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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
37bool __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}
51EXPORT_SYMBOL(__bitmap_equal);
52
53bool __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
73void __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}
79EXPORT_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 */
92void __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}
122EXPORT_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
137void __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}
160EXPORT_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 */
199void 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}
227EXPORT_SYMBOL(bitmap_cut);
228
229bool __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}
243EXPORT_SYMBOL(__bitmap_and);
244
245void __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}
254EXPORT_SYMBOL(__bitmap_or);
255
256void __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}
265EXPORT_SYMBOL(__bitmap_xor);
266
267bool __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}
281EXPORT_SYMBOL(__bitmap_andnot);
282
283void __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}
293EXPORT_SYMBOL(__bitmap_replace);
294
295bool __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}
308EXPORT_SYMBOL(__bitmap_intersects);
309
310bool __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}
323EXPORT_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
338unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
339{
340 return BITMAP_WEIGHT(bitmap[idx], bits);
341}
342EXPORT_SYMBOL(__bitmap_weight);
343
344unsigned 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}
349EXPORT_SYMBOL(__bitmap_weight_and);
350
351void __bitmap_set(unsigned long *map, unsigned int start, int len)
352{
353 unsigned long *p = map + BIT_WORD(start);
354 const unsigned int size = start + len;
355 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
356 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
357
358 while (len - bits_to_set >= 0) {
359 *p |= mask_to_set;
360 len -= bits_to_set;
361 bits_to_set = BITS_PER_LONG;
362 mask_to_set = ~0UL;
363 p++;
364 }
365 if (len) {
366 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
367 *p |= mask_to_set;
368 }
369}
370EXPORT_SYMBOL(__bitmap_set);
371
372void __bitmap_clear(unsigned long *map, unsigned int start, int len)
373{
374 unsigned long *p = map + BIT_WORD(start);
375 const unsigned int size = start + len;
376 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
377 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
378
379 while (len - bits_to_clear >= 0) {
380 *p &= ~mask_to_clear;
381 len -= bits_to_clear;
382 bits_to_clear = BITS_PER_LONG;
383 mask_to_clear = ~0UL;
384 p++;
385 }
386 if (len) {
387 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
388 *p &= ~mask_to_clear;
389 }
390}
391EXPORT_SYMBOL(__bitmap_clear);
392
393/**
394 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
395 * @map: The address to base the search on
396 * @size: The bitmap size in bits
397 * @start: The bitnumber to start searching at
398 * @nr: The number of zeroed bits we're looking for
399 * @align_mask: Alignment mask for zero area
400 * @align_offset: Alignment offset for zero area.
401 *
402 * The @align_mask should be one less than a power of 2; the effect is that
403 * the bit offset of all zero areas this function finds plus @align_offset
404 * is multiple of that power of 2.
405 */
406unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
407 unsigned long size,
408 unsigned long start,
409 unsigned int nr,
410 unsigned long align_mask,
411 unsigned long align_offset)
412{
413 unsigned long index, end, i;
414again:
415 index = find_next_zero_bit(map, size, start);
416
417 /* Align allocation */
418 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
419
420 end = index + nr;
421 if (end > size)
422 return end;
423 i = find_next_bit(map, end, index);
424 if (i < end) {
425 start = i + 1;
426 goto again;
427 }
428 return index;
429}
430EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
431
432/**
433 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
434 * @buf: pointer to a bitmap
435 * @pos: a bit position in @buf (0 <= @pos < @nbits)
436 * @nbits: number of valid bit positions in @buf
437 *
438 * Map the bit at position @pos in @buf (of length @nbits) to the
439 * ordinal of which set bit it is. If it is not set or if @pos
440 * is not a valid bit position, map to -1.
441 *
442 * If for example, just bits 4 through 7 are set in @buf, then @pos
443 * values 4 through 7 will get mapped to 0 through 3, respectively,
444 * and other @pos values will get mapped to -1. When @pos value 7
445 * gets mapped to (returns) @ord value 3 in this example, that means
446 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
447 *
448 * The bit positions 0 through @bits are valid positions in @buf.
449 */
450static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
451{
452 if (pos >= nbits || !test_bit(pos, buf))
453 return -1;
454
455 return bitmap_weight(buf, pos);
456}
457
458/**
459 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
460 * @dst: remapped result
461 * @src: subset to be remapped
462 * @old: defines domain of map
463 * @new: defines range of map
464 * @nbits: number of bits in each of these bitmaps
465 *
466 * Let @old and @new define a mapping of bit positions, such that
467 * whatever position is held by the n-th set bit in @old is mapped
468 * to the n-th set bit in @new. In the more general case, allowing
469 * for the possibility that the weight 'w' of @new is less than the
470 * weight of @old, map the position of the n-th set bit in @old to
471 * the position of the m-th set bit in @new, where m == n % w.
472 *
473 * If either of the @old and @new bitmaps are empty, or if @src and
474 * @dst point to the same location, then this routine copies @src
475 * to @dst.
476 *
477 * The positions of unset bits in @old are mapped to themselves
478 * (the identity map).
479 *
480 * Apply the above specified mapping to @src, placing the result in
481 * @dst, clearing any bits previously set in @dst.
482 *
483 * For example, lets say that @old has bits 4 through 7 set, and
484 * @new has bits 12 through 15 set. This defines the mapping of bit
485 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
486 * bit positions unchanged. So if say @src comes into this routine
487 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
488 * 13 and 15 set.
489 */
490void bitmap_remap(unsigned long *dst, const unsigned long *src,
491 const unsigned long *old, const unsigned long *new,
492 unsigned int nbits)
493{
494 unsigned int oldbit, w;
495
496 if (dst == src) /* following doesn't handle inplace remaps */
497 return;
498 bitmap_zero(dst, nbits);
499
500 w = bitmap_weight(new, nbits);
501 for_each_set_bit(oldbit, src, nbits) {
502 int n = bitmap_pos_to_ord(old, oldbit, nbits);
503
504 if (n < 0 || w == 0)
505 set_bit(oldbit, dst); /* identity map */
506 else
507 set_bit(find_nth_bit(new, nbits, n % w), dst);
508 }
509}
510EXPORT_SYMBOL(bitmap_remap);
511
512/**
513 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
514 * @oldbit: bit position to be mapped
515 * @old: defines domain of map
516 * @new: defines range of map
517 * @bits: number of bits in each of these bitmaps
518 *
519 * Let @old and @new define a mapping of bit positions, such that
520 * whatever position is held by the n-th set bit in @old is mapped
521 * to the n-th set bit in @new. In the more general case, allowing
522 * for the possibility that the weight 'w' of @new is less than the
523 * weight of @old, map the position of the n-th set bit in @old to
524 * the position of the m-th set bit in @new, where m == n % w.
525 *
526 * The positions of unset bits in @old are mapped to themselves
527 * (the identity map).
528 *
529 * Apply the above specified mapping to bit position @oldbit, returning
530 * the new bit position.
531 *
532 * For example, lets say that @old has bits 4 through 7 set, and
533 * @new has bits 12 through 15 set. This defines the mapping of bit
534 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
535 * bit positions unchanged. So if say @oldbit is 5, then this routine
536 * returns 13.
537 */
538int bitmap_bitremap(int oldbit, const unsigned long *old,
539 const unsigned long *new, int bits)
540{
541 int w = bitmap_weight(new, bits);
542 int n = bitmap_pos_to_ord(old, oldbit, bits);
543 if (n < 0 || w == 0)
544 return oldbit;
545 else
546 return find_nth_bit(new, bits, n % w);
547}
548EXPORT_SYMBOL(bitmap_bitremap);
549
550#ifdef CONFIG_NUMA
551/**
552 * bitmap_onto - translate one bitmap relative to another
553 * @dst: resulting translated bitmap
554 * @orig: original untranslated bitmap
555 * @relmap: bitmap relative to which translated
556 * @bits: number of bits in each of these bitmaps
557 *
558 * Set the n-th bit of @dst iff there exists some m such that the
559 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
560 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
561 * (If you understood the previous sentence the first time your
562 * read it, you're overqualified for your current job.)
563 *
564 * In other words, @orig is mapped onto (surjectively) @dst,
565 * using the map { <n, m> | the n-th bit of @relmap is the
566 * m-th set bit of @relmap }.
567 *
568 * Any set bits in @orig above bit number W, where W is the
569 * weight of (number of set bits in) @relmap are mapped nowhere.
570 * In particular, if for all bits m set in @orig, m >= W, then
571 * @dst will end up empty. In situations where the possibility
572 * of such an empty result is not desired, one way to avoid it is
573 * to use the bitmap_fold() operator, below, to first fold the
574 * @orig bitmap over itself so that all its set bits x are in the
575 * range 0 <= x < W. The bitmap_fold() operator does this by
576 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
577 *
578 * Example [1] for bitmap_onto():
579 * Let's say @relmap has bits 30-39 set, and @orig has bits
580 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
581 * @dst will have bits 31, 33, 35, 37 and 39 set.
582 *
583 * When bit 0 is set in @orig, it means turn on the bit in
584 * @dst corresponding to whatever is the first bit (if any)
585 * that is turned on in @relmap. Since bit 0 was off in the
586 * above example, we leave off that bit (bit 30) in @dst.
587 *
588 * When bit 1 is set in @orig (as in the above example), it
589 * means turn on the bit in @dst corresponding to whatever
590 * is the second bit that is turned on in @relmap. The second
591 * bit in @relmap that was turned on in the above example was
592 * bit 31, so we turned on bit 31 in @dst.
593 *
594 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
595 * because they were the 4th, 6th, 8th and 10th set bits
596 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
597 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
598 *
599 * When bit 11 is set in @orig, it means turn on the bit in
600 * @dst corresponding to whatever is the twelfth bit that is
601 * turned on in @relmap. In the above example, there were
602 * only ten bits turned on in @relmap (30..39), so that bit
603 * 11 was set in @orig had no affect on @dst.
604 *
605 * Example [2] for bitmap_fold() + bitmap_onto():
606 * Let's say @relmap has these ten bits set::
607 *
608 * 40 41 42 43 45 48 53 61 74 95
609 *
610 * (for the curious, that's 40 plus the first ten terms of the
611 * Fibonacci sequence.)
612 *
613 * Further lets say we use the following code, invoking
614 * bitmap_fold() then bitmap_onto, as suggested above to
615 * avoid the possibility of an empty @dst result::
616 *
617 * unsigned long *tmp; // a temporary bitmap's bits
618 *
619 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
620 * bitmap_onto(dst, tmp, relmap, bits);
621 *
622 * Then this table shows what various values of @dst would be, for
623 * various @orig's. I list the zero-based positions of each set bit.
624 * The tmp column shows the intermediate result, as computed by
625 * using bitmap_fold() to fold the @orig bitmap modulo ten
626 * (the weight of @relmap):
627 *
628 * =============== ============== =================
629 * @orig tmp @dst
630 * 0 0 40
631 * 1 1 41
632 * 9 9 95
633 * 10 0 40 [#f1]_
634 * 1 3 5 7 1 3 5 7 41 43 48 61
635 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
636 * 0 9 18 27 0 9 8 7 40 61 74 95
637 * 0 10 20 30 0 40
638 * 0 11 22 33 0 1 2 3 40 41 42 43
639 * 0 12 24 36 0 2 4 6 40 42 45 53
640 * 78 102 211 1 2 8 41 42 74 [#f1]_
641 * =============== ============== =================
642 *
643 * .. [#f1]
644 *
645 * For these marked lines, if we hadn't first done bitmap_fold()
646 * into tmp, then the @dst result would have been empty.
647 *
648 * If either of @orig or @relmap is empty (no set bits), then @dst
649 * will be returned empty.
650 *
651 * If (as explained above) the only set bits in @orig are in positions
652 * m where m >= W, (where W is the weight of @relmap) then @dst will
653 * once again be returned empty.
654 *
655 * All bits in @dst not set by the above rule are cleared.
656 */
657void bitmap_onto(unsigned long *dst, const unsigned long *orig,
658 const unsigned long *relmap, unsigned int bits)
659{
660 unsigned int n, m; /* same meaning as in above comment */
661
662 if (dst == orig) /* following doesn't handle inplace mappings */
663 return;
664 bitmap_zero(dst, bits);
665
666 /*
667 * The following code is a more efficient, but less
668 * obvious, equivalent to the loop:
669 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
670 * n = find_nth_bit(orig, bits, m);
671 * if (test_bit(m, orig))
672 * set_bit(n, dst);
673 * }
674 */
675
676 m = 0;
677 for_each_set_bit(n, relmap, bits) {
678 /* m == bitmap_pos_to_ord(relmap, n, bits) */
679 if (test_bit(m, orig))
680 set_bit(n, dst);
681 m++;
682 }
683}
684
685/**
686 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
687 * @dst: resulting smaller bitmap
688 * @orig: original larger bitmap
689 * @sz: specified size
690 * @nbits: number of bits in each of these bitmaps
691 *
692 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
693 * Clear all other bits in @dst. See further the comment and
694 * Example [2] for bitmap_onto() for why and how to use this.
695 */
696void bitmap_fold(unsigned long *dst, const unsigned long *orig,
697 unsigned int sz, unsigned int nbits)
698{
699 unsigned int oldbit;
700
701 if (dst == orig) /* following doesn't handle inplace mappings */
702 return;
703 bitmap_zero(dst, nbits);
704
705 for_each_set_bit(oldbit, orig, nbits)
706 set_bit(oldbit % sz, dst);
707}
708#endif /* CONFIG_NUMA */
709
710unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
711{
712 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
713 flags);
714}
715EXPORT_SYMBOL(bitmap_alloc);
716
717unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
718{
719 return bitmap_alloc(nbits, flags | __GFP_ZERO);
720}
721EXPORT_SYMBOL(bitmap_zalloc);
722
723unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node)
724{
725 return kmalloc_array_node(BITS_TO_LONGS(nbits), sizeof(unsigned long),
726 flags, node);
727}
728EXPORT_SYMBOL(bitmap_alloc_node);
729
730unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node)
731{
732 return bitmap_alloc_node(nbits, flags | __GFP_ZERO, node);
733}
734EXPORT_SYMBOL(bitmap_zalloc_node);
735
736void bitmap_free(const unsigned long *bitmap)
737{
738 kfree(bitmap);
739}
740EXPORT_SYMBOL(bitmap_free);
741
742static void devm_bitmap_free(void *data)
743{
744 unsigned long *bitmap = data;
745
746 bitmap_free(bitmap);
747}
748
749unsigned long *devm_bitmap_alloc(struct device *dev,
750 unsigned int nbits, gfp_t flags)
751{
752 unsigned long *bitmap;
753 int ret;
754
755 bitmap = bitmap_alloc(nbits, flags);
756 if (!bitmap)
757 return NULL;
758
759 ret = devm_add_action_or_reset(dev, devm_bitmap_free, bitmap);
760 if (ret)
761 return NULL;
762
763 return bitmap;
764}
765EXPORT_SYMBOL_GPL(devm_bitmap_alloc);
766
767unsigned long *devm_bitmap_zalloc(struct device *dev,
768 unsigned int nbits, gfp_t flags)
769{
770 return devm_bitmap_alloc(dev, nbits, flags | __GFP_ZERO);
771}
772EXPORT_SYMBOL_GPL(devm_bitmap_zalloc);
773
774#if BITS_PER_LONG == 64
775/**
776 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
777 * @bitmap: array of unsigned longs, the destination bitmap
778 * @buf: array of u32 (in host byte order), the source bitmap
779 * @nbits: number of bits in @bitmap
780 */
781void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)
782{
783 unsigned int i, halfwords;
784
785 halfwords = DIV_ROUND_UP(nbits, 32);
786 for (i = 0; i < halfwords; i++) {
787 bitmap[i/2] = (unsigned long) buf[i];
788 if (++i < halfwords)
789 bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
790 }
791
792 /* Clear tail bits in last word beyond nbits. */
793 if (nbits % BITS_PER_LONG)
794 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
795}
796EXPORT_SYMBOL(bitmap_from_arr32);
797
798/**
799 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
800 * @buf: array of u32 (in host byte order), the dest bitmap
801 * @bitmap: array of unsigned longs, the source bitmap
802 * @nbits: number of bits in @bitmap
803 */
804void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
805{
806 unsigned int i, halfwords;
807
808 halfwords = DIV_ROUND_UP(nbits, 32);
809 for (i = 0; i < halfwords; i++) {
810 buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
811 if (++i < halfwords)
812 buf[i] = (u32) (bitmap[i/2] >> 32);
813 }
814
815 /* Clear tail bits in last element of array beyond nbits. */
816 if (nbits % BITS_PER_LONG)
817 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
818}
819EXPORT_SYMBOL(bitmap_to_arr32);
820#endif
821
822#if BITS_PER_LONG == 32
823/**
824 * bitmap_from_arr64 - copy the contents of u64 array of bits to bitmap
825 * @bitmap: array of unsigned longs, the destination bitmap
826 * @buf: array of u64 (in host byte order), the source bitmap
827 * @nbits: number of bits in @bitmap
828 */
829void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits)
830{
831 int n;
832
833 for (n = nbits; n > 0; n -= 64) {
834 u64 val = *buf++;
835
836 *bitmap++ = val;
837 if (n > 32)
838 *bitmap++ = val >> 32;
839 }
840
841 /*
842 * Clear tail bits in the last word beyond nbits.
843 *
844 * Negative index is OK because here we point to the word next
845 * to the last word of the bitmap, except for nbits == 0, which
846 * is tested implicitly.
847 */
848 if (nbits % BITS_PER_LONG)
849 bitmap[-1] &= BITMAP_LAST_WORD_MASK(nbits);
850}
851EXPORT_SYMBOL(bitmap_from_arr64);
852
853/**
854 * bitmap_to_arr64 - copy the contents of bitmap to a u64 array of bits
855 * @buf: array of u64 (in host byte order), the dest bitmap
856 * @bitmap: array of unsigned longs, the source bitmap
857 * @nbits: number of bits in @bitmap
858 */
859void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits)
860{
861 const unsigned long *end = bitmap + BITS_TO_LONGS(nbits);
862
863 while (bitmap < end) {
864 *buf = *bitmap++;
865 if (bitmap < end)
866 *buf |= (u64)(*bitmap++) << 32;
867 buf++;
868 }
869
870 /* Clear tail bits in the last element of array beyond nbits. */
871 if (nbits % 64)
872 buf[-1] &= GENMASK_ULL((nbits - 1) % 64, 0);
873}
874EXPORT_SYMBOL(bitmap_to_arr64);
875#endif
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/bug.h>
10#include <linux/ctype.h>
11#include <linux/device.h>
12#include <linux/errno.h>
13#include <linux/export.h>
14#include <linux/kernel.h>
15#include <linux/mm.h>
16#include <linux/slab.h>
17#include <linux/string.h>
18#include <linux/thread_info.h>
19#include <linux/uaccess.h>
20
21#include <asm/page.h>
22
23#include "kstrtox.h"
24
25/**
26 * DOC: bitmap introduction
27 *
28 * bitmaps provide an array of bits, implemented using an
29 * array of unsigned longs. The number of valid bits in a
30 * given bitmap does _not_ need to be an exact multiple of
31 * BITS_PER_LONG.
32 *
33 * The possible unused bits in the last, partially used word
34 * of a bitmap are 'don't care'. The implementation makes
35 * no particular effort to keep them zero. It ensures that
36 * their value will not affect the results of any operation.
37 * The bitmap operations that return Boolean (bitmap_empty,
38 * for example) or scalar (bitmap_weight, for example) results
39 * carefully filter out these unused bits from impacting their
40 * results.
41 *
42 * The byte ordering of bitmaps is more natural on little
43 * endian architectures. See the big-endian headers
44 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
45 * for the best explanations of this ordering.
46 */
47
48bool __bitmap_equal(const unsigned long *bitmap1,
49 const unsigned long *bitmap2, unsigned int bits)
50{
51 unsigned int k, lim = bits/BITS_PER_LONG;
52 for (k = 0; k < lim; ++k)
53 if (bitmap1[k] != bitmap2[k])
54 return false;
55
56 if (bits % BITS_PER_LONG)
57 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
58 return false;
59
60 return true;
61}
62EXPORT_SYMBOL(__bitmap_equal);
63
64bool __bitmap_or_equal(const unsigned long *bitmap1,
65 const unsigned long *bitmap2,
66 const unsigned long *bitmap3,
67 unsigned int bits)
68{
69 unsigned int k, lim = bits / BITS_PER_LONG;
70 unsigned long tmp;
71
72 for (k = 0; k < lim; ++k) {
73 if ((bitmap1[k] | bitmap2[k]) != bitmap3[k])
74 return false;
75 }
76
77 if (!(bits % BITS_PER_LONG))
78 return true;
79
80 tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k];
81 return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0;
82}
83
84void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
85{
86 unsigned int k, lim = BITS_TO_LONGS(bits);
87 for (k = 0; k < lim; ++k)
88 dst[k] = ~src[k];
89}
90EXPORT_SYMBOL(__bitmap_complement);
91
92/**
93 * __bitmap_shift_right - logical right shift of the bits in a bitmap
94 * @dst : destination bitmap
95 * @src : source bitmap
96 * @shift : shift by this many bits
97 * @nbits : bitmap size, in bits
98 *
99 * Shifting right (dividing) means moving bits in the MS -> LS bit
100 * direction. Zeros are fed into the vacated MS positions and the
101 * LS bits shifted off the bottom are lost.
102 */
103void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
104 unsigned shift, unsigned nbits)
105{
106 unsigned k, lim = BITS_TO_LONGS(nbits);
107 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
108 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
109 for (k = 0; off + k < lim; ++k) {
110 unsigned long upper, lower;
111
112 /*
113 * If shift is not word aligned, take lower rem bits of
114 * word above and make them the top rem bits of result.
115 */
116 if (!rem || off + k + 1 >= lim)
117 upper = 0;
118 else {
119 upper = src[off + k + 1];
120 if (off + k + 1 == lim - 1)
121 upper &= mask;
122 upper <<= (BITS_PER_LONG - rem);
123 }
124 lower = src[off + k];
125 if (off + k == lim - 1)
126 lower &= mask;
127 lower >>= rem;
128 dst[k] = lower | upper;
129 }
130 if (off)
131 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
132}
133EXPORT_SYMBOL(__bitmap_shift_right);
134
135
136/**
137 * __bitmap_shift_left - logical left shift of the bits in a bitmap
138 * @dst : destination bitmap
139 * @src : source bitmap
140 * @shift : shift by this many bits
141 * @nbits : bitmap size, in bits
142 *
143 * Shifting left (multiplying) means moving bits in the LS -> MS
144 * direction. Zeros are fed into the vacated LS bit positions
145 * and those MS bits shifted off the top are lost.
146 */
147
148void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
149 unsigned int shift, unsigned int nbits)
150{
151 int k;
152 unsigned int lim = BITS_TO_LONGS(nbits);
153 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
154 for (k = lim - off - 1; k >= 0; --k) {
155 unsigned long upper, lower;
156
157 /*
158 * If shift is not word aligned, take upper rem bits of
159 * word below and make them the bottom rem bits of result.
160 */
161 if (rem && k > 0)
162 lower = src[k - 1] >> (BITS_PER_LONG - rem);
163 else
164 lower = 0;
165 upper = src[k] << rem;
166 dst[k + off] = lower | upper;
167 }
168 if (off)
169 memset(dst, 0, off*sizeof(unsigned long));
170}
171EXPORT_SYMBOL(__bitmap_shift_left);
172
173/**
174 * bitmap_cut() - remove bit region from bitmap and right shift remaining bits
175 * @dst: destination bitmap, might overlap with src
176 * @src: source bitmap
177 * @first: start bit of region to be removed
178 * @cut: number of bits to remove
179 * @nbits: bitmap size, in bits
180 *
181 * Set the n-th bit of @dst iff the n-th bit of @src is set and
182 * n is less than @first, or the m-th bit of @src is set for any
183 * m such that @first <= n < nbits, and m = n + @cut.
184 *
185 * In pictures, example for a big-endian 32-bit architecture:
186 *
187 * The @src bitmap is::
188 *
189 * 31 63
190 * | |
191 * 10000000 11000001 11110010 00010101 10000000 11000001 01110010 00010101
192 * | | | |
193 * 16 14 0 32
194 *
195 * if @cut is 3, and @first is 14, bits 14-16 in @src are cut and @dst is::
196 *
197 * 31 63
198 * | |
199 * 10110000 00011000 00110010 00010101 00010000 00011000 00101110 01000010
200 * | | |
201 * 14 (bit 17 0 32
202 * from @src)
203 *
204 * Note that @dst and @src might overlap partially or entirely.
205 *
206 * This is implemented in the obvious way, with a shift and carry
207 * step for each moved bit. Optimisation is left as an exercise
208 * for the compiler.
209 */
210void bitmap_cut(unsigned long *dst, const unsigned long *src,
211 unsigned int first, unsigned int cut, unsigned int nbits)
212{
213 unsigned int len = BITS_TO_LONGS(nbits);
214 unsigned long keep = 0, carry;
215 int i;
216
217 if (first % BITS_PER_LONG) {
218 keep = src[first / BITS_PER_LONG] &
219 (~0UL >> (BITS_PER_LONG - first % BITS_PER_LONG));
220 }
221
222 memmove(dst, src, len * sizeof(*dst));
223
224 while (cut--) {
225 for (i = first / BITS_PER_LONG; i < len; i++) {
226 if (i < len - 1)
227 carry = dst[i + 1] & 1UL;
228 else
229 carry = 0;
230
231 dst[i] = (dst[i] >> 1) | (carry << (BITS_PER_LONG - 1));
232 }
233 }
234
235 dst[first / BITS_PER_LONG] &= ~0UL << (first % BITS_PER_LONG);
236 dst[first / BITS_PER_LONG] |= keep;
237}
238EXPORT_SYMBOL(bitmap_cut);
239
240bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
241 const unsigned long *bitmap2, unsigned int bits)
242{
243 unsigned int k;
244 unsigned int lim = bits/BITS_PER_LONG;
245 unsigned long result = 0;
246
247 for (k = 0; k < lim; k++)
248 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
249 if (bits % BITS_PER_LONG)
250 result |= (dst[k] = bitmap1[k] & bitmap2[k] &
251 BITMAP_LAST_WORD_MASK(bits));
252 return result != 0;
253}
254EXPORT_SYMBOL(__bitmap_and);
255
256void __bitmap_or(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}
265EXPORT_SYMBOL(__bitmap_or);
266
267void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
268 const unsigned long *bitmap2, unsigned int bits)
269{
270 unsigned int k;
271 unsigned int nr = BITS_TO_LONGS(bits);
272
273 for (k = 0; k < nr; k++)
274 dst[k] = bitmap1[k] ^ bitmap2[k];
275}
276EXPORT_SYMBOL(__bitmap_xor);
277
278bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
279 const unsigned long *bitmap2, unsigned int bits)
280{
281 unsigned int k;
282 unsigned int lim = bits/BITS_PER_LONG;
283 unsigned long result = 0;
284
285 for (k = 0; k < lim; k++)
286 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
287 if (bits % BITS_PER_LONG)
288 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
289 BITMAP_LAST_WORD_MASK(bits));
290 return result != 0;
291}
292EXPORT_SYMBOL(__bitmap_andnot);
293
294void __bitmap_replace(unsigned long *dst,
295 const unsigned long *old, const unsigned long *new,
296 const unsigned long *mask, unsigned int nbits)
297{
298 unsigned int k;
299 unsigned int nr = BITS_TO_LONGS(nbits);
300
301 for (k = 0; k < nr; k++)
302 dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]);
303}
304EXPORT_SYMBOL(__bitmap_replace);
305
306bool __bitmap_intersects(const unsigned long *bitmap1,
307 const unsigned long *bitmap2, unsigned int bits)
308{
309 unsigned int k, lim = bits/BITS_PER_LONG;
310 for (k = 0; k < lim; ++k)
311 if (bitmap1[k] & bitmap2[k])
312 return true;
313
314 if (bits % BITS_PER_LONG)
315 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
316 return true;
317 return false;
318}
319EXPORT_SYMBOL(__bitmap_intersects);
320
321bool __bitmap_subset(const unsigned long *bitmap1,
322 const unsigned long *bitmap2, unsigned int bits)
323{
324 unsigned int k, lim = bits/BITS_PER_LONG;
325 for (k = 0; k < lim; ++k)
326 if (bitmap1[k] & ~bitmap2[k])
327 return false;
328
329 if (bits % BITS_PER_LONG)
330 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
331 return false;
332 return true;
333}
334EXPORT_SYMBOL(__bitmap_subset);
335
336#define BITMAP_WEIGHT(FETCH, bits) \
337({ \
338 unsigned int __bits = (bits), idx, w = 0; \
339 \
340 for (idx = 0; idx < __bits / BITS_PER_LONG; idx++) \
341 w += hweight_long(FETCH); \
342 \
343 if (__bits % BITS_PER_LONG) \
344 w += hweight_long((FETCH) & BITMAP_LAST_WORD_MASK(__bits)); \
345 \
346 w; \
347})
348
349unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
350{
351 return BITMAP_WEIGHT(bitmap[idx], bits);
352}
353EXPORT_SYMBOL(__bitmap_weight);
354
355unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
356 const unsigned long *bitmap2, unsigned int bits)
357{
358 return BITMAP_WEIGHT(bitmap1[idx] & bitmap2[idx], bits);
359}
360EXPORT_SYMBOL(__bitmap_weight_and);
361
362void __bitmap_set(unsigned long *map, unsigned int start, int len)
363{
364 unsigned long *p = map + BIT_WORD(start);
365 const unsigned int size = start + len;
366 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
367 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
368
369 while (len - bits_to_set >= 0) {
370 *p |= mask_to_set;
371 len -= bits_to_set;
372 bits_to_set = BITS_PER_LONG;
373 mask_to_set = ~0UL;
374 p++;
375 }
376 if (len) {
377 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
378 *p |= mask_to_set;
379 }
380}
381EXPORT_SYMBOL(__bitmap_set);
382
383void __bitmap_clear(unsigned long *map, unsigned int start, int len)
384{
385 unsigned long *p = map + BIT_WORD(start);
386 const unsigned int size = start + len;
387 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
388 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
389
390 while (len - bits_to_clear >= 0) {
391 *p &= ~mask_to_clear;
392 len -= bits_to_clear;
393 bits_to_clear = BITS_PER_LONG;
394 mask_to_clear = ~0UL;
395 p++;
396 }
397 if (len) {
398 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
399 *p &= ~mask_to_clear;
400 }
401}
402EXPORT_SYMBOL(__bitmap_clear);
403
404/**
405 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
406 * @map: The address to base the search on
407 * @size: The bitmap size in bits
408 * @start: The bitnumber to start searching at
409 * @nr: The number of zeroed bits we're looking for
410 * @align_mask: Alignment mask for zero area
411 * @align_offset: Alignment offset for zero area.
412 *
413 * The @align_mask should be one less than a power of 2; the effect is that
414 * the bit offset of all zero areas this function finds plus @align_offset
415 * is multiple of that power of 2.
416 */
417unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
418 unsigned long size,
419 unsigned long start,
420 unsigned int nr,
421 unsigned long align_mask,
422 unsigned long align_offset)
423{
424 unsigned long index, end, i;
425again:
426 index = find_next_zero_bit(map, size, start);
427
428 /* Align allocation */
429 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
430
431 end = index + nr;
432 if (end > size)
433 return end;
434 i = find_next_bit(map, end, index);
435 if (i < end) {
436 start = i + 1;
437 goto again;
438 }
439 return index;
440}
441EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
442
443/*
444 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
445 * second version by Paul Jackson, third by Joe Korty.
446 */
447
448/**
449 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
450 *
451 * @ubuf: pointer to user buffer containing string.
452 * @ulen: buffer size in bytes. If string is smaller than this
453 * then it must be terminated with a \0.
454 * @maskp: pointer to bitmap array that will contain result.
455 * @nmaskbits: size of bitmap, in bits.
456 */
457int bitmap_parse_user(const char __user *ubuf,
458 unsigned int ulen, unsigned long *maskp,
459 int nmaskbits)
460{
461 char *buf;
462 int ret;
463
464 buf = memdup_user_nul(ubuf, ulen);
465 if (IS_ERR(buf))
466 return PTR_ERR(buf);
467
468 ret = bitmap_parse(buf, UINT_MAX, maskp, nmaskbits);
469
470 kfree(buf);
471 return ret;
472}
473EXPORT_SYMBOL(bitmap_parse_user);
474
475/**
476 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
477 * @list: indicates whether the bitmap must be list
478 * @buf: page aligned buffer into which string is placed
479 * @maskp: pointer to bitmap to convert
480 * @nmaskbits: size of bitmap, in bits
481 *
482 * Output format is a comma-separated list of decimal numbers and
483 * ranges if list is specified or hex digits grouped into comma-separated
484 * sets of 8 digits/set. Returns the number of characters written to buf.
485 *
486 * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
487 * area and that sufficient storage remains at @buf to accommodate the
488 * bitmap_print_to_pagebuf() output. Returns the number of characters
489 * actually printed to @buf, excluding terminating '\0'.
490 */
491int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
492 int nmaskbits)
493{
494 ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
495
496 return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
497 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
498}
499EXPORT_SYMBOL(bitmap_print_to_pagebuf);
500
501/**
502 * bitmap_print_to_buf - convert bitmap to list or hex format ASCII string
503 * @list: indicates whether the bitmap must be list
504 * true: print in decimal list format
505 * false: print in hexadecimal bitmask format
506 * @buf: buffer into which string is placed
507 * @maskp: pointer to bitmap to convert
508 * @nmaskbits: size of bitmap, in bits
509 * @off: in the string from which we are copying, We copy to @buf
510 * @count: the maximum number of bytes to print
511 */
512static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
513 int nmaskbits, loff_t off, size_t count)
514{
515 const char *fmt = list ? "%*pbl\n" : "%*pb\n";
516 ssize_t size;
517 void *data;
518
519 data = kasprintf(GFP_KERNEL, fmt, nmaskbits, maskp);
520 if (!data)
521 return -ENOMEM;
522
523 size = memory_read_from_buffer(buf, count, &off, data, strlen(data) + 1);
524 kfree(data);
525
526 return size;
527}
528
529/**
530 * bitmap_print_bitmask_to_buf - convert bitmap to hex bitmask format ASCII string
531 * @buf: buffer into which string is placed
532 * @maskp: pointer to bitmap to convert
533 * @nmaskbits: size of bitmap, in bits
534 * @off: in the string from which we are copying, We copy to @buf
535 * @count: the maximum number of bytes to print
536 *
537 * The bitmap_print_to_pagebuf() is used indirectly via its cpumap wrapper
538 * cpumap_print_to_pagebuf() or directly by drivers to export hexadecimal
539 * bitmask and decimal list to userspace by sysfs ABI.
540 * Drivers might be using a normal attribute for this kind of ABIs. A
541 * normal attribute typically has show entry as below::
542 *
543 * static ssize_t example_attribute_show(struct device *dev,
544 * struct device_attribute *attr, char *buf)
545 * {
546 * ...
547 * return bitmap_print_to_pagebuf(true, buf, &mask, nr_trig_max);
548 * }
549 *
550 * show entry of attribute has no offset and count parameters and this
551 * means the file is limited to one page only.
552 * bitmap_print_to_pagebuf() API works terribly well for this kind of
553 * normal attribute with buf parameter and without offset, count::
554 *
555 * bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
556 * int nmaskbits)
557 * {
558 * }
559 *
560 * The problem is once we have a large bitmap, we have a chance to get a
561 * bitmask or list more than one page. Especially for list, it could be
562 * as complex as 0,3,5,7,9,... We have no simple way to know it exact size.
563 * It turns out bin_attribute is a way to break this limit. bin_attribute
564 * has show entry as below::
565 *
566 * static ssize_t
567 * example_bin_attribute_show(struct file *filp, struct kobject *kobj,
568 * struct bin_attribute *attr, char *buf,
569 * loff_t offset, size_t count)
570 * {
571 * ...
572 * }
573 *
574 * With the new offset and count parameters, this makes sysfs ABI be able
575 * to support file size more than one page. For example, offset could be
576 * >= 4096.
577 * bitmap_print_bitmask_to_buf(), bitmap_print_list_to_buf() wit their
578 * cpumap wrapper cpumap_print_bitmask_to_buf(), cpumap_print_list_to_buf()
579 * make those drivers be able to support large bitmask and list after they
580 * move to use bin_attribute. In result, we have to pass the corresponding
581 * parameters such as off, count from bin_attribute show entry to this API.
582 *
583 * The role of cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf()
584 * is similar with cpumap_print_to_pagebuf(), the difference is that
585 * bitmap_print_to_pagebuf() mainly serves sysfs attribute with the assumption
586 * the destination buffer is exactly one page and won't be more than one page.
587 * cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf(), on the other
588 * hand, mainly serves bin_attribute which doesn't work with exact one page,
589 * and it can break the size limit of converted decimal list and hexadecimal
590 * bitmask.
591 *
592 * WARNING!
593 *
594 * This function is not a replacement for sprintf() or bitmap_print_to_pagebuf().
595 * It is intended to workaround sysfs limitations discussed above and should be
596 * used carefully in general case for the following reasons:
597 *
598 * - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf().
599 * - Memory complexity is O(nbits), comparing to O(1) for snprintf().
600 * - @off and @count are NOT offset and number of bits to print.
601 * - If printing part of bitmap as list, the resulting string is not a correct
602 * list representation of bitmap. Particularly, some bits within or out of
603 * related interval may be erroneously set or unset. The format of the string
604 * may be broken, so bitmap_parselist-like parser may fail parsing it.
605 * - If printing the whole bitmap as list by parts, user must ensure the order
606 * of calls of the function such that the offset is incremented linearly.
607 * - If printing the whole bitmap as list by parts, user must keep bitmap
608 * unchanged between the very first and very last call. Otherwise concatenated
609 * result may be incorrect, and format may be broken.
610 *
611 * Returns the number of characters actually printed to @buf
612 */
613int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
614 int nmaskbits, loff_t off, size_t count)
615{
616 return bitmap_print_to_buf(false, buf, maskp, nmaskbits, off, count);
617}
618EXPORT_SYMBOL(bitmap_print_bitmask_to_buf);
619
620/**
621 * bitmap_print_list_to_buf - convert bitmap to decimal list format ASCII string
622 * @buf: buffer into which string is placed
623 * @maskp: pointer to bitmap to convert
624 * @nmaskbits: size of bitmap, in bits
625 * @off: in the string from which we are copying, We copy to @buf
626 * @count: the maximum number of bytes to print
627 *
628 * Everything is same with the above bitmap_print_bitmask_to_buf() except
629 * the print format.
630 */
631int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
632 int nmaskbits, loff_t off, size_t count)
633{
634 return bitmap_print_to_buf(true, buf, maskp, nmaskbits, off, count);
635}
636EXPORT_SYMBOL(bitmap_print_list_to_buf);
637
638/*
639 * Region 9-38:4/10 describes the following bitmap structure:
640 * 0 9 12 18 38 N
641 * .........****......****......****..................
642 * ^ ^ ^ ^ ^
643 * start off group_len end nbits
644 */
645struct region {
646 unsigned int start;
647 unsigned int off;
648 unsigned int group_len;
649 unsigned int end;
650 unsigned int nbits;
651};
652
653static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
654{
655 unsigned int start;
656
657 for (start = r->start; start <= r->end; start += r->group_len)
658 bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
659}
660
661static int bitmap_check_region(const struct region *r)
662{
663 if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
664 return -EINVAL;
665
666 if (r->end >= r->nbits)
667 return -ERANGE;
668
669 return 0;
670}
671
672static const char *bitmap_getnum(const char *str, unsigned int *num,
673 unsigned int lastbit)
674{
675 unsigned long long n;
676 unsigned int len;
677
678 if (str[0] == 'N') {
679 *num = lastbit;
680 return str + 1;
681 }
682
683 len = _parse_integer(str, 10, &n);
684 if (!len)
685 return ERR_PTR(-EINVAL);
686 if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)
687 return ERR_PTR(-EOVERFLOW);
688
689 *num = n;
690 return str + len;
691}
692
693static inline bool end_of_str(char c)
694{
695 return c == '\0' || c == '\n';
696}
697
698static inline bool __end_of_region(char c)
699{
700 return isspace(c) || c == ',';
701}
702
703static inline bool end_of_region(char c)
704{
705 return __end_of_region(c) || end_of_str(c);
706}
707
708/*
709 * The format allows commas and whitespaces at the beginning
710 * of the region.
711 */
712static const char *bitmap_find_region(const char *str)
713{
714 while (__end_of_region(*str))
715 str++;
716
717 return end_of_str(*str) ? NULL : str;
718}
719
720static const char *bitmap_find_region_reverse(const char *start, const char *end)
721{
722 while (start <= end && __end_of_region(*end))
723 end--;
724
725 return end;
726}
727
728static const char *bitmap_parse_region(const char *str, struct region *r)
729{
730 unsigned int lastbit = r->nbits - 1;
731
732 if (!strncasecmp(str, "all", 3)) {
733 r->start = 0;
734 r->end = lastbit;
735 str += 3;
736
737 goto check_pattern;
738 }
739
740 str = bitmap_getnum(str, &r->start, lastbit);
741 if (IS_ERR(str))
742 return str;
743
744 if (end_of_region(*str))
745 goto no_end;
746
747 if (*str != '-')
748 return ERR_PTR(-EINVAL);
749
750 str = bitmap_getnum(str + 1, &r->end, lastbit);
751 if (IS_ERR(str))
752 return str;
753
754check_pattern:
755 if (end_of_region(*str))
756 goto no_pattern;
757
758 if (*str != ':')
759 return ERR_PTR(-EINVAL);
760
761 str = bitmap_getnum(str + 1, &r->off, lastbit);
762 if (IS_ERR(str))
763 return str;
764
765 if (*str != '/')
766 return ERR_PTR(-EINVAL);
767
768 return bitmap_getnum(str + 1, &r->group_len, lastbit);
769
770no_end:
771 r->end = r->start;
772no_pattern:
773 r->off = r->end + 1;
774 r->group_len = r->end + 1;
775
776 return end_of_str(*str) ? NULL : str;
777}
778
779/**
780 * bitmap_parselist - convert list format ASCII string to bitmap
781 * @buf: read user string from this buffer; must be terminated
782 * with a \0 or \n.
783 * @maskp: write resulting mask here
784 * @nmaskbits: number of bits in mask to be written
785 *
786 * Input format is a comma-separated list of decimal numbers and
787 * ranges. Consecutively set bits are shown as two hyphen-separated
788 * decimal numbers, the smallest and largest bit numbers set in
789 * the range.
790 * Optionally each range can be postfixed to denote that only parts of it
791 * should be set. The range will divided to groups of specific size.
792 * From each group will be used only defined amount of bits.
793 * Syntax: range:used_size/group_size
794 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
795 * The value 'N' can be used as a dynamically substituted token for the
796 * maximum allowed value; i.e (nmaskbits - 1). Keep in mind that it is
797 * dynamic, so if system changes cause the bitmap width to change, such
798 * as more cores in a CPU list, then any ranges using N will also change.
799 *
800 * Returns: 0 on success, -errno on invalid input strings. Error values:
801 *
802 * - ``-EINVAL``: wrong region format
803 * - ``-EINVAL``: invalid character in string
804 * - ``-ERANGE``: bit number specified too large for mask
805 * - ``-EOVERFLOW``: integer overflow in the input parameters
806 */
807int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
808{
809 struct region r;
810 long ret;
811
812 r.nbits = nmaskbits;
813 bitmap_zero(maskp, r.nbits);
814
815 while (buf) {
816 buf = bitmap_find_region(buf);
817 if (buf == NULL)
818 return 0;
819
820 buf = bitmap_parse_region(buf, &r);
821 if (IS_ERR(buf))
822 return PTR_ERR(buf);
823
824 ret = bitmap_check_region(&r);
825 if (ret)
826 return ret;
827
828 bitmap_set_region(&r, maskp);
829 }
830
831 return 0;
832}
833EXPORT_SYMBOL(bitmap_parselist);
834
835
836/**
837 * bitmap_parselist_user() - convert user buffer's list format ASCII
838 * string to bitmap
839 *
840 * @ubuf: pointer to user buffer containing string.
841 * @ulen: buffer size in bytes. If string is smaller than this
842 * then it must be terminated with a \0.
843 * @maskp: pointer to bitmap array that will contain result.
844 * @nmaskbits: size of bitmap, in bits.
845 *
846 * Wrapper for bitmap_parselist(), providing it with user buffer.
847 */
848int bitmap_parselist_user(const char __user *ubuf,
849 unsigned int ulen, unsigned long *maskp,
850 int nmaskbits)
851{
852 char *buf;
853 int ret;
854
855 buf = memdup_user_nul(ubuf, ulen);
856 if (IS_ERR(buf))
857 return PTR_ERR(buf);
858
859 ret = bitmap_parselist(buf, maskp, nmaskbits);
860
861 kfree(buf);
862 return ret;
863}
864EXPORT_SYMBOL(bitmap_parselist_user);
865
866static const char *bitmap_get_x32_reverse(const char *start,
867 const char *end, u32 *num)
868{
869 u32 ret = 0;
870 int c, i;
871
872 for (i = 0; i < 32; i += 4) {
873 c = hex_to_bin(*end--);
874 if (c < 0)
875 return ERR_PTR(-EINVAL);
876
877 ret |= c << i;
878
879 if (start > end || __end_of_region(*end))
880 goto out;
881 }
882
883 if (hex_to_bin(*end--) >= 0)
884 return ERR_PTR(-EOVERFLOW);
885out:
886 *num = ret;
887 return end;
888}
889
890/**
891 * bitmap_parse - convert an ASCII hex string into a bitmap.
892 * @start: pointer to buffer containing string.
893 * @buflen: buffer size in bytes. If string is smaller than this
894 * then it must be terminated with a \0 or \n. In that case,
895 * UINT_MAX may be provided instead of string length.
896 * @maskp: pointer to bitmap array that will contain result.
897 * @nmaskbits: size of bitmap, in bits.
898 *
899 * Commas group hex digits into chunks. Each chunk defines exactly 32
900 * bits of the resultant bitmask. No chunk may specify a value larger
901 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
902 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
903 * characters. Grouping such as "1,,5", ",44", "," or "" is allowed.
904 * Leading, embedded and trailing whitespace accepted.
905 */
906int bitmap_parse(const char *start, unsigned int buflen,
907 unsigned long *maskp, int nmaskbits)
908{
909 const char *end = strnchrnul(start, buflen, '\n') - 1;
910 int chunks = BITS_TO_U32(nmaskbits);
911 u32 *bitmap = (u32 *)maskp;
912 int unset_bit;
913 int chunk;
914
915 for (chunk = 0; ; chunk++) {
916 end = bitmap_find_region_reverse(start, end);
917 if (start > end)
918 break;
919
920 if (!chunks--)
921 return -EOVERFLOW;
922
923#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
924 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]);
925#else
926 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]);
927#endif
928 if (IS_ERR(end))
929 return PTR_ERR(end);
930 }
931
932 unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
933 if (unset_bit < nmaskbits) {
934 bitmap_clear(maskp, unset_bit, nmaskbits - unset_bit);
935 return 0;
936 }
937
938 if (find_next_bit(maskp, unset_bit, nmaskbits) != unset_bit)
939 return -EOVERFLOW;
940
941 return 0;
942}
943EXPORT_SYMBOL(bitmap_parse);
944
945/**
946 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
947 * @buf: pointer to a bitmap
948 * @pos: a bit position in @buf (0 <= @pos < @nbits)
949 * @nbits: number of valid bit positions in @buf
950 *
951 * Map the bit at position @pos in @buf (of length @nbits) to the
952 * ordinal of which set bit it is. If it is not set or if @pos
953 * is not a valid bit position, map to -1.
954 *
955 * If for example, just bits 4 through 7 are set in @buf, then @pos
956 * values 4 through 7 will get mapped to 0 through 3, respectively,
957 * and other @pos values will get mapped to -1. When @pos value 7
958 * gets mapped to (returns) @ord value 3 in this example, that means
959 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
960 *
961 * The bit positions 0 through @bits are valid positions in @buf.
962 */
963static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
964{
965 if (pos >= nbits || !test_bit(pos, buf))
966 return -1;
967
968 return bitmap_weight(buf, pos);
969}
970
971/**
972 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
973 * @dst: remapped result
974 * @src: subset to be remapped
975 * @old: defines domain of map
976 * @new: defines range of map
977 * @nbits: number of bits in each of these bitmaps
978 *
979 * Let @old and @new define a mapping of bit positions, such that
980 * whatever position is held by the n-th set bit in @old is mapped
981 * to the n-th set bit in @new. In the more general case, allowing
982 * for the possibility that the weight 'w' of @new is less than the
983 * weight of @old, map the position of the n-th set bit in @old to
984 * the position of the m-th set bit in @new, where m == n % w.
985 *
986 * If either of the @old and @new bitmaps are empty, or if @src and
987 * @dst point to the same location, then this routine copies @src
988 * to @dst.
989 *
990 * The positions of unset bits in @old are mapped to themselves
991 * (the identify map).
992 *
993 * Apply the above specified mapping to @src, placing the result in
994 * @dst, clearing any bits previously set in @dst.
995 *
996 * For example, lets say that @old has bits 4 through 7 set, and
997 * @new has bits 12 through 15 set. This defines the mapping of bit
998 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
999 * bit positions unchanged. So if say @src comes into this routine
1000 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
1001 * 13 and 15 set.
1002 */
1003void bitmap_remap(unsigned long *dst, const unsigned long *src,
1004 const unsigned long *old, const unsigned long *new,
1005 unsigned int nbits)
1006{
1007 unsigned int oldbit, w;
1008
1009 if (dst == src) /* following doesn't handle inplace remaps */
1010 return;
1011 bitmap_zero(dst, nbits);
1012
1013 w = bitmap_weight(new, nbits);
1014 for_each_set_bit(oldbit, src, nbits) {
1015 int n = bitmap_pos_to_ord(old, oldbit, nbits);
1016
1017 if (n < 0 || w == 0)
1018 set_bit(oldbit, dst); /* identity map */
1019 else
1020 set_bit(find_nth_bit(new, nbits, n % w), dst);
1021 }
1022}
1023EXPORT_SYMBOL(bitmap_remap);
1024
1025/**
1026 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
1027 * @oldbit: bit position to be mapped
1028 * @old: defines domain of map
1029 * @new: defines range of map
1030 * @bits: number of bits in each of these bitmaps
1031 *
1032 * Let @old and @new define a mapping of bit positions, such that
1033 * whatever position is held by the n-th set bit in @old is mapped
1034 * to the n-th set bit in @new. In the more general case, allowing
1035 * for the possibility that the weight 'w' of @new is less than the
1036 * weight of @old, map the position of the n-th set bit in @old to
1037 * the position of the m-th set bit in @new, where m == n % w.
1038 *
1039 * The positions of unset bits in @old are mapped to themselves
1040 * (the identify map).
1041 *
1042 * Apply the above specified mapping to bit position @oldbit, returning
1043 * the new bit position.
1044 *
1045 * For example, lets say that @old has bits 4 through 7 set, and
1046 * @new has bits 12 through 15 set. This defines the mapping of bit
1047 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
1048 * bit positions unchanged. So if say @oldbit is 5, then this routine
1049 * returns 13.
1050 */
1051int bitmap_bitremap(int oldbit, const unsigned long *old,
1052 const unsigned long *new, int bits)
1053{
1054 int w = bitmap_weight(new, bits);
1055 int n = bitmap_pos_to_ord(old, oldbit, bits);
1056 if (n < 0 || w == 0)
1057 return oldbit;
1058 else
1059 return find_nth_bit(new, bits, n % w);
1060}
1061EXPORT_SYMBOL(bitmap_bitremap);
1062
1063#ifdef CONFIG_NUMA
1064/**
1065 * bitmap_onto - translate one bitmap relative to another
1066 * @dst: resulting translated bitmap
1067 * @orig: original untranslated bitmap
1068 * @relmap: bitmap relative to which translated
1069 * @bits: number of bits in each of these bitmaps
1070 *
1071 * Set the n-th bit of @dst iff there exists some m such that the
1072 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
1073 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
1074 * (If you understood the previous sentence the first time your
1075 * read it, you're overqualified for your current job.)
1076 *
1077 * In other words, @orig is mapped onto (surjectively) @dst,
1078 * using the map { <n, m> | the n-th bit of @relmap is the
1079 * m-th set bit of @relmap }.
1080 *
1081 * Any set bits in @orig above bit number W, where W is the
1082 * weight of (number of set bits in) @relmap are mapped nowhere.
1083 * In particular, if for all bits m set in @orig, m >= W, then
1084 * @dst will end up empty. In situations where the possibility
1085 * of such an empty result is not desired, one way to avoid it is
1086 * to use the bitmap_fold() operator, below, to first fold the
1087 * @orig bitmap over itself so that all its set bits x are in the
1088 * range 0 <= x < W. The bitmap_fold() operator does this by
1089 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
1090 *
1091 * Example [1] for bitmap_onto():
1092 * Let's say @relmap has bits 30-39 set, and @orig has bits
1093 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
1094 * @dst will have bits 31, 33, 35, 37 and 39 set.
1095 *
1096 * When bit 0 is set in @orig, it means turn on the bit in
1097 * @dst corresponding to whatever is the first bit (if any)
1098 * that is turned on in @relmap. Since bit 0 was off in the
1099 * above example, we leave off that bit (bit 30) in @dst.
1100 *
1101 * When bit 1 is set in @orig (as in the above example), it
1102 * means turn on the bit in @dst corresponding to whatever
1103 * is the second bit that is turned on in @relmap. The second
1104 * bit in @relmap that was turned on in the above example was
1105 * bit 31, so we turned on bit 31 in @dst.
1106 *
1107 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
1108 * because they were the 4th, 6th, 8th and 10th set bits
1109 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
1110 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
1111 *
1112 * When bit 11 is set in @orig, it means turn on the bit in
1113 * @dst corresponding to whatever is the twelfth bit that is
1114 * turned on in @relmap. In the above example, there were
1115 * only ten bits turned on in @relmap (30..39), so that bit
1116 * 11 was set in @orig had no affect on @dst.
1117 *
1118 * Example [2] for bitmap_fold() + bitmap_onto():
1119 * Let's say @relmap has these ten bits set::
1120 *
1121 * 40 41 42 43 45 48 53 61 74 95
1122 *
1123 * (for the curious, that's 40 plus the first ten terms of the
1124 * Fibonacci sequence.)
1125 *
1126 * Further lets say we use the following code, invoking
1127 * bitmap_fold() then bitmap_onto, as suggested above to
1128 * avoid the possibility of an empty @dst result::
1129 *
1130 * unsigned long *tmp; // a temporary bitmap's bits
1131 *
1132 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
1133 * bitmap_onto(dst, tmp, relmap, bits);
1134 *
1135 * Then this table shows what various values of @dst would be, for
1136 * various @orig's. I list the zero-based positions of each set bit.
1137 * The tmp column shows the intermediate result, as computed by
1138 * using bitmap_fold() to fold the @orig bitmap modulo ten
1139 * (the weight of @relmap):
1140 *
1141 * =============== ============== =================
1142 * @orig tmp @dst
1143 * 0 0 40
1144 * 1 1 41
1145 * 9 9 95
1146 * 10 0 40 [#f1]_
1147 * 1 3 5 7 1 3 5 7 41 43 48 61
1148 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
1149 * 0 9 18 27 0 9 8 7 40 61 74 95
1150 * 0 10 20 30 0 40
1151 * 0 11 22 33 0 1 2 3 40 41 42 43
1152 * 0 12 24 36 0 2 4 6 40 42 45 53
1153 * 78 102 211 1 2 8 41 42 74 [#f1]_
1154 * =============== ============== =================
1155 *
1156 * .. [#f1]
1157 *
1158 * For these marked lines, if we hadn't first done bitmap_fold()
1159 * into tmp, then the @dst result would have been empty.
1160 *
1161 * If either of @orig or @relmap is empty (no set bits), then @dst
1162 * will be returned empty.
1163 *
1164 * If (as explained above) the only set bits in @orig are in positions
1165 * m where m >= W, (where W is the weight of @relmap) then @dst will
1166 * once again be returned empty.
1167 *
1168 * All bits in @dst not set by the above rule are cleared.
1169 */
1170void bitmap_onto(unsigned long *dst, const unsigned long *orig,
1171 const unsigned long *relmap, unsigned int bits)
1172{
1173 unsigned int n, m; /* same meaning as in above comment */
1174
1175 if (dst == orig) /* following doesn't handle inplace mappings */
1176 return;
1177 bitmap_zero(dst, bits);
1178
1179 /*
1180 * The following code is a more efficient, but less
1181 * obvious, equivalent to the loop:
1182 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
1183 * n = find_nth_bit(orig, bits, m);
1184 * if (test_bit(m, orig))
1185 * set_bit(n, dst);
1186 * }
1187 */
1188
1189 m = 0;
1190 for_each_set_bit(n, relmap, bits) {
1191 /* m == bitmap_pos_to_ord(relmap, n, bits) */
1192 if (test_bit(m, orig))
1193 set_bit(n, dst);
1194 m++;
1195 }
1196}
1197
1198/**
1199 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
1200 * @dst: resulting smaller bitmap
1201 * @orig: original larger bitmap
1202 * @sz: specified size
1203 * @nbits: number of bits in each of these bitmaps
1204 *
1205 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1206 * Clear all other bits in @dst. See further the comment and
1207 * Example [2] for bitmap_onto() for why and how to use this.
1208 */
1209void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1210 unsigned int sz, unsigned int nbits)
1211{
1212 unsigned int oldbit;
1213
1214 if (dst == orig) /* following doesn't handle inplace mappings */
1215 return;
1216 bitmap_zero(dst, nbits);
1217
1218 for_each_set_bit(oldbit, orig, nbits)
1219 set_bit(oldbit % sz, dst);
1220}
1221#endif /* CONFIG_NUMA */
1222
1223/*
1224 * Common code for bitmap_*_region() routines.
1225 * bitmap: array of unsigned longs corresponding to the bitmap
1226 * pos: the beginning of the region
1227 * order: region size (log base 2 of number of bits)
1228 * reg_op: operation(s) to perform on that region of bitmap
1229 *
1230 * Can set, verify and/or release a region of bits in a bitmap,
1231 * depending on which combination of REG_OP_* flag bits is set.
1232 *
1233 * A region of a bitmap is a sequence of bits in the bitmap, of
1234 * some size '1 << order' (a power of two), aligned to that same
1235 * '1 << order' power of two.
1236 *
1237 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1238 * Returns 0 in all other cases and reg_ops.
1239 */
1240
1241enum {
1242 REG_OP_ISFREE, /* true if region is all zero bits */
1243 REG_OP_ALLOC, /* set all bits in region */
1244 REG_OP_RELEASE, /* clear all bits in region */
1245};
1246
1247static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
1248{
1249 int nbits_reg; /* number of bits in region */
1250 int index; /* index first long of region in bitmap */
1251 int offset; /* bit offset region in bitmap[index] */
1252 int nlongs_reg; /* num longs spanned by region in bitmap */
1253 int nbitsinlong; /* num bits of region in each spanned long */
1254 unsigned long mask; /* bitmask for one long of region */
1255 int i; /* scans bitmap by longs */
1256 int ret = 0; /* return value */
1257
1258 /*
1259 * Either nlongs_reg == 1 (for small orders that fit in one long)
1260 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1261 */
1262 nbits_reg = 1 << order;
1263 index = pos / BITS_PER_LONG;
1264 offset = pos - (index * BITS_PER_LONG);
1265 nlongs_reg = BITS_TO_LONGS(nbits_reg);
1266 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1267
1268 /*
1269 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1270 * overflows if nbitsinlong == BITS_PER_LONG.
1271 */
1272 mask = (1UL << (nbitsinlong - 1));
1273 mask += mask - 1;
1274 mask <<= offset;
1275
1276 switch (reg_op) {
1277 case REG_OP_ISFREE:
1278 for (i = 0; i < nlongs_reg; i++) {
1279 if (bitmap[index + i] & mask)
1280 goto done;
1281 }
1282 ret = 1; /* all bits in region free (zero) */
1283 break;
1284
1285 case REG_OP_ALLOC:
1286 for (i = 0; i < nlongs_reg; i++)
1287 bitmap[index + i] |= mask;
1288 break;
1289
1290 case REG_OP_RELEASE:
1291 for (i = 0; i < nlongs_reg; i++)
1292 bitmap[index + i] &= ~mask;
1293 break;
1294 }
1295done:
1296 return ret;
1297}
1298
1299/**
1300 * bitmap_find_free_region - find a contiguous aligned mem region
1301 * @bitmap: array of unsigned longs corresponding to the bitmap
1302 * @bits: number of bits in the bitmap
1303 * @order: region size (log base 2 of number of bits) to find
1304 *
1305 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1306 * allocate them (set them to one). Only consider regions of length
1307 * a power (@order) of two, aligned to that power of two, which
1308 * makes the search algorithm much faster.
1309 *
1310 * Return the bit offset in bitmap of the allocated region,
1311 * or -errno on failure.
1312 */
1313int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
1314{
1315 unsigned int pos, end; /* scans bitmap by regions of size order */
1316
1317 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
1318 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1319 continue;
1320 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1321 return pos;
1322 }
1323 return -ENOMEM;
1324}
1325EXPORT_SYMBOL(bitmap_find_free_region);
1326
1327/**
1328 * bitmap_release_region - release allocated bitmap region
1329 * @bitmap: array of unsigned longs corresponding to the bitmap
1330 * @pos: beginning of bit region to release
1331 * @order: region size (log base 2 of number of bits) to release
1332 *
1333 * This is the complement to __bitmap_find_free_region() and releases
1334 * the found region (by clearing it in the bitmap).
1335 *
1336 * No return value.
1337 */
1338void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
1339{
1340 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1341}
1342EXPORT_SYMBOL(bitmap_release_region);
1343
1344/**
1345 * bitmap_allocate_region - allocate bitmap region
1346 * @bitmap: array of unsigned longs corresponding to the bitmap
1347 * @pos: beginning of bit region to allocate
1348 * @order: region size (log base 2 of number of bits) to allocate
1349 *
1350 * Allocate (set bits in) a specified region of a bitmap.
1351 *
1352 * Return 0 on success, or %-EBUSY if specified region wasn't
1353 * free (not all bits were zero).
1354 */
1355int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
1356{
1357 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1358 return -EBUSY;
1359 return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1360}
1361EXPORT_SYMBOL(bitmap_allocate_region);
1362
1363/**
1364 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1365 * @dst: destination buffer
1366 * @src: bitmap to copy
1367 * @nbits: number of bits in the bitmap
1368 *
1369 * Require nbits % BITS_PER_LONG == 0.
1370 */
1371#ifdef __BIG_ENDIAN
1372void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
1373{
1374 unsigned int i;
1375
1376 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1377 if (BITS_PER_LONG == 64)
1378 dst[i] = cpu_to_le64(src[i]);
1379 else
1380 dst[i] = cpu_to_le32(src[i]);
1381 }
1382}
1383EXPORT_SYMBOL(bitmap_copy_le);
1384#endif
1385
1386unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
1387{
1388 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
1389 flags);
1390}
1391EXPORT_SYMBOL(bitmap_alloc);
1392
1393unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
1394{
1395 return bitmap_alloc(nbits, flags | __GFP_ZERO);
1396}
1397EXPORT_SYMBOL(bitmap_zalloc);
1398
1399unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node)
1400{
1401 return kmalloc_array_node(BITS_TO_LONGS(nbits), sizeof(unsigned long),
1402 flags, node);
1403}
1404EXPORT_SYMBOL(bitmap_alloc_node);
1405
1406unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node)
1407{
1408 return bitmap_alloc_node(nbits, flags | __GFP_ZERO, node);
1409}
1410EXPORT_SYMBOL(bitmap_zalloc_node);
1411
1412void bitmap_free(const unsigned long *bitmap)
1413{
1414 kfree(bitmap);
1415}
1416EXPORT_SYMBOL(bitmap_free);
1417
1418static void devm_bitmap_free(void *data)
1419{
1420 unsigned long *bitmap = data;
1421
1422 bitmap_free(bitmap);
1423}
1424
1425unsigned long *devm_bitmap_alloc(struct device *dev,
1426 unsigned int nbits, gfp_t flags)
1427{
1428 unsigned long *bitmap;
1429 int ret;
1430
1431 bitmap = bitmap_alloc(nbits, flags);
1432 if (!bitmap)
1433 return NULL;
1434
1435 ret = devm_add_action_or_reset(dev, devm_bitmap_free, bitmap);
1436 if (ret)
1437 return NULL;
1438
1439 return bitmap;
1440}
1441EXPORT_SYMBOL_GPL(devm_bitmap_alloc);
1442
1443unsigned long *devm_bitmap_zalloc(struct device *dev,
1444 unsigned int nbits, gfp_t flags)
1445{
1446 return devm_bitmap_alloc(dev, nbits, flags | __GFP_ZERO);
1447}
1448EXPORT_SYMBOL_GPL(devm_bitmap_zalloc);
1449
1450#if BITS_PER_LONG == 64
1451/**
1452 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
1453 * @bitmap: array of unsigned longs, the destination bitmap
1454 * @buf: array of u32 (in host byte order), the source bitmap
1455 * @nbits: number of bits in @bitmap
1456 */
1457void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)
1458{
1459 unsigned int i, halfwords;
1460
1461 halfwords = DIV_ROUND_UP(nbits, 32);
1462 for (i = 0; i < halfwords; i++) {
1463 bitmap[i/2] = (unsigned long) buf[i];
1464 if (++i < halfwords)
1465 bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
1466 }
1467
1468 /* Clear tail bits in last word beyond nbits. */
1469 if (nbits % BITS_PER_LONG)
1470 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
1471}
1472EXPORT_SYMBOL(bitmap_from_arr32);
1473
1474/**
1475 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
1476 * @buf: array of u32 (in host byte order), the dest bitmap
1477 * @bitmap: array of unsigned longs, the source bitmap
1478 * @nbits: number of bits in @bitmap
1479 */
1480void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
1481{
1482 unsigned int i, halfwords;
1483
1484 halfwords = DIV_ROUND_UP(nbits, 32);
1485 for (i = 0; i < halfwords; i++) {
1486 buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
1487 if (++i < halfwords)
1488 buf[i] = (u32) (bitmap[i/2] >> 32);
1489 }
1490
1491 /* Clear tail bits in last element of array beyond nbits. */
1492 if (nbits % BITS_PER_LONG)
1493 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
1494}
1495EXPORT_SYMBOL(bitmap_to_arr32);
1496#endif
1497
1498#if (BITS_PER_LONG == 32) && defined(__BIG_ENDIAN)
1499/**
1500 * bitmap_from_arr64 - copy the contents of u64 array of bits to bitmap
1501 * @bitmap: array of unsigned longs, the destination bitmap
1502 * @buf: array of u64 (in host byte order), the source bitmap
1503 * @nbits: number of bits in @bitmap
1504 */
1505void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits)
1506{
1507 int n;
1508
1509 for (n = nbits; n > 0; n -= 64) {
1510 u64 val = *buf++;
1511
1512 *bitmap++ = val;
1513 if (n > 32)
1514 *bitmap++ = val >> 32;
1515 }
1516
1517 /*
1518 * Clear tail bits in the last word beyond nbits.
1519 *
1520 * Negative index is OK because here we point to the word next
1521 * to the last word of the bitmap, except for nbits == 0, which
1522 * is tested implicitly.
1523 */
1524 if (nbits % BITS_PER_LONG)
1525 bitmap[-1] &= BITMAP_LAST_WORD_MASK(nbits);
1526}
1527EXPORT_SYMBOL(bitmap_from_arr64);
1528
1529/**
1530 * bitmap_to_arr64 - copy the contents of bitmap to a u64 array of bits
1531 * @buf: array of u64 (in host byte order), the dest bitmap
1532 * @bitmap: array of unsigned longs, the source bitmap
1533 * @nbits: number of bits in @bitmap
1534 */
1535void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits)
1536{
1537 const unsigned long *end = bitmap + BITS_TO_LONGS(nbits);
1538
1539 while (bitmap < end) {
1540 *buf = *bitmap++;
1541 if (bitmap < end)
1542 *buf |= (u64)(*bitmap++) << 32;
1543 buf++;
1544 }
1545
1546 /* Clear tail bits in the last element of array beyond nbits. */
1547 if (nbits % 64)
1548 buf[-1] &= GENMASK_ULL((nbits - 1) % 64, 0);
1549}
1550EXPORT_SYMBOL(bitmap_to_arr64);
1551#endif