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1 | // SPDX-License-Identifier: GPL-2.0-only | |
2 | /* | |
3 | * lib/bitmap.c | |
4 | * Helper functions for bitmap.h. | |
5 | */ | |
6 | ||
7 | #include <linux/bitmap.h> | |
8 | #include <linux/bitops.h> | |
9 | #include <linux/ctype.h> | |
10 | #include <linux/device.h> | |
11 | #include <linux/export.h> | |
12 | #include <linux/slab.h> | |
13 | ||
14 | /** | |
15 | * DOC: bitmap introduction | |
16 | * | |
17 | * bitmaps provide an array of bits, implemented using an | |
18 | * array of unsigned longs. The number of valid bits in a | |
19 | * given bitmap does _not_ need to be an exact multiple of | |
20 | * BITS_PER_LONG. | |
21 | * | |
22 | * The possible unused bits in the last, partially used word | |
23 | * of a bitmap are 'don't care'. The implementation makes | |
24 | * no particular effort to keep them zero. It ensures that | |
25 | * their value will not affect the results of any operation. | |
26 | * The bitmap operations that return Boolean (bitmap_empty, | |
27 | * for example) or scalar (bitmap_weight, for example) results | |
28 | * carefully filter out these unused bits from impacting their | |
29 | * results. | |
30 | * | |
31 | * The byte ordering of bitmaps is more natural on little | |
32 | * endian architectures. See the big-endian headers | |
33 | * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h | |
34 | * for the best explanations of this ordering. | |
35 | */ | |
36 | ||
37 | bool __bitmap_equal(const unsigned long *bitmap1, | |
38 | const unsigned long *bitmap2, unsigned int bits) | |
39 | { | |
40 | unsigned int k, lim = bits/BITS_PER_LONG; | |
41 | for (k = 0; k < lim; ++k) | |
42 | if (bitmap1[k] != bitmap2[k]) | |
43 | return false; | |
44 | ||
45 | if (bits % BITS_PER_LONG) | |
46 | if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) | |
47 | return false; | |
48 | ||
49 | return true; | |
50 | } | |
51 | EXPORT_SYMBOL(__bitmap_equal); | |
52 | ||
53 | bool __bitmap_or_equal(const unsigned long *bitmap1, | |
54 | const unsigned long *bitmap2, | |
55 | const unsigned long *bitmap3, | |
56 | unsigned int bits) | |
57 | { | |
58 | unsigned int k, lim = bits / BITS_PER_LONG; | |
59 | unsigned long tmp; | |
60 | ||
61 | for (k = 0; k < lim; ++k) { | |
62 | if ((bitmap1[k] | bitmap2[k]) != bitmap3[k]) | |
63 | return false; | |
64 | } | |
65 | ||
66 | if (!(bits % BITS_PER_LONG)) | |
67 | return true; | |
68 | ||
69 | tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k]; | |
70 | return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0; | |
71 | } | |
72 | ||
73 | void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits) | |
74 | { | |
75 | unsigned int k, lim = BITS_TO_LONGS(bits); | |
76 | for (k = 0; k < lim; ++k) | |
77 | dst[k] = ~src[k]; | |
78 | } | |
79 | EXPORT_SYMBOL(__bitmap_complement); | |
80 | ||
81 | /** | |
82 | * __bitmap_shift_right - logical right shift of the bits in a bitmap | |
83 | * @dst : destination bitmap | |
84 | * @src : source bitmap | |
85 | * @shift : shift by this many bits | |
86 | * @nbits : bitmap size, in bits | |
87 | * | |
88 | * Shifting right (dividing) means moving bits in the MS -> LS bit | |
89 | * direction. Zeros are fed into the vacated MS positions and the | |
90 | * LS bits shifted off the bottom are lost. | |
91 | */ | |
92 | void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, | |
93 | unsigned shift, unsigned nbits) | |
94 | { | |
95 | unsigned k, lim = BITS_TO_LONGS(nbits); | |
96 | unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; | |
97 | unsigned long mask = BITMAP_LAST_WORD_MASK(nbits); | |
98 | for (k = 0; off + k < lim; ++k) { | |
99 | unsigned long upper, lower; | |
100 | ||
101 | /* | |
102 | * If shift is not word aligned, take lower rem bits of | |
103 | * word above and make them the top rem bits of result. | |
104 | */ | |
105 | if (!rem || off + k + 1 >= lim) | |
106 | upper = 0; | |
107 | else { | |
108 | upper = src[off + k + 1]; | |
109 | if (off + k + 1 == lim - 1) | |
110 | upper &= mask; | |
111 | upper <<= (BITS_PER_LONG - rem); | |
112 | } | |
113 | lower = src[off + k]; | |
114 | if (off + k == lim - 1) | |
115 | lower &= mask; | |
116 | lower >>= rem; | |
117 | dst[k] = lower | upper; | |
118 | } | |
119 | if (off) | |
120 | memset(&dst[lim - off], 0, off*sizeof(unsigned long)); | |
121 | } | |
122 | EXPORT_SYMBOL(__bitmap_shift_right); | |
123 | ||
124 | ||
125 | /** | |
126 | * __bitmap_shift_left - logical left shift of the bits in a bitmap | |
127 | * @dst : destination bitmap | |
128 | * @src : source bitmap | |
129 | * @shift : shift by this many bits | |
130 | * @nbits : bitmap size, in bits | |
131 | * | |
132 | * Shifting left (multiplying) means moving bits in the LS -> MS | |
133 | * direction. Zeros are fed into the vacated LS bit positions | |
134 | * and those MS bits shifted off the top are lost. | |
135 | */ | |
136 | ||
137 | void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, | |
138 | unsigned int shift, unsigned int nbits) | |
139 | { | |
140 | int k; | |
141 | unsigned int lim = BITS_TO_LONGS(nbits); | |
142 | unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; | |
143 | for (k = lim - off - 1; k >= 0; --k) { | |
144 | unsigned long upper, lower; | |
145 | ||
146 | /* | |
147 | * If shift is not word aligned, take upper rem bits of | |
148 | * word below and make them the bottom rem bits of result. | |
149 | */ | |
150 | if (rem && k > 0) | |
151 | lower = src[k - 1] >> (BITS_PER_LONG - rem); | |
152 | else | |
153 | lower = 0; | |
154 | upper = src[k] << rem; | |
155 | dst[k + off] = lower | upper; | |
156 | } | |
157 | if (off) | |
158 | memset(dst, 0, off*sizeof(unsigned long)); | |
159 | } | |
160 | EXPORT_SYMBOL(__bitmap_shift_left); | |
161 | ||
162 | /** | |
163 | * bitmap_cut() - remove bit region from bitmap and right shift remaining bits | |
164 | * @dst: destination bitmap, might overlap with src | |
165 | * @src: source bitmap | |
166 | * @first: start bit of region to be removed | |
167 | * @cut: number of bits to remove | |
168 | * @nbits: bitmap size, in bits | |
169 | * | |
170 | * Set the n-th bit of @dst iff the n-th bit of @src is set and | |
171 | * n is less than @first, or the m-th bit of @src is set for any | |
172 | * m such that @first <= n < nbits, and m = n + @cut. | |
173 | * | |
174 | * In pictures, example for a big-endian 32-bit architecture: | |
175 | * | |
176 | * The @src bitmap is:: | |
177 | * | |
178 | * 31 63 | |
179 | * | | | |
180 | * 10000000 11000001 11110010 00010101 10000000 11000001 01110010 00010101 | |
181 | * | | | | | |
182 | * 16 14 0 32 | |
183 | * | |
184 | * if @cut is 3, and @first is 14, bits 14-16 in @src are cut and @dst is:: | |
185 | * | |
186 | * 31 63 | |
187 | * | | | |
188 | * 10110000 00011000 00110010 00010101 00010000 00011000 00101110 01000010 | |
189 | * | | | | |
190 | * 14 (bit 17 0 32 | |
191 | * from @src) | |
192 | * | |
193 | * Note that @dst and @src might overlap partially or entirely. | |
194 | * | |
195 | * This is implemented in the obvious way, with a shift and carry | |
196 | * step for each moved bit. Optimisation is left as an exercise | |
197 | * for the compiler. | |
198 | */ | |
199 | void bitmap_cut(unsigned long *dst, const unsigned long *src, | |
200 | unsigned int first, unsigned int cut, unsigned int nbits) | |
201 | { | |
202 | unsigned int len = BITS_TO_LONGS(nbits); | |
203 | unsigned long keep = 0, carry; | |
204 | int i; | |
205 | ||
206 | if (first % BITS_PER_LONG) { | |
207 | keep = src[first / BITS_PER_LONG] & | |
208 | (~0UL >> (BITS_PER_LONG - first % BITS_PER_LONG)); | |
209 | } | |
210 | ||
211 | memmove(dst, src, len * sizeof(*dst)); | |
212 | ||
213 | while (cut--) { | |
214 | for (i = first / BITS_PER_LONG; i < len; i++) { | |
215 | if (i < len - 1) | |
216 | carry = dst[i + 1] & 1UL; | |
217 | else | |
218 | carry = 0; | |
219 | ||
220 | dst[i] = (dst[i] >> 1) | (carry << (BITS_PER_LONG - 1)); | |
221 | } | |
222 | } | |
223 | ||
224 | dst[first / BITS_PER_LONG] &= ~0UL << (first % BITS_PER_LONG); | |
225 | dst[first / BITS_PER_LONG] |= keep; | |
226 | } | |
227 | EXPORT_SYMBOL(bitmap_cut); | |
228 | ||
229 | bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, | |
230 | const unsigned long *bitmap2, unsigned int bits) | |
231 | { | |
232 | unsigned int k; | |
233 | unsigned int lim = bits/BITS_PER_LONG; | |
234 | unsigned long result = 0; | |
235 | ||
236 | for (k = 0; k < lim; k++) | |
237 | result |= (dst[k] = bitmap1[k] & bitmap2[k]); | |
238 | if (bits % BITS_PER_LONG) | |
239 | result |= (dst[k] = bitmap1[k] & bitmap2[k] & | |
240 | BITMAP_LAST_WORD_MASK(bits)); | |
241 | return result != 0; | |
242 | } | |
243 | EXPORT_SYMBOL(__bitmap_and); | |
244 | ||
245 | void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, | |
246 | const unsigned long *bitmap2, unsigned int bits) | |
247 | { | |
248 | unsigned int k; | |
249 | unsigned int nr = BITS_TO_LONGS(bits); | |
250 | ||
251 | for (k = 0; k < nr; k++) | |
252 | dst[k] = bitmap1[k] | bitmap2[k]; | |
253 | } | |
254 | EXPORT_SYMBOL(__bitmap_or); | |
255 | ||
256 | void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, | |
257 | const unsigned long *bitmap2, unsigned int bits) | |
258 | { | |
259 | unsigned int k; | |
260 | unsigned int nr = BITS_TO_LONGS(bits); | |
261 | ||
262 | for (k = 0; k < nr; k++) | |
263 | dst[k] = bitmap1[k] ^ bitmap2[k]; | |
264 | } | |
265 | EXPORT_SYMBOL(__bitmap_xor); | |
266 | ||
267 | bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, | |
268 | const unsigned long *bitmap2, unsigned int bits) | |
269 | { | |
270 | unsigned int k; | |
271 | unsigned int lim = bits/BITS_PER_LONG; | |
272 | unsigned long result = 0; | |
273 | ||
274 | for (k = 0; k < lim; k++) | |
275 | result |= (dst[k] = bitmap1[k] & ~bitmap2[k]); | |
276 | if (bits % BITS_PER_LONG) | |
277 | result |= (dst[k] = bitmap1[k] & ~bitmap2[k] & | |
278 | BITMAP_LAST_WORD_MASK(bits)); | |
279 | return result != 0; | |
280 | } | |
281 | EXPORT_SYMBOL(__bitmap_andnot); | |
282 | ||
283 | void __bitmap_replace(unsigned long *dst, | |
284 | const unsigned long *old, const unsigned long *new, | |
285 | const unsigned long *mask, unsigned int nbits) | |
286 | { | |
287 | unsigned int k; | |
288 | unsigned int nr = BITS_TO_LONGS(nbits); | |
289 | ||
290 | for (k = 0; k < nr; k++) | |
291 | dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]); | |
292 | } | |
293 | EXPORT_SYMBOL(__bitmap_replace); | |
294 | ||
295 | bool __bitmap_intersects(const unsigned long *bitmap1, | |
296 | const unsigned long *bitmap2, unsigned int bits) | |
297 | { | |
298 | unsigned int k, lim = bits/BITS_PER_LONG; | |
299 | for (k = 0; k < lim; ++k) | |
300 | if (bitmap1[k] & bitmap2[k]) | |
301 | return true; | |
302 | ||
303 | if (bits % BITS_PER_LONG) | |
304 | if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) | |
305 | return true; | |
306 | return false; | |
307 | } | |
308 | EXPORT_SYMBOL(__bitmap_intersects); | |
309 | ||
310 | bool __bitmap_subset(const unsigned long *bitmap1, | |
311 | const unsigned long *bitmap2, unsigned int bits) | |
312 | { | |
313 | unsigned int k, lim = bits/BITS_PER_LONG; | |
314 | for (k = 0; k < lim; ++k) | |
315 | if (bitmap1[k] & ~bitmap2[k]) | |
316 | return false; | |
317 | ||
318 | if (bits % BITS_PER_LONG) | |
319 | if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) | |
320 | return false; | |
321 | return true; | |
322 | } | |
323 | EXPORT_SYMBOL(__bitmap_subset); | |
324 | ||
325 | #define BITMAP_WEIGHT(FETCH, bits) \ | |
326 | ({ \ | |
327 | unsigned int __bits = (bits), idx, w = 0; \ | |
328 | \ | |
329 | for (idx = 0; idx < __bits / BITS_PER_LONG; idx++) \ | |
330 | w += hweight_long(FETCH); \ | |
331 | \ | |
332 | if (__bits % BITS_PER_LONG) \ | |
333 | w += hweight_long((FETCH) & BITMAP_LAST_WORD_MASK(__bits)); \ | |
334 | \ | |
335 | w; \ | |
336 | }) | |
337 | ||
338 | unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) | |
339 | { | |
340 | return BITMAP_WEIGHT(bitmap[idx], bits); | |
341 | } | |
342 | EXPORT_SYMBOL(__bitmap_weight); | |
343 | ||
344 | unsigned int __bitmap_weight_and(const unsigned long *bitmap1, | |
345 | const unsigned long *bitmap2, unsigned int bits) | |
346 | { | |
347 | return BITMAP_WEIGHT(bitmap1[idx] & bitmap2[idx], bits); | |
348 | } | |
349 | EXPORT_SYMBOL(__bitmap_weight_and); | |
350 | ||
351 | unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1, | |
352 | const unsigned long *bitmap2, unsigned int bits) | |
353 | { | |
354 | return BITMAP_WEIGHT(bitmap1[idx] & ~bitmap2[idx], bits); | |
355 | } | |
356 | EXPORT_SYMBOL(__bitmap_weight_andnot); | |
357 | ||
358 | void __bitmap_set(unsigned long *map, unsigned int start, int len) | |
359 | { | |
360 | unsigned long *p = map + BIT_WORD(start); | |
361 | const unsigned int size = start + len; | |
362 | int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); | |
363 | unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); | |
364 | ||
365 | while (len - bits_to_set >= 0) { | |
366 | *p |= mask_to_set; | |
367 | len -= bits_to_set; | |
368 | bits_to_set = BITS_PER_LONG; | |
369 | mask_to_set = ~0UL; | |
370 | p++; | |
371 | } | |
372 | if (len) { | |
373 | mask_to_set &= BITMAP_LAST_WORD_MASK(size); | |
374 | *p |= mask_to_set; | |
375 | } | |
376 | } | |
377 | EXPORT_SYMBOL(__bitmap_set); | |
378 | ||
379 | void __bitmap_clear(unsigned long *map, unsigned int start, int len) | |
380 | { | |
381 | unsigned long *p = map + BIT_WORD(start); | |
382 | const unsigned int size = start + len; | |
383 | int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); | |
384 | unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); | |
385 | ||
386 | while (len - bits_to_clear >= 0) { | |
387 | *p &= ~mask_to_clear; | |
388 | len -= bits_to_clear; | |
389 | bits_to_clear = BITS_PER_LONG; | |
390 | mask_to_clear = ~0UL; | |
391 | p++; | |
392 | } | |
393 | if (len) { | |
394 | mask_to_clear &= BITMAP_LAST_WORD_MASK(size); | |
395 | *p &= ~mask_to_clear; | |
396 | } | |
397 | } | |
398 | EXPORT_SYMBOL(__bitmap_clear); | |
399 | ||
400 | /** | |
401 | * bitmap_find_next_zero_area_off - find a contiguous aligned zero area | |
402 | * @map: The address to base the search on | |
403 | * @size: The bitmap size in bits | |
404 | * @start: The bitnumber to start searching at | |
405 | * @nr: The number of zeroed bits we're looking for | |
406 | * @align_mask: Alignment mask for zero area | |
407 | * @align_offset: Alignment offset for zero area. | |
408 | * | |
409 | * The @align_mask should be one less than a power of 2; the effect is that | |
410 | * the bit offset of all zero areas this function finds plus @align_offset | |
411 | * is multiple of that power of 2. | |
412 | */ | |
413 | unsigned long bitmap_find_next_zero_area_off(unsigned long *map, | |
414 | unsigned long size, | |
415 | unsigned long start, | |
416 | unsigned int nr, | |
417 | unsigned long align_mask, | |
418 | unsigned long align_offset) | |
419 | { | |
420 | unsigned long index, end, i; | |
421 | again: | |
422 | index = find_next_zero_bit(map, size, start); | |
423 | ||
424 | /* Align allocation */ | |
425 | index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset; | |
426 | ||
427 | end = index + nr; | |
428 | if (end > size) | |
429 | return end; | |
430 | i = find_next_bit(map, end, index); | |
431 | if (i < end) { | |
432 | start = i + 1; | |
433 | goto again; | |
434 | } | |
435 | return index; | |
436 | } | |
437 | EXPORT_SYMBOL(bitmap_find_next_zero_area_off); | |
438 | ||
439 | /** | |
440 | * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap | |
441 | * @buf: pointer to a bitmap | |
442 | * @pos: a bit position in @buf (0 <= @pos < @nbits) | |
443 | * @nbits: number of valid bit positions in @buf | |
444 | * | |
445 | * Map the bit at position @pos in @buf (of length @nbits) to the | |
446 | * ordinal of which set bit it is. If it is not set or if @pos | |
447 | * is not a valid bit position, map to -1. | |
448 | * | |
449 | * If for example, just bits 4 through 7 are set in @buf, then @pos | |
450 | * values 4 through 7 will get mapped to 0 through 3, respectively, | |
451 | * and other @pos values will get mapped to -1. When @pos value 7 | |
452 | * gets mapped to (returns) @ord value 3 in this example, that means | |
453 | * that bit 7 is the 3rd (starting with 0th) set bit in @buf. | |
454 | * | |
455 | * The bit positions 0 through @bits are valid positions in @buf. | |
456 | */ | |
457 | static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits) | |
458 | { | |
459 | if (pos >= nbits || !test_bit(pos, buf)) | |
460 | return -1; | |
461 | ||
462 | return bitmap_weight(buf, pos); | |
463 | } | |
464 | ||
465 | /** | |
466 | * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap | |
467 | * @dst: remapped result | |
468 | * @src: subset to be remapped | |
469 | * @old: defines domain of map | |
470 | * @new: defines range of map | |
471 | * @nbits: number of bits in each of these bitmaps | |
472 | * | |
473 | * Let @old and @new define a mapping of bit positions, such that | |
474 | * whatever position is held by the n-th set bit in @old is mapped | |
475 | * to the n-th set bit in @new. In the more general case, allowing | |
476 | * for the possibility that the weight 'w' of @new is less than the | |
477 | * weight of @old, map the position of the n-th set bit in @old to | |
478 | * the position of the m-th set bit in @new, where m == n % w. | |
479 | * | |
480 | * If either of the @old and @new bitmaps are empty, or if @src and | |
481 | * @dst point to the same location, then this routine copies @src | |
482 | * to @dst. | |
483 | * | |
484 | * The positions of unset bits in @old are mapped to themselves | |
485 | * (the identity map). | |
486 | * | |
487 | * Apply the above specified mapping to @src, placing the result in | |
488 | * @dst, clearing any bits previously set in @dst. | |
489 | * | |
490 | * For example, lets say that @old has bits 4 through 7 set, and | |
491 | * @new has bits 12 through 15 set. This defines the mapping of bit | |
492 | * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other | |
493 | * bit positions unchanged. So if say @src comes into this routine | |
494 | * with bits 1, 5 and 7 set, then @dst should leave with bits 1, | |
495 | * 13 and 15 set. | |
496 | */ | |
497 | void bitmap_remap(unsigned long *dst, const unsigned long *src, | |
498 | const unsigned long *old, const unsigned long *new, | |
499 | unsigned int nbits) | |
500 | { | |
501 | unsigned int oldbit, w; | |
502 | ||
503 | if (dst == src) /* following doesn't handle inplace remaps */ | |
504 | return; | |
505 | bitmap_zero(dst, nbits); | |
506 | ||
507 | w = bitmap_weight(new, nbits); | |
508 | for_each_set_bit(oldbit, src, nbits) { | |
509 | int n = bitmap_pos_to_ord(old, oldbit, nbits); | |
510 | ||
511 | if (n < 0 || w == 0) | |
512 | set_bit(oldbit, dst); /* identity map */ | |
513 | else | |
514 | set_bit(find_nth_bit(new, nbits, n % w), dst); | |
515 | } | |
516 | } | |
517 | EXPORT_SYMBOL(bitmap_remap); | |
518 | ||
519 | /** | |
520 | * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit | |
521 | * @oldbit: bit position to be mapped | |
522 | * @old: defines domain of map | |
523 | * @new: defines range of map | |
524 | * @bits: number of bits in each of these bitmaps | |
525 | * | |
526 | * Let @old and @new define a mapping of bit positions, such that | |
527 | * whatever position is held by the n-th set bit in @old is mapped | |
528 | * to the n-th set bit in @new. In the more general case, allowing | |
529 | * for the possibility that the weight 'w' of @new is less than the | |
530 | * weight of @old, map the position of the n-th set bit in @old to | |
531 | * the position of the m-th set bit in @new, where m == n % w. | |
532 | * | |
533 | * The positions of unset bits in @old are mapped to themselves | |
534 | * (the identity map). | |
535 | * | |
536 | * Apply the above specified mapping to bit position @oldbit, returning | |
537 | * the new bit position. | |
538 | * | |
539 | * For example, lets say that @old has bits 4 through 7 set, and | |
540 | * @new has bits 12 through 15 set. This defines the mapping of bit | |
541 | * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other | |
542 | * bit positions unchanged. So if say @oldbit is 5, then this routine | |
543 | * returns 13. | |
544 | */ | |
545 | int bitmap_bitremap(int oldbit, const unsigned long *old, | |
546 | const unsigned long *new, int bits) | |
547 | { | |
548 | int w = bitmap_weight(new, bits); | |
549 | int n = bitmap_pos_to_ord(old, oldbit, bits); | |
550 | if (n < 0 || w == 0) | |
551 | return oldbit; | |
552 | else | |
553 | return find_nth_bit(new, bits, n % w); | |
554 | } | |
555 | EXPORT_SYMBOL(bitmap_bitremap); | |
556 | ||
557 | #ifdef CONFIG_NUMA | |
558 | /** | |
559 | * bitmap_onto - translate one bitmap relative to another | |
560 | * @dst: resulting translated bitmap | |
561 | * @orig: original untranslated bitmap | |
562 | * @relmap: bitmap relative to which translated | |
563 | * @bits: number of bits in each of these bitmaps | |
564 | * | |
565 | * Set the n-th bit of @dst iff there exists some m such that the | |
566 | * n-th bit of @relmap is set, the m-th bit of @orig is set, and | |
567 | * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. | |
568 | * (If you understood the previous sentence the first time your | |
569 | * read it, you're overqualified for your current job.) | |
570 | * | |
571 | * In other words, @orig is mapped onto (surjectively) @dst, | |
572 | * using the map { <n, m> | the n-th bit of @relmap is the | |
573 | * m-th set bit of @relmap }. | |
574 | * | |
575 | * Any set bits in @orig above bit number W, where W is the | |
576 | * weight of (number of set bits in) @relmap are mapped nowhere. | |
577 | * In particular, if for all bits m set in @orig, m >= W, then | |
578 | * @dst will end up empty. In situations where the possibility | |
579 | * of such an empty result is not desired, one way to avoid it is | |
580 | * to use the bitmap_fold() operator, below, to first fold the | |
581 | * @orig bitmap over itself so that all its set bits x are in the | |
582 | * range 0 <= x < W. The bitmap_fold() operator does this by | |
583 | * setting the bit (m % W) in @dst, for each bit (m) set in @orig. | |
584 | * | |
585 | * Example [1] for bitmap_onto(): | |
586 | * Let's say @relmap has bits 30-39 set, and @orig has bits | |
587 | * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, | |
588 | * @dst will have bits 31, 33, 35, 37 and 39 set. | |
589 | * | |
590 | * When bit 0 is set in @orig, it means turn on the bit in | |
591 | * @dst corresponding to whatever is the first bit (if any) | |
592 | * that is turned on in @relmap. Since bit 0 was off in the | |
593 | * above example, we leave off that bit (bit 30) in @dst. | |
594 | * | |
595 | * When bit 1 is set in @orig (as in the above example), it | |
596 | * means turn on the bit in @dst corresponding to whatever | |
597 | * is the second bit that is turned on in @relmap. The second | |
598 | * bit in @relmap that was turned on in the above example was | |
599 | * bit 31, so we turned on bit 31 in @dst. | |
600 | * | |
601 | * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, | |
602 | * because they were the 4th, 6th, 8th and 10th set bits | |
603 | * set in @relmap, and the 4th, 6th, 8th and 10th bits of | |
604 | * @orig (i.e. bits 3, 5, 7 and 9) were also set. | |
605 | * | |
606 | * When bit 11 is set in @orig, it means turn on the bit in | |
607 | * @dst corresponding to whatever is the twelfth bit that is | |
608 | * turned on in @relmap. In the above example, there were | |
609 | * only ten bits turned on in @relmap (30..39), so that bit | |
610 | * 11 was set in @orig had no affect on @dst. | |
611 | * | |
612 | * Example [2] for bitmap_fold() + bitmap_onto(): | |
613 | * Let's say @relmap has these ten bits set:: | |
614 | * | |
615 | * 40 41 42 43 45 48 53 61 74 95 | |
616 | * | |
617 | * (for the curious, that's 40 plus the first ten terms of the | |
618 | * Fibonacci sequence.) | |
619 | * | |
620 | * Further lets say we use the following code, invoking | |
621 | * bitmap_fold() then bitmap_onto, as suggested above to | |
622 | * avoid the possibility of an empty @dst result:: | |
623 | * | |
624 | * unsigned long *tmp; // a temporary bitmap's bits | |
625 | * | |
626 | * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); | |
627 | * bitmap_onto(dst, tmp, relmap, bits); | |
628 | * | |
629 | * Then this table shows what various values of @dst would be, for | |
630 | * various @orig's. I list the zero-based positions of each set bit. | |
631 | * The tmp column shows the intermediate result, as computed by | |
632 | * using bitmap_fold() to fold the @orig bitmap modulo ten | |
633 | * (the weight of @relmap): | |
634 | * | |
635 | * =============== ============== ================= | |
636 | * @orig tmp @dst | |
637 | * 0 0 40 | |
638 | * 1 1 41 | |
639 | * 9 9 95 | |
640 | * 10 0 40 [#f1]_ | |
641 | * 1 3 5 7 1 3 5 7 41 43 48 61 | |
642 | * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 | |
643 | * 0 9 18 27 0 9 8 7 40 61 74 95 | |
644 | * 0 10 20 30 0 40 | |
645 | * 0 11 22 33 0 1 2 3 40 41 42 43 | |
646 | * 0 12 24 36 0 2 4 6 40 42 45 53 | |
647 | * 78 102 211 1 2 8 41 42 74 [#f1]_ | |
648 | * =============== ============== ================= | |
649 | * | |
650 | * .. [#f1] | |
651 | * | |
652 | * For these marked lines, if we hadn't first done bitmap_fold() | |
653 | * into tmp, then the @dst result would have been empty. | |
654 | * | |
655 | * If either of @orig or @relmap is empty (no set bits), then @dst | |
656 | * will be returned empty. | |
657 | * | |
658 | * If (as explained above) the only set bits in @orig are in positions | |
659 | * m where m >= W, (where W is the weight of @relmap) then @dst will | |
660 | * once again be returned empty. | |
661 | * | |
662 | * All bits in @dst not set by the above rule are cleared. | |
663 | */ | |
664 | void bitmap_onto(unsigned long *dst, const unsigned long *orig, | |
665 | const unsigned long *relmap, unsigned int bits) | |
666 | { | |
667 | unsigned int n, m; /* same meaning as in above comment */ | |
668 | ||
669 | if (dst == orig) /* following doesn't handle inplace mappings */ | |
670 | return; | |
671 | bitmap_zero(dst, bits); | |
672 | ||
673 | /* | |
674 | * The following code is a more efficient, but less | |
675 | * obvious, equivalent to the loop: | |
676 | * for (m = 0; m < bitmap_weight(relmap, bits); m++) { | |
677 | * n = find_nth_bit(orig, bits, m); | |
678 | * if (test_bit(m, orig)) | |
679 | * set_bit(n, dst); | |
680 | * } | |
681 | */ | |
682 | ||
683 | m = 0; | |
684 | for_each_set_bit(n, relmap, bits) { | |
685 | /* m == bitmap_pos_to_ord(relmap, n, bits) */ | |
686 | if (test_bit(m, orig)) | |
687 | set_bit(n, dst); | |
688 | m++; | |
689 | } | |
690 | } | |
691 | ||
692 | /** | |
693 | * bitmap_fold - fold larger bitmap into smaller, modulo specified size | |
694 | * @dst: resulting smaller bitmap | |
695 | * @orig: original larger bitmap | |
696 | * @sz: specified size | |
697 | * @nbits: number of bits in each of these bitmaps | |
698 | * | |
699 | * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. | |
700 | * Clear all other bits in @dst. See further the comment and | |
701 | * Example [2] for bitmap_onto() for why and how to use this. | |
702 | */ | |
703 | void bitmap_fold(unsigned long *dst, const unsigned long *orig, | |
704 | unsigned int sz, unsigned int nbits) | |
705 | { | |
706 | unsigned int oldbit; | |
707 | ||
708 | if (dst == orig) /* following doesn't handle inplace mappings */ | |
709 | return; | |
710 | bitmap_zero(dst, nbits); | |
711 | ||
712 | for_each_set_bit(oldbit, orig, nbits) | |
713 | set_bit(oldbit % sz, dst); | |
714 | } | |
715 | #endif /* CONFIG_NUMA */ | |
716 | ||
717 | unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags) | |
718 | { | |
719 | return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long), | |
720 | flags); | |
721 | } | |
722 | EXPORT_SYMBOL(bitmap_alloc); | |
723 | ||
724 | unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags) | |
725 | { | |
726 | return bitmap_alloc(nbits, flags | __GFP_ZERO); | |
727 | } | |
728 | EXPORT_SYMBOL(bitmap_zalloc); | |
729 | ||
730 | unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node) | |
731 | { | |
732 | return kmalloc_array_node(BITS_TO_LONGS(nbits), sizeof(unsigned long), | |
733 | flags, node); | |
734 | } | |
735 | EXPORT_SYMBOL(bitmap_alloc_node); | |
736 | ||
737 | unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node) | |
738 | { | |
739 | return bitmap_alloc_node(nbits, flags | __GFP_ZERO, node); | |
740 | } | |
741 | EXPORT_SYMBOL(bitmap_zalloc_node); | |
742 | ||
743 | void bitmap_free(const unsigned long *bitmap) | |
744 | { | |
745 | kfree(bitmap); | |
746 | } | |
747 | EXPORT_SYMBOL(bitmap_free); | |
748 | ||
749 | static void devm_bitmap_free(void *data) | |
750 | { | |
751 | unsigned long *bitmap = data; | |
752 | ||
753 | bitmap_free(bitmap); | |
754 | } | |
755 | ||
756 | unsigned long *devm_bitmap_alloc(struct device *dev, | |
757 | unsigned int nbits, gfp_t flags) | |
758 | { | |
759 | unsigned long *bitmap; | |
760 | int ret; | |
761 | ||
762 | bitmap = bitmap_alloc(nbits, flags); | |
763 | if (!bitmap) | |
764 | return NULL; | |
765 | ||
766 | ret = devm_add_action_or_reset(dev, devm_bitmap_free, bitmap); | |
767 | if (ret) | |
768 | return NULL; | |
769 | ||
770 | return bitmap; | |
771 | } | |
772 | EXPORT_SYMBOL_GPL(devm_bitmap_alloc); | |
773 | ||
774 | unsigned long *devm_bitmap_zalloc(struct device *dev, | |
775 | unsigned int nbits, gfp_t flags) | |
776 | { | |
777 | return devm_bitmap_alloc(dev, nbits, flags | __GFP_ZERO); | |
778 | } | |
779 | EXPORT_SYMBOL_GPL(devm_bitmap_zalloc); | |
780 | ||
781 | #if BITS_PER_LONG == 64 | |
782 | /** | |
783 | * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap | |
784 | * @bitmap: array of unsigned longs, the destination bitmap | |
785 | * @buf: array of u32 (in host byte order), the source bitmap | |
786 | * @nbits: number of bits in @bitmap | |
787 | */ | |
788 | void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits) | |
789 | { | |
790 | unsigned int i, halfwords; | |
791 | ||
792 | halfwords = DIV_ROUND_UP(nbits, 32); | |
793 | for (i = 0; i < halfwords; i++) { | |
794 | bitmap[i/2] = (unsigned long) buf[i]; | |
795 | if (++i < halfwords) | |
796 | bitmap[i/2] |= ((unsigned long) buf[i]) << 32; | |
797 | } | |
798 | ||
799 | /* Clear tail bits in last word beyond nbits. */ | |
800 | if (nbits % BITS_PER_LONG) | |
801 | bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits); | |
802 | } | |
803 | EXPORT_SYMBOL(bitmap_from_arr32); | |
804 | ||
805 | /** | |
806 | * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits | |
807 | * @buf: array of u32 (in host byte order), the dest bitmap | |
808 | * @bitmap: array of unsigned longs, the source bitmap | |
809 | * @nbits: number of bits in @bitmap | |
810 | */ | |
811 | void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits) | |
812 | { | |
813 | unsigned int i, halfwords; | |
814 | ||
815 | halfwords = DIV_ROUND_UP(nbits, 32); | |
816 | for (i = 0; i < halfwords; i++) { | |
817 | buf[i] = (u32) (bitmap[i/2] & UINT_MAX); | |
818 | if (++i < halfwords) | |
819 | buf[i] = (u32) (bitmap[i/2] >> 32); | |
820 | } | |
821 | ||
822 | /* Clear tail bits in last element of array beyond nbits. */ | |
823 | if (nbits % BITS_PER_LONG) | |
824 | buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31)); | |
825 | } | |
826 | EXPORT_SYMBOL(bitmap_to_arr32); | |
827 | #endif | |
828 | ||
829 | #if BITS_PER_LONG == 32 | |
830 | /** | |
831 | * bitmap_from_arr64 - copy the contents of u64 array of bits to bitmap | |
832 | * @bitmap: array of unsigned longs, the destination bitmap | |
833 | * @buf: array of u64 (in host byte order), the source bitmap | |
834 | * @nbits: number of bits in @bitmap | |
835 | */ | |
836 | void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits) | |
837 | { | |
838 | int n; | |
839 | ||
840 | for (n = nbits; n > 0; n -= 64) { | |
841 | u64 val = *buf++; | |
842 | ||
843 | *bitmap++ = val; | |
844 | if (n > 32) | |
845 | *bitmap++ = val >> 32; | |
846 | } | |
847 | ||
848 | /* | |
849 | * Clear tail bits in the last word beyond nbits. | |
850 | * | |
851 | * Negative index is OK because here we point to the word next | |
852 | * to the last word of the bitmap, except for nbits == 0, which | |
853 | * is tested implicitly. | |
854 | */ | |
855 | if (nbits % BITS_PER_LONG) | |
856 | bitmap[-1] &= BITMAP_LAST_WORD_MASK(nbits); | |
857 | } | |
858 | EXPORT_SYMBOL(bitmap_from_arr64); | |
859 | ||
860 | /** | |
861 | * bitmap_to_arr64 - copy the contents of bitmap to a u64 array of bits | |
862 | * @buf: array of u64 (in host byte order), the dest bitmap | |
863 | * @bitmap: array of unsigned longs, the source bitmap | |
864 | * @nbits: number of bits in @bitmap | |
865 | */ | |
866 | void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits) | |
867 | { | |
868 | const unsigned long *end = bitmap + BITS_TO_LONGS(nbits); | |
869 | ||
870 | while (bitmap < end) { | |
871 | *buf = *bitmap++; | |
872 | if (bitmap < end) | |
873 | *buf |= (u64)(*bitmap++) << 32; | |
874 | buf++; | |
875 | } | |
876 | ||
877 | /* Clear tail bits in the last element of array beyond nbits. */ | |
878 | if (nbits % 64) | |
879 | buf[-1] &= GENMASK_ULL((nbits - 1) % 64, 0); | |
880 | } | |
881 | EXPORT_SYMBOL(bitmap_to_arr64); | |
882 | #endif |