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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 | ||
64 | for (i = 0; i < bitmap->nr_levels; i++) { | |
65 | #if 0 | |
66 | unsigned long j; | |
67 | ||
68 | for (j = 0; j < bitmap->levels[i].map_size; j++) { | |
69 | if (bitmap->levels[i].map[j] != ~0UL) | |
70 | printf("L%d: %.5ld=%.16lx\n", i, j, bitmap->levels[i].map[j]); | |
71 | } | |
72 | #endif | |
73 | ||
74 | sfree(bitmap->levels[i].map); | |
75 | } | |
76 | ||
77 | sfree(bitmap->levels); | |
78 | sfree(bitmap); | |
79 | } | |
80 | ||
81 | struct bitmap *bitmap_new(unsigned long nr_bits) | |
82 | { | |
83 | struct bitmap *bitmap; | |
84 | unsigned int i, levels; | |
85 | ||
86 | bitmap = smalloc(sizeof(*bitmap)); | |
87 | if (!bitmap) | |
88 | return NULL; | |
89 | ||
90 | levels = 1; | |
91 | i = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
92 | while (i > 1) { | |
93 | i = (i + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
94 | levels++; | |
95 | } | |
96 | ||
97 | bitmap->nr_levels = levels; | |
98 | bitmap->levels = smalloc(bitmap->nr_levels * sizeof(struct bitmap_level)); | |
99 | bitmap->first_free = 0; | |
100 | ||
101 | for (i = 0; i < bitmap->nr_levels; i++) { | |
102 | struct bitmap_level *bl = &bitmap->levels[i]; | |
103 | ||
104 | bl->level = i; | |
105 | bl->map_size = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
106 | bl->map = smalloc(bl->map_size << UNIT_SHIFT); | |
107 | if (!bl->map) | |
108 | goto err; | |
109 | ||
110 | nr_bits = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
111 | } | |
112 | ||
113 | bitmap_reset(bitmap); | |
114 | return bitmap; | |
115 | err: | |
116 | for (i = 0; i < bitmap->nr_levels; i++) | |
117 | if (bitmap->levels[i].map) | |
118 | sfree(bitmap->levels[i].map); | |
119 | ||
120 | sfree(bitmap->levels); | |
121 | return NULL; | |
122 | } | |
123 | ||
124 | static int bitmap_handler(struct bitmap *bitmap, uint64_t bit_nr, | |
125 | int (*func)(struct bitmap_level *, unsigned long, unsigned int, | |
126 | void *), void *data) | |
127 | { | |
128 | struct bitmap_level *bl; | |
129 | int i; | |
130 | ||
131 | for (i = 0; i < bitmap->nr_levels; i++) { | |
132 | unsigned long index = ulog64(bit_nr, i); | |
133 | unsigned long offset = index >> UNIT_SHIFT; | |
134 | unsigned int bit = index & BLOCKS_PER_UNIT_MASK; | |
135 | ||
136 | bl = &bitmap->levels[i]; | |
137 | ||
138 | if (func(bl, offset, bit, data)) | |
139 | return 1; | |
140 | } | |
141 | ||
142 | return 0; | |
143 | } | |
144 | ||
145 | static int bitmap_handler_topdown(struct bitmap *bitmap, uint64_t bit_nr, | |
146 | int (*func)(struct bitmap_level *, unsigned long, unsigned int, void *), | |
147 | void *data) | |
148 | { | |
149 | struct bitmap_level *bl; | |
150 | int i, level = bitmap->nr_levels; | |
151 | ||
152 | for (i = bitmap->nr_levels - 1; i >= 0; i--) { | |
153 | unsigned long index = ulog64(bit_nr, --level); | |
154 | unsigned long offset = index >> UNIT_SHIFT; | |
155 | unsigned int bit = index & BLOCKS_PER_UNIT_MASK; | |
156 | ||
157 | bl = &bitmap->levels[i]; | |
158 | ||
159 | if (func(bl, offset, bit, data)) | |
160 | return 1; | |
161 | } | |
162 | ||
163 | return 0; | |
164 | } | |
165 | ||
166 | static int bitmap_clear_fn(struct bitmap_level *bl, unsigned long offset, | |
167 | unsigned int bit, void *unused) | |
168 | { | |
169 | if (!(bl->map[offset] & (1UL << bit))) | |
170 | return 1; | |
171 | ||
172 | bl->map[offset] &= ~(1UL << bit); | |
173 | return 0; | |
174 | } | |
175 | ||
176 | void bitmap_clear(struct bitmap *bitmap, uint64_t bit_nr) | |
177 | { | |
178 | bitmap_handler(bitmap, bit_nr, bitmap_clear_fn, NULL); | |
179 | } | |
180 | ||
181 | struct bitmap_set_data { | |
182 | unsigned int nr_bits; | |
183 | unsigned int set_bits; | |
184 | unsigned int fail_ok; | |
185 | }; | |
186 | ||
187 | static unsigned long bit_masks[] = { | |
188 | 0x0000000000000000, 0x0000000000000001, 0x0000000000000003, 0x0000000000000007, | |
189 | 0x000000000000000f, 0x000000000000001f, 0x000000000000003f, 0x000000000000007f, | |
190 | 0x00000000000000ff, 0x00000000000001ff, 0x00000000000003ff, 0x00000000000007ff, | |
191 | 0x0000000000000fff, 0x0000000000001fff, 0x0000000000003fff, 0x0000000000007fff, | |
192 | 0x000000000000ffff, 0x000000000001ffff, 0x000000000003ffff, 0x000000000007ffff, | |
193 | 0x00000000000fffff, 0x00000000001fffff, 0x00000000003fffff, 0x00000000007fffff, | |
194 | 0x0000000000ffffff, 0x0000000001ffffff, 0x0000000003ffffff, 0x0000000007ffffff, | |
195 | 0x000000000fffffff, 0x000000001fffffff, 0x000000003fffffff, 0x000000007fffffff, | |
c49715cf JA |
196 | 0x00000000ffffffff, |
197 | #if BITS_PER_LONG == 64 | |
198 | 0x00000001ffffffff, 0x00000003ffffffff, 0x00000007ffffffff, | |
51ede0b1 JA |
199 | 0x0000000fffffffff, 0x0000001fffffffff, 0x0000003fffffffff, 0x0000007fffffffff, |
200 | 0x000000ffffffffff, 0x000001ffffffffff, 0x000003ffffffffff, 0x000007ffffffffff, | |
201 | 0x00000fffffffffff, 0x00001fffffffffff, 0x00003fffffffffff, 0x00007fffffffffff, | |
202 | 0x0000ffffffffffff, 0x0001ffffffffffff, 0x0003ffffffffffff, 0x0007ffffffffffff, | |
203 | 0x000fffffffffffff, 0x001fffffffffffff, 0x003fffffffffffff, 0x007fffffffffffff, | |
204 | 0x00ffffffffffffff, 0x01ffffffffffffff, 0x03ffffffffffffff, 0x07ffffffffffffff, | |
205 | 0x0fffffffffffffff, 0x1fffffffffffffff, 0x3fffffffffffffff, 0x7fffffffffffffff, | |
c49715cf JA |
206 | 0xffffffffffffffff |
207 | #endif | |
208 | }; | |
51ede0b1 JA |
209 | |
210 | static int bitmap_set_fn(struct bitmap_level *bl, unsigned long offset, | |
211 | unsigned int bit, void *__data) | |
212 | { | |
213 | struct bitmap_set_data *data = __data; | |
214 | unsigned long mask, overlap; | |
215 | unsigned int nr_bits; | |
216 | ||
217 | nr_bits = min(data->nr_bits, BLOCKS_PER_UNIT - bit); | |
218 | ||
219 | mask = bit_masks[nr_bits] << bit; | |
220 | ||
221 | /* | |
222 | * Mask off any potential overlap, only sets contig regions | |
223 | */ | |
224 | overlap = bl->map[offset] & mask; | |
225 | if (overlap == mask) { | |
226 | assert(data->fail_ok); | |
227 | return 1; | |
228 | } | |
229 | ||
230 | while (overlap) { | |
231 | unsigned long clear_mask = ~(1UL << ffz(~overlap)); | |
232 | ||
233 | mask &= clear_mask; | |
234 | overlap &= clear_mask; | |
235 | nr_bits--; | |
236 | } | |
237 | ||
238 | assert(mask); | |
239 | assert(!(bl->map[offset] & mask)); | |
240 | ||
241 | bl->map[offset] |= mask; | |
242 | ||
243 | if (!bl->level) | |
244 | data->set_bits = nr_bits; | |
245 | ||
246 | data->nr_bits = 1; | |
247 | return bl->map[offset] != -1UL; | |
248 | } | |
249 | ||
250 | static void __bitmap_set(struct bitmap *bitmap, uint64_t bit_nr, | |
251 | struct bitmap_set_data *data) | |
252 | { | |
253 | unsigned int set_bits, nr_bits = data->nr_bits; | |
254 | ||
255 | if (bitmap->first_free >= bit_nr && | |
256 | bitmap->first_free < bit_nr + data->nr_bits) | |
257 | bitmap->first_free = -1ULL; | |
258 | ||
259 | set_bits = 0; | |
260 | while (nr_bits) { | |
261 | bitmap_handler(bitmap, bit_nr, bitmap_set_fn, data); | |
262 | set_bits += data->set_bits; | |
263 | ||
264 | if (data->set_bits != (BLOCKS_PER_UNIT - nr_bits)) | |
265 | break; | |
266 | ||
267 | nr_bits -= data->set_bits; | |
268 | bit_nr += data->set_bits; | |
269 | ||
270 | data->nr_bits = nr_bits; | |
271 | data->fail_ok = 1; | |
272 | } | |
273 | ||
274 | data->set_bits = set_bits; | |
275 | } | |
276 | ||
277 | void bitmap_set(struct bitmap *bitmap, uint64_t bit_nr) | |
278 | { | |
279 | struct bitmap_set_data data = { .nr_bits = 1, }; | |
280 | ||
281 | __bitmap_set(bitmap, bit_nr, &data); | |
282 | } | |
283 | ||
284 | unsigned int bitmap_set_nr(struct bitmap *bitmap, uint64_t bit_nr, unsigned int nr_bits) | |
285 | { | |
286 | struct bitmap_set_data data = { .nr_bits = nr_bits, }; | |
287 | ||
288 | __bitmap_set(bitmap, bit_nr, &data); | |
289 | return data.set_bits; | |
290 | } | |
291 | ||
292 | static int bitmap_isset_fn(struct bitmap_level *bl, unsigned long offset, | |
293 | unsigned int bit, void *unused) | |
294 | { | |
295 | return (bl->map[offset] & (1UL << bit)) != 0; | |
296 | } | |
297 | ||
298 | int bitmap_isset(struct bitmap *bitmap, uint64_t bit_nr) | |
299 | { | |
300 | return bitmap_handler_topdown(bitmap, bit_nr, bitmap_isset_fn, NULL); | |
301 | } | |
302 | ||
303 | static uint64_t bitmap_find_first_free(struct bitmap *bitmap, unsigned int level, | |
304 | uint64_t index) | |
305 | { | |
306 | unsigned long j; | |
307 | int i; | |
308 | ||
309 | /* | |
310 | * Start at the bottom, then converge towards first free bit at the top | |
311 | */ | |
312 | for (i = level; i >= 0; i--) { | |
313 | struct bitmap_level *bl = &bitmap->levels[i]; | |
314 | ||
315 | if (index >= bl->map_size) { | |
316 | index = -1ULL; | |
317 | break; | |
318 | } | |
319 | ||
320 | for (j = index; j < bl->map_size; j++) { | |
321 | if (bl->map[j] == -1UL) | |
322 | continue; | |
323 | ||
324 | /* | |
325 | * First free bit here is our index into the first | |
326 | * free bit at the next higher level | |
327 | */ | |
328 | index = (j << UNIT_SHIFT) + ffz(bl->map[j]); | |
329 | break; | |
330 | } | |
331 | } | |
332 | ||
333 | return index; | |
334 | } | |
335 | ||
336 | uint64_t bitmap_first_free(struct bitmap *bitmap) | |
337 | { | |
338 | if (firstfree_valid(bitmap)) | |
339 | return bitmap->first_free; | |
340 | ||
341 | bitmap->first_free = bitmap_find_first_free(bitmap, bitmap->nr_levels - 1, 0); | |
342 | return bitmap->first_free; | |
343 | } | |
344 | ||
345 | struct bitmap_next_free_data { | |
346 | unsigned int level; | |
347 | unsigned long offset; | |
348 | uint64_t bit; | |
349 | }; | |
350 | ||
351 | static int bitmap_next_free_fn(struct bitmap_level *bl, unsigned long offset, | |
352 | unsigned int bit, void *__data) | |
353 | { | |
354 | struct bitmap_next_free_data *data = __data; | |
355 | uint64_t mask = ~((1UL << ((data->bit & BLOCKS_PER_UNIT_MASK) + 1)) - 1); | |
356 | ||
357 | if (!(mask & bl->map[offset])) | |
358 | return 0; | |
359 | ||
360 | if (bl->map[offset] != -1UL) { | |
361 | data->level = bl->level; | |
362 | data->offset = offset; | |
363 | return 1; | |
364 | } | |
365 | ||
366 | data->bit = (data->bit + BLOCKS_PER_UNIT - 1) / BLOCKS_PER_UNIT; | |
367 | return 0; | |
368 | } | |
369 | ||
370 | /* | |
371 | * 'bit_nr' is already set. Find the next free bit after this one. | |
372 | */ | |
373 | uint64_t bitmap_next_free(struct bitmap *bitmap, uint64_t bit_nr) | |
374 | { | |
375 | struct bitmap_next_free_data data = { .level = -1U, .bit = bit_nr, }; | |
376 | ||
377 | if (firstfree_valid(bitmap) && bit_nr < bitmap->first_free) | |
378 | return bitmap->first_free; | |
379 | ||
380 | if (!bitmap_handler(bitmap, bit_nr, bitmap_next_free_fn, &data)) | |
381 | return bitmap_first_free(bitmap); | |
382 | ||
383 | assert(data.level != -1U); | |
384 | ||
385 | return bitmap_find_first_free(bitmap, data.level, data.offset); | |
386 | } |