uint64_t bitmap_next_free(struct bitmap *bitmap, uint64_t bit_nr) | |
363 | { | |
364 | struct bitmap_next_free_data data = { .level = -1U, .bit = bit_nr, }; | |
365 | ||
366 | if (firstfree_valid(bitmap) && bit_nr < bitmap->first_free) | |
367 | return bitmap->first_free; | |
368 | ||
369 | if (!bitmap_handler(bitmap, bit_nr, bitmap_next_free_fn, &data)) | |
370 | return bitmap_first_free(bitmap); | |
371 | ||
372 | assert(data.level != -1U); | |
373 | ||
374 | return bitmap_find_first_free(bitmap, data.level, data.offset); | |
375 | } |