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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/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
48int __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 0;
55
56 if (bits % BITS_PER_LONG)
57 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
58 return 0;
59
60 return 1;
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
240int __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
278int __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
306int __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 1;
313
314 if (bits % BITS_PER_LONG)
315 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
316 return 1;
317 return 0;
318}
319EXPORT_SYMBOL(__bitmap_intersects);
320
321int __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 0;
328
329 if (bits % BITS_PER_LONG)
330 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
331 return 0;
332 return 1;
333}
334EXPORT_SYMBOL(__bitmap_subset);
335
336int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
337{
338 unsigned int k, lim = bits/BITS_PER_LONG;
339 int w = 0;
340
341 for (k = 0; k < lim; k++)
342 w += hweight_long(bitmap[k]);
343
344 if (bits % BITS_PER_LONG)
345 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
346
347 return w;
348}
349EXPORT_SYMBOL(__bitmap_weight);
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 printing & parsing functions: first version by Nadia Yvette Chambers,
434 * second version by Paul Jackson, third by Joe Korty.
435 */
436
437/**
438 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
439 *
440 * @ubuf: pointer to user buffer containing string.
441 * @ulen: buffer size in bytes. If string is smaller than this
442 * then it must be terminated with a \0.
443 * @maskp: pointer to bitmap array that will contain result.
444 * @nmaskbits: size of bitmap, in bits.
445 */
446int bitmap_parse_user(const char __user *ubuf,
447 unsigned int ulen, unsigned long *maskp,
448 int nmaskbits)
449{
450 char *buf;
451 int ret;
452
453 buf = memdup_user_nul(ubuf, ulen);
454 if (IS_ERR(buf))
455 return PTR_ERR(buf);
456
457 ret = bitmap_parse(buf, UINT_MAX, maskp, nmaskbits);
458
459 kfree(buf);
460 return ret;
461}
462EXPORT_SYMBOL(bitmap_parse_user);
463
464/**
465 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
466 * @list: indicates whether the bitmap must be list
467 * @buf: page aligned buffer into which string is placed
468 * @maskp: pointer to bitmap to convert
469 * @nmaskbits: size of bitmap, in bits
470 *
471 * Output format is a comma-separated list of decimal numbers and
472 * ranges if list is specified or hex digits grouped into comma-separated
473 * sets of 8 digits/set. Returns the number of characters written to buf.
474 *
475 * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
476 * area and that sufficient storage remains at @buf to accommodate the
477 * bitmap_print_to_pagebuf() output. Returns the number of characters
478 * actually printed to @buf, excluding terminating '\0'.
479 */
480int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
481 int nmaskbits)
482{
483 ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
484
485 return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
486 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
487}
488EXPORT_SYMBOL(bitmap_print_to_pagebuf);
489
490/*
491 * Region 9-38:4/10 describes the following bitmap structure:
492 * 0 9 12 18 38 N
493 * .........****......****......****..................
494 * ^ ^ ^ ^ ^
495 * start off group_len end nbits
496 */
497struct region {
498 unsigned int start;
499 unsigned int off;
500 unsigned int group_len;
501 unsigned int end;
502 unsigned int nbits;
503};
504
505static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
506{
507 unsigned int start;
508
509 for (start = r->start; start <= r->end; start += r->group_len)
510 bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
511}
512
513static int bitmap_check_region(const struct region *r)
514{
515 if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
516 return -EINVAL;
517
518 if (r->end >= r->nbits)
519 return -ERANGE;
520
521 return 0;
522}
523
524static const char *bitmap_getnum(const char *str, unsigned int *num,
525 unsigned int lastbit)
526{
527 unsigned long long n;
528 unsigned int len;
529
530 if (str[0] == 'N') {
531 *num = lastbit;
532 return str + 1;
533 }
534
535 len = _parse_integer(str, 10, &n);
536 if (!len)
537 return ERR_PTR(-EINVAL);
538 if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)
539 return ERR_PTR(-EOVERFLOW);
540
541 *num = n;
542 return str + len;
543}
544
545static inline bool end_of_str(char c)
546{
547 return c == '\0' || c == '\n';
548}
549
550static inline bool __end_of_region(char c)
551{
552 return isspace(c) || c == ',';
553}
554
555static inline bool end_of_region(char c)
556{
557 return __end_of_region(c) || end_of_str(c);
558}
559
560/*
561 * The format allows commas and whitespaces at the beginning
562 * of the region.
563 */
564static const char *bitmap_find_region(const char *str)
565{
566 while (__end_of_region(*str))
567 str++;
568
569 return end_of_str(*str) ? NULL : str;
570}
571
572static const char *bitmap_find_region_reverse(const char *start, const char *end)
573{
574 while (start <= end && __end_of_region(*end))
575 end--;
576
577 return end;
578}
579
580static const char *bitmap_parse_region(const char *str, struct region *r)
581{
582 unsigned int lastbit = r->nbits - 1;
583
584 if (!strncasecmp(str, "all", 3)) {
585 r->start = 0;
586 r->end = lastbit;
587 str += 3;
588
589 goto check_pattern;
590 }
591
592 str = bitmap_getnum(str, &r->start, lastbit);
593 if (IS_ERR(str))
594 return str;
595
596 if (end_of_region(*str))
597 goto no_end;
598
599 if (*str != '-')
600 return ERR_PTR(-EINVAL);
601
602 str = bitmap_getnum(str + 1, &r->end, lastbit);
603 if (IS_ERR(str))
604 return str;
605
606check_pattern:
607 if (end_of_region(*str))
608 goto no_pattern;
609
610 if (*str != ':')
611 return ERR_PTR(-EINVAL);
612
613 str = bitmap_getnum(str + 1, &r->off, lastbit);
614 if (IS_ERR(str))
615 return str;
616
617 if (*str != '/')
618 return ERR_PTR(-EINVAL);
619
620 return bitmap_getnum(str + 1, &r->group_len, lastbit);
621
622no_end:
623 r->end = r->start;
624no_pattern:
625 r->off = r->end + 1;
626 r->group_len = r->end + 1;
627
628 return end_of_str(*str) ? NULL : str;
629}
630
631/**
632 * bitmap_parselist - convert list format ASCII string to bitmap
633 * @buf: read user string from this buffer; must be terminated
634 * with a \0 or \n.
635 * @maskp: write resulting mask here
636 * @nmaskbits: number of bits in mask to be written
637 *
638 * Input format is a comma-separated list of decimal numbers and
639 * ranges. Consecutively set bits are shown as two hyphen-separated
640 * decimal numbers, the smallest and largest bit numbers set in
641 * the range.
642 * Optionally each range can be postfixed to denote that only parts of it
643 * should be set. The range will divided to groups of specific size.
644 * From each group will be used only defined amount of bits.
645 * Syntax: range:used_size/group_size
646 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
647 * The value 'N' can be used as a dynamically substituted token for the
648 * maximum allowed value; i.e (nmaskbits - 1). Keep in mind that it is
649 * dynamic, so if system changes cause the bitmap width to change, such
650 * as more cores in a CPU list, then any ranges using N will also change.
651 *
652 * Returns: 0 on success, -errno on invalid input strings. Error values:
653 *
654 * - ``-EINVAL``: wrong region format
655 * - ``-EINVAL``: invalid character in string
656 * - ``-ERANGE``: bit number specified too large for mask
657 * - ``-EOVERFLOW``: integer overflow in the input parameters
658 */
659int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
660{
661 struct region r;
662 long ret;
663
664 r.nbits = nmaskbits;
665 bitmap_zero(maskp, r.nbits);
666
667 while (buf) {
668 buf = bitmap_find_region(buf);
669 if (buf == NULL)
670 return 0;
671
672 buf = bitmap_parse_region(buf, &r);
673 if (IS_ERR(buf))
674 return PTR_ERR(buf);
675
676 ret = bitmap_check_region(&r);
677 if (ret)
678 return ret;
679
680 bitmap_set_region(&r, maskp);
681 }
682
683 return 0;
684}
685EXPORT_SYMBOL(bitmap_parselist);
686
687
688/**
689 * bitmap_parselist_user()
690 *
691 * @ubuf: pointer to user buffer containing string.
692 * @ulen: buffer size in bytes. If string is smaller than this
693 * then it must be terminated with a \0.
694 * @maskp: pointer to bitmap array that will contain result.
695 * @nmaskbits: size of bitmap, in bits.
696 *
697 * Wrapper for bitmap_parselist(), providing it with user buffer.
698 */
699int bitmap_parselist_user(const char __user *ubuf,
700 unsigned int ulen, unsigned long *maskp,
701 int nmaskbits)
702{
703 char *buf;
704 int ret;
705
706 buf = memdup_user_nul(ubuf, ulen);
707 if (IS_ERR(buf))
708 return PTR_ERR(buf);
709
710 ret = bitmap_parselist(buf, maskp, nmaskbits);
711
712 kfree(buf);
713 return ret;
714}
715EXPORT_SYMBOL(bitmap_parselist_user);
716
717static const char *bitmap_get_x32_reverse(const char *start,
718 const char *end, u32 *num)
719{
720 u32 ret = 0;
721 int c, i;
722
723 for (i = 0; i < 32; i += 4) {
724 c = hex_to_bin(*end--);
725 if (c < 0)
726 return ERR_PTR(-EINVAL);
727
728 ret |= c << i;
729
730 if (start > end || __end_of_region(*end))
731 goto out;
732 }
733
734 if (hex_to_bin(*end--) >= 0)
735 return ERR_PTR(-EOVERFLOW);
736out:
737 *num = ret;
738 return end;
739}
740
741/**
742 * bitmap_parse - convert an ASCII hex string into a bitmap.
743 * @start: pointer to buffer containing string.
744 * @buflen: buffer size in bytes. If string is smaller than this
745 * then it must be terminated with a \0 or \n. In that case,
746 * UINT_MAX may be provided instead of string length.
747 * @maskp: pointer to bitmap array that will contain result.
748 * @nmaskbits: size of bitmap, in bits.
749 *
750 * Commas group hex digits into chunks. Each chunk defines exactly 32
751 * bits of the resultant bitmask. No chunk may specify a value larger
752 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
753 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
754 * characters. Grouping such as "1,,5", ",44", "," or "" is allowed.
755 * Leading, embedded and trailing whitespace accepted.
756 */
757int bitmap_parse(const char *start, unsigned int buflen,
758 unsigned long *maskp, int nmaskbits)
759{
760 const char *end = strnchrnul(start, buflen, '\n') - 1;
761 int chunks = BITS_TO_U32(nmaskbits);
762 u32 *bitmap = (u32 *)maskp;
763 int unset_bit;
764 int chunk;
765
766 for (chunk = 0; ; chunk++) {
767 end = bitmap_find_region_reverse(start, end);
768 if (start > end)
769 break;
770
771 if (!chunks--)
772 return -EOVERFLOW;
773
774#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
775 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]);
776#else
777 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]);
778#endif
779 if (IS_ERR(end))
780 return PTR_ERR(end);
781 }
782
783 unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
784 if (unset_bit < nmaskbits) {
785 bitmap_clear(maskp, unset_bit, nmaskbits - unset_bit);
786 return 0;
787 }
788
789 if (find_next_bit(maskp, unset_bit, nmaskbits) != unset_bit)
790 return -EOVERFLOW;
791
792 return 0;
793}
794EXPORT_SYMBOL(bitmap_parse);
795
796/**
797 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
798 * @buf: pointer to a bitmap
799 * @pos: a bit position in @buf (0 <= @pos < @nbits)
800 * @nbits: number of valid bit positions in @buf
801 *
802 * Map the bit at position @pos in @buf (of length @nbits) to the
803 * ordinal of which set bit it is. If it is not set or if @pos
804 * is not a valid bit position, map to -1.
805 *
806 * If for example, just bits 4 through 7 are set in @buf, then @pos
807 * values 4 through 7 will get mapped to 0 through 3, respectively,
808 * and other @pos values will get mapped to -1. When @pos value 7
809 * gets mapped to (returns) @ord value 3 in this example, that means
810 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
811 *
812 * The bit positions 0 through @bits are valid positions in @buf.
813 */
814static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
815{
816 if (pos >= nbits || !test_bit(pos, buf))
817 return -1;
818
819 return __bitmap_weight(buf, pos);
820}
821
822/**
823 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
824 * @buf: pointer to bitmap
825 * @ord: ordinal bit position (n-th set bit, n >= 0)
826 * @nbits: number of valid bit positions in @buf
827 *
828 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
829 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord
830 * >= weight(buf), returns @nbits.
831 *
832 * If for example, just bits 4 through 7 are set in @buf, then @ord
833 * values 0 through 3 will get mapped to 4 through 7, respectively,
834 * and all other @ord values returns @nbits. When @ord value 3
835 * gets mapped to (returns) @pos value 7 in this example, that means
836 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
837 *
838 * The bit positions 0 through @nbits-1 are valid positions in @buf.
839 */
840unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits)
841{
842 unsigned int pos;
843
844 for (pos = find_first_bit(buf, nbits);
845 pos < nbits && ord;
846 pos = find_next_bit(buf, nbits, pos + 1))
847 ord--;
848
849 return pos;
850}
851
852/**
853 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
854 * @dst: remapped result
855 * @src: subset to be remapped
856 * @old: defines domain of map
857 * @new: defines range of map
858 * @nbits: number of bits in each of these bitmaps
859 *
860 * Let @old and @new define a mapping of bit positions, such that
861 * whatever position is held by the n-th set bit in @old is mapped
862 * to the n-th set bit in @new. In the more general case, allowing
863 * for the possibility that the weight 'w' of @new is less than the
864 * weight of @old, map the position of the n-th set bit in @old to
865 * the position of the m-th set bit in @new, where m == n % w.
866 *
867 * If either of the @old and @new bitmaps are empty, or if @src and
868 * @dst point to the same location, then this routine copies @src
869 * to @dst.
870 *
871 * The positions of unset bits in @old are mapped to themselves
872 * (the identify map).
873 *
874 * Apply the above specified mapping to @src, placing the result in
875 * @dst, clearing any bits previously set in @dst.
876 *
877 * For example, lets say that @old has bits 4 through 7 set, and
878 * @new has bits 12 through 15 set. This defines the mapping of bit
879 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
880 * bit positions unchanged. So if say @src comes into this routine
881 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
882 * 13 and 15 set.
883 */
884void bitmap_remap(unsigned long *dst, const unsigned long *src,
885 const unsigned long *old, const unsigned long *new,
886 unsigned int nbits)
887{
888 unsigned int oldbit, w;
889
890 if (dst == src) /* following doesn't handle inplace remaps */
891 return;
892 bitmap_zero(dst, nbits);
893
894 w = bitmap_weight(new, nbits);
895 for_each_set_bit(oldbit, src, nbits) {
896 int n = bitmap_pos_to_ord(old, oldbit, nbits);
897
898 if (n < 0 || w == 0)
899 set_bit(oldbit, dst); /* identity map */
900 else
901 set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst);
902 }
903}
904EXPORT_SYMBOL(bitmap_remap);
905
906/**
907 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
908 * @oldbit: bit position to be mapped
909 * @old: defines domain of map
910 * @new: defines range of map
911 * @bits: number of bits in each of these bitmaps
912 *
913 * Let @old and @new define a mapping of bit positions, such that
914 * whatever position is held by the n-th set bit in @old is mapped
915 * to the n-th set bit in @new. In the more general case, allowing
916 * for the possibility that the weight 'w' of @new is less than the
917 * weight of @old, map the position of the n-th set bit in @old to
918 * the position of the m-th set bit in @new, where m == n % w.
919 *
920 * The positions of unset bits in @old are mapped to themselves
921 * (the identify map).
922 *
923 * Apply the above specified mapping to bit position @oldbit, returning
924 * the new bit position.
925 *
926 * For example, lets say that @old has bits 4 through 7 set, and
927 * @new has bits 12 through 15 set. This defines the mapping of bit
928 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
929 * bit positions unchanged. So if say @oldbit is 5, then this routine
930 * returns 13.
931 */
932int bitmap_bitremap(int oldbit, const unsigned long *old,
933 const unsigned long *new, int bits)
934{
935 int w = bitmap_weight(new, bits);
936 int n = bitmap_pos_to_ord(old, oldbit, bits);
937 if (n < 0 || w == 0)
938 return oldbit;
939 else
940 return bitmap_ord_to_pos(new, n % w, bits);
941}
942EXPORT_SYMBOL(bitmap_bitremap);
943
944#ifdef CONFIG_NUMA
945/**
946 * bitmap_onto - translate one bitmap relative to another
947 * @dst: resulting translated bitmap
948 * @orig: original untranslated bitmap
949 * @relmap: bitmap relative to which translated
950 * @bits: number of bits in each of these bitmaps
951 *
952 * Set the n-th bit of @dst iff there exists some m such that the
953 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
954 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
955 * (If you understood the previous sentence the first time your
956 * read it, you're overqualified for your current job.)
957 *
958 * In other words, @orig is mapped onto (surjectively) @dst,
959 * using the map { <n, m> | the n-th bit of @relmap is the
960 * m-th set bit of @relmap }.
961 *
962 * Any set bits in @orig above bit number W, where W is the
963 * weight of (number of set bits in) @relmap are mapped nowhere.
964 * In particular, if for all bits m set in @orig, m >= W, then
965 * @dst will end up empty. In situations where the possibility
966 * of such an empty result is not desired, one way to avoid it is
967 * to use the bitmap_fold() operator, below, to first fold the
968 * @orig bitmap over itself so that all its set bits x are in the
969 * range 0 <= x < W. The bitmap_fold() operator does this by
970 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
971 *
972 * Example [1] for bitmap_onto():
973 * Let's say @relmap has bits 30-39 set, and @orig has bits
974 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
975 * @dst will have bits 31, 33, 35, 37 and 39 set.
976 *
977 * When bit 0 is set in @orig, it means turn on the bit in
978 * @dst corresponding to whatever is the first bit (if any)
979 * that is turned on in @relmap. Since bit 0 was off in the
980 * above example, we leave off that bit (bit 30) in @dst.
981 *
982 * When bit 1 is set in @orig (as in the above example), it
983 * means turn on the bit in @dst corresponding to whatever
984 * is the second bit that is turned on in @relmap. The second
985 * bit in @relmap that was turned on in the above example was
986 * bit 31, so we turned on bit 31 in @dst.
987 *
988 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
989 * because they were the 4th, 6th, 8th and 10th set bits
990 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
991 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
992 *
993 * When bit 11 is set in @orig, it means turn on the bit in
994 * @dst corresponding to whatever is the twelfth bit that is
995 * turned on in @relmap. In the above example, there were
996 * only ten bits turned on in @relmap (30..39), so that bit
997 * 11 was set in @orig had no affect on @dst.
998 *
999 * Example [2] for bitmap_fold() + bitmap_onto():
1000 * Let's say @relmap has these ten bits set::
1001 *
1002 * 40 41 42 43 45 48 53 61 74 95
1003 *
1004 * (for the curious, that's 40 plus the first ten terms of the
1005 * Fibonacci sequence.)
1006 *
1007 * Further lets say we use the following code, invoking
1008 * bitmap_fold() then bitmap_onto, as suggested above to
1009 * avoid the possibility of an empty @dst result::
1010 *
1011 * unsigned long *tmp; // a temporary bitmap's bits
1012 *
1013 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
1014 * bitmap_onto(dst, tmp, relmap, bits);
1015 *
1016 * Then this table shows what various values of @dst would be, for
1017 * various @orig's. I list the zero-based positions of each set bit.
1018 * The tmp column shows the intermediate result, as computed by
1019 * using bitmap_fold() to fold the @orig bitmap modulo ten
1020 * (the weight of @relmap):
1021 *
1022 * =============== ============== =================
1023 * @orig tmp @dst
1024 * 0 0 40
1025 * 1 1 41
1026 * 9 9 95
1027 * 10 0 40 [#f1]_
1028 * 1 3 5 7 1 3 5 7 41 43 48 61
1029 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
1030 * 0 9 18 27 0 9 8 7 40 61 74 95
1031 * 0 10 20 30 0 40
1032 * 0 11 22 33 0 1 2 3 40 41 42 43
1033 * 0 12 24 36 0 2 4 6 40 42 45 53
1034 * 78 102 211 1 2 8 41 42 74 [#f1]_
1035 * =============== ============== =================
1036 *
1037 * .. [#f1]
1038 *
1039 * For these marked lines, if we hadn't first done bitmap_fold()
1040 * into tmp, then the @dst result would have been empty.
1041 *
1042 * If either of @orig or @relmap is empty (no set bits), then @dst
1043 * will be returned empty.
1044 *
1045 * If (as explained above) the only set bits in @orig are in positions
1046 * m where m >= W, (where W is the weight of @relmap) then @dst will
1047 * once again be returned empty.
1048 *
1049 * All bits in @dst not set by the above rule are cleared.
1050 */
1051void bitmap_onto(unsigned long *dst, const unsigned long *orig,
1052 const unsigned long *relmap, unsigned int bits)
1053{
1054 unsigned int n, m; /* same meaning as in above comment */
1055
1056 if (dst == orig) /* following doesn't handle inplace mappings */
1057 return;
1058 bitmap_zero(dst, bits);
1059
1060 /*
1061 * The following code is a more efficient, but less
1062 * obvious, equivalent to the loop:
1063 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
1064 * n = bitmap_ord_to_pos(orig, m, bits);
1065 * if (test_bit(m, orig))
1066 * set_bit(n, dst);
1067 * }
1068 */
1069
1070 m = 0;
1071 for_each_set_bit(n, relmap, bits) {
1072 /* m == bitmap_pos_to_ord(relmap, n, bits) */
1073 if (test_bit(m, orig))
1074 set_bit(n, dst);
1075 m++;
1076 }
1077}
1078
1079/**
1080 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
1081 * @dst: resulting smaller bitmap
1082 * @orig: original larger bitmap
1083 * @sz: specified size
1084 * @nbits: number of bits in each of these bitmaps
1085 *
1086 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1087 * Clear all other bits in @dst. See further the comment and
1088 * Example [2] for bitmap_onto() for why and how to use this.
1089 */
1090void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1091 unsigned int sz, unsigned int nbits)
1092{
1093 unsigned int oldbit;
1094
1095 if (dst == orig) /* following doesn't handle inplace mappings */
1096 return;
1097 bitmap_zero(dst, nbits);
1098
1099 for_each_set_bit(oldbit, orig, nbits)
1100 set_bit(oldbit % sz, dst);
1101}
1102#endif /* CONFIG_NUMA */
1103
1104/*
1105 * Common code for bitmap_*_region() routines.
1106 * bitmap: array of unsigned longs corresponding to the bitmap
1107 * pos: the beginning of the region
1108 * order: region size (log base 2 of number of bits)
1109 * reg_op: operation(s) to perform on that region of bitmap
1110 *
1111 * Can set, verify and/or release a region of bits in a bitmap,
1112 * depending on which combination of REG_OP_* flag bits is set.
1113 *
1114 * A region of a bitmap is a sequence of bits in the bitmap, of
1115 * some size '1 << order' (a power of two), aligned to that same
1116 * '1 << order' power of two.
1117 *
1118 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1119 * Returns 0 in all other cases and reg_ops.
1120 */
1121
1122enum {
1123 REG_OP_ISFREE, /* true if region is all zero bits */
1124 REG_OP_ALLOC, /* set all bits in region */
1125 REG_OP_RELEASE, /* clear all bits in region */
1126};
1127
1128static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
1129{
1130 int nbits_reg; /* number of bits in region */
1131 int index; /* index first long of region in bitmap */
1132 int offset; /* bit offset region in bitmap[index] */
1133 int nlongs_reg; /* num longs spanned by region in bitmap */
1134 int nbitsinlong; /* num bits of region in each spanned long */
1135 unsigned long mask; /* bitmask for one long of region */
1136 int i; /* scans bitmap by longs */
1137 int ret = 0; /* return value */
1138
1139 /*
1140 * Either nlongs_reg == 1 (for small orders that fit in one long)
1141 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1142 */
1143 nbits_reg = 1 << order;
1144 index = pos / BITS_PER_LONG;
1145 offset = pos - (index * BITS_PER_LONG);
1146 nlongs_reg = BITS_TO_LONGS(nbits_reg);
1147 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1148
1149 /*
1150 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1151 * overflows if nbitsinlong == BITS_PER_LONG.
1152 */
1153 mask = (1UL << (nbitsinlong - 1));
1154 mask += mask - 1;
1155 mask <<= offset;
1156
1157 switch (reg_op) {
1158 case REG_OP_ISFREE:
1159 for (i = 0; i < nlongs_reg; i++) {
1160 if (bitmap[index + i] & mask)
1161 goto done;
1162 }
1163 ret = 1; /* all bits in region free (zero) */
1164 break;
1165
1166 case REG_OP_ALLOC:
1167 for (i = 0; i < nlongs_reg; i++)
1168 bitmap[index + i] |= mask;
1169 break;
1170
1171 case REG_OP_RELEASE:
1172 for (i = 0; i < nlongs_reg; i++)
1173 bitmap[index + i] &= ~mask;
1174 break;
1175 }
1176done:
1177 return ret;
1178}
1179
1180/**
1181 * bitmap_find_free_region - find a contiguous aligned mem region
1182 * @bitmap: array of unsigned longs corresponding to the bitmap
1183 * @bits: number of bits in the bitmap
1184 * @order: region size (log base 2 of number of bits) to find
1185 *
1186 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1187 * allocate them (set them to one). Only consider regions of length
1188 * a power (@order) of two, aligned to that power of two, which
1189 * makes the search algorithm much faster.
1190 *
1191 * Return the bit offset in bitmap of the allocated region,
1192 * or -errno on failure.
1193 */
1194int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
1195{
1196 unsigned int pos, end; /* scans bitmap by regions of size order */
1197
1198 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
1199 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1200 continue;
1201 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1202 return pos;
1203 }
1204 return -ENOMEM;
1205}
1206EXPORT_SYMBOL(bitmap_find_free_region);
1207
1208/**
1209 * bitmap_release_region - release allocated bitmap region
1210 * @bitmap: array of unsigned longs corresponding to the bitmap
1211 * @pos: beginning of bit region to release
1212 * @order: region size (log base 2 of number of bits) to release
1213 *
1214 * This is the complement to __bitmap_find_free_region() and releases
1215 * the found region (by clearing it in the bitmap).
1216 *
1217 * No return value.
1218 */
1219void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
1220{
1221 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1222}
1223EXPORT_SYMBOL(bitmap_release_region);
1224
1225/**
1226 * bitmap_allocate_region - allocate bitmap region
1227 * @bitmap: array of unsigned longs corresponding to the bitmap
1228 * @pos: beginning of bit region to allocate
1229 * @order: region size (log base 2 of number of bits) to allocate
1230 *
1231 * Allocate (set bits in) a specified region of a bitmap.
1232 *
1233 * Return 0 on success, or %-EBUSY if specified region wasn't
1234 * free (not all bits were zero).
1235 */
1236int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
1237{
1238 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1239 return -EBUSY;
1240 return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1241}
1242EXPORT_SYMBOL(bitmap_allocate_region);
1243
1244/**
1245 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1246 * @dst: destination buffer
1247 * @src: bitmap to copy
1248 * @nbits: number of bits in the bitmap
1249 *
1250 * Require nbits % BITS_PER_LONG == 0.
1251 */
1252#ifdef __BIG_ENDIAN
1253void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
1254{
1255 unsigned int i;
1256
1257 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1258 if (BITS_PER_LONG == 64)
1259 dst[i] = cpu_to_le64(src[i]);
1260 else
1261 dst[i] = cpu_to_le32(src[i]);
1262 }
1263}
1264EXPORT_SYMBOL(bitmap_copy_le);
1265#endif
1266
1267unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
1268{
1269 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
1270 flags);
1271}
1272EXPORT_SYMBOL(bitmap_alloc);
1273
1274unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
1275{
1276 return bitmap_alloc(nbits, flags | __GFP_ZERO);
1277}
1278EXPORT_SYMBOL(bitmap_zalloc);
1279
1280void bitmap_free(const unsigned long *bitmap)
1281{
1282 kfree(bitmap);
1283}
1284EXPORT_SYMBOL(bitmap_free);
1285
1286static void devm_bitmap_free(void *data)
1287{
1288 unsigned long *bitmap = data;
1289
1290 bitmap_free(bitmap);
1291}
1292
1293unsigned long *devm_bitmap_alloc(struct device *dev,
1294 unsigned int nbits, gfp_t flags)
1295{
1296 unsigned long *bitmap;
1297 int ret;
1298
1299 bitmap = bitmap_alloc(nbits, flags);
1300 if (!bitmap)
1301 return NULL;
1302
1303 ret = devm_add_action_or_reset(dev, devm_bitmap_free, bitmap);
1304 if (ret)
1305 return NULL;
1306
1307 return bitmap;
1308}
1309EXPORT_SYMBOL_GPL(devm_bitmap_alloc);
1310
1311unsigned long *devm_bitmap_zalloc(struct device *dev,
1312 unsigned int nbits, gfp_t flags)
1313{
1314 return devm_bitmap_alloc(dev, nbits, flags | __GFP_ZERO);
1315}
1316EXPORT_SYMBOL_GPL(devm_bitmap_zalloc);
1317
1318#if BITS_PER_LONG == 64
1319/**
1320 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
1321 * @bitmap: array of unsigned longs, the destination bitmap
1322 * @buf: array of u32 (in host byte order), the source bitmap
1323 * @nbits: number of bits in @bitmap
1324 */
1325void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)
1326{
1327 unsigned int i, halfwords;
1328
1329 halfwords = DIV_ROUND_UP(nbits, 32);
1330 for (i = 0; i < halfwords; i++) {
1331 bitmap[i/2] = (unsigned long) buf[i];
1332 if (++i < halfwords)
1333 bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
1334 }
1335
1336 /* Clear tail bits in last word beyond nbits. */
1337 if (nbits % BITS_PER_LONG)
1338 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
1339}
1340EXPORT_SYMBOL(bitmap_from_arr32);
1341
1342/**
1343 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
1344 * @buf: array of u32 (in host byte order), the dest bitmap
1345 * @bitmap: array of unsigned longs, the source bitmap
1346 * @nbits: number of bits in @bitmap
1347 */
1348void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
1349{
1350 unsigned int i, halfwords;
1351
1352 halfwords = DIV_ROUND_UP(nbits, 32);
1353 for (i = 0; i < halfwords; i++) {
1354 buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
1355 if (++i < halfwords)
1356 buf[i] = (u32) (bitmap[i/2] >> 32);
1357 }
1358
1359 /* Clear tail bits in last element of array beyond nbits. */
1360 if (nbits % BITS_PER_LONG)
1361 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
1362}
1363EXPORT_SYMBOL(bitmap_to_arr32);
1364
1365#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/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
351unsigned 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}
356EXPORT_SYMBOL(__bitmap_weight_andnot);
357
358void __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}
377EXPORT_SYMBOL(__bitmap_set);
378
379void __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}
398EXPORT_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 */
413unsigned 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;
421again:
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}
437EXPORT_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 */
457static 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 */
497void 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}
517EXPORT_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 */
545int 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}
555EXPORT_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 */
664void 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 */
703void 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
717unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
718{
719 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
720 flags);
721}
722EXPORT_SYMBOL(bitmap_alloc);
723
724unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
725{
726 return bitmap_alloc(nbits, flags | __GFP_ZERO);
727}
728EXPORT_SYMBOL(bitmap_zalloc);
729
730unsigned 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}
735EXPORT_SYMBOL(bitmap_alloc_node);
736
737unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node)
738{
739 return bitmap_alloc_node(nbits, flags | __GFP_ZERO, node);
740}
741EXPORT_SYMBOL(bitmap_zalloc_node);
742
743void bitmap_free(const unsigned long *bitmap)
744{
745 kfree(bitmap);
746}
747EXPORT_SYMBOL(bitmap_free);
748
749static void devm_bitmap_free(void *data)
750{
751 unsigned long *bitmap = data;
752
753 bitmap_free(bitmap);
754}
755
756unsigned 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}
772EXPORT_SYMBOL_GPL(devm_bitmap_alloc);
773
774unsigned 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}
779EXPORT_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 */
788void 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}
803EXPORT_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 */
811void 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}
826EXPORT_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 */
836void 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}
858EXPORT_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 */
866void 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}
881EXPORT_SYMBOL(bitmap_to_arr64);
882#endif