Loading...
1/*
2 * lib/bitmap.c
3 * Helper functions for bitmap.h.
4 *
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
7 */
8#include <linux/export.h>
9#include <linux/thread_info.h>
10#include <linux/ctype.h>
11#include <linux/errno.h>
12#include <linux/bitmap.h>
13#include <linux/bitops.h>
14#include <linux/bug.h>
15#include <asm/uaccess.h>
16
17/*
18 * bitmaps provide an array of bits, implemented using an an
19 * array of unsigned longs. The number of valid bits in a
20 * given bitmap does _not_ need to be an exact multiple of
21 * BITS_PER_LONG.
22 *
23 * The possible unused bits in the last, partially used word
24 * of a bitmap are 'don't care'. The implementation makes
25 * no particular effort to keep them zero. It ensures that
26 * their value will not affect the results of any operation.
27 * The bitmap operations that return Boolean (bitmap_empty,
28 * for example) or scalar (bitmap_weight, for example) results
29 * carefully filter out these unused bits from impacting their
30 * results.
31 *
32 * These operations actually hold to a slightly stronger rule:
33 * if you don't input any bitmaps to these ops that have some
34 * unused bits set, then they won't output any set unused bits
35 * in output bitmaps.
36 *
37 * The byte ordering of bitmaps is more natural on little
38 * endian architectures. See the big-endian headers
39 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
40 * for the best explanations of this ordering.
41 */
42
43int __bitmap_empty(const unsigned long *bitmap, int bits)
44{
45 int k, lim = bits/BITS_PER_LONG;
46 for (k = 0; k < lim; ++k)
47 if (bitmap[k])
48 return 0;
49
50 if (bits % BITS_PER_LONG)
51 if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
52 return 0;
53
54 return 1;
55}
56EXPORT_SYMBOL(__bitmap_empty);
57
58int __bitmap_full(const unsigned long *bitmap, int bits)
59{
60 int k, lim = bits/BITS_PER_LONG;
61 for (k = 0; k < lim; ++k)
62 if (~bitmap[k])
63 return 0;
64
65 if (bits % BITS_PER_LONG)
66 if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
67 return 0;
68
69 return 1;
70}
71EXPORT_SYMBOL(__bitmap_full);
72
73int __bitmap_equal(const unsigned long *bitmap1,
74 const unsigned long *bitmap2, int bits)
75{
76 int k, lim = bits/BITS_PER_LONG;
77 for (k = 0; k < lim; ++k)
78 if (bitmap1[k] != bitmap2[k])
79 return 0;
80
81 if (bits % BITS_PER_LONG)
82 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
83 return 0;
84
85 return 1;
86}
87EXPORT_SYMBOL(__bitmap_equal);
88
89void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
90{
91 int k, lim = bits/BITS_PER_LONG;
92 for (k = 0; k < lim; ++k)
93 dst[k] = ~src[k];
94
95 if (bits % BITS_PER_LONG)
96 dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
97}
98EXPORT_SYMBOL(__bitmap_complement);
99
100/**
101 * __bitmap_shift_right - logical right shift of the bits in a bitmap
102 * @dst : destination bitmap
103 * @src : source bitmap
104 * @shift : shift by this many bits
105 * @bits : bitmap size, in bits
106 *
107 * Shifting right (dividing) means moving bits in the MS -> LS bit
108 * direction. Zeros are fed into the vacated MS positions and the
109 * LS bits shifted off the bottom are lost.
110 */
111void __bitmap_shift_right(unsigned long *dst,
112 const unsigned long *src, int shift, int bits)
113{
114 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
115 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
116 unsigned long mask = (1UL << left) - 1;
117 for (k = 0; off + k < lim; ++k) {
118 unsigned long upper, lower;
119
120 /*
121 * If shift is not word aligned, take lower rem bits of
122 * word above and make them the top rem bits of result.
123 */
124 if (!rem || off + k + 1 >= lim)
125 upper = 0;
126 else {
127 upper = src[off + k + 1];
128 if (off + k + 1 == lim - 1 && left)
129 upper &= mask;
130 }
131 lower = src[off + k];
132 if (left && off + k == lim - 1)
133 lower &= mask;
134 dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
135 if (left && k == lim - 1)
136 dst[k] &= mask;
137 }
138 if (off)
139 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
140}
141EXPORT_SYMBOL(__bitmap_shift_right);
142
143
144/**
145 * __bitmap_shift_left - logical left shift of the bits in a bitmap
146 * @dst : destination bitmap
147 * @src : source bitmap
148 * @shift : shift by this many bits
149 * @bits : bitmap size, in bits
150 *
151 * Shifting left (multiplying) means moving bits in the LS -> MS
152 * direction. Zeros are fed into the vacated LS bit positions
153 * and those MS bits shifted off the top are lost.
154 */
155
156void __bitmap_shift_left(unsigned long *dst,
157 const unsigned long *src, int shift, int bits)
158{
159 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
160 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
161 for (k = lim - off - 1; k >= 0; --k) {
162 unsigned long upper, lower;
163
164 /*
165 * If shift is not word aligned, take upper rem bits of
166 * word below and make them the bottom rem bits of result.
167 */
168 if (rem && k > 0)
169 lower = src[k - 1];
170 else
171 lower = 0;
172 upper = src[k];
173 if (left && k == lim - 1)
174 upper &= (1UL << left) - 1;
175 dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
176 if (left && k + off == lim - 1)
177 dst[k + off] &= (1UL << left) - 1;
178 }
179 if (off)
180 memset(dst, 0, off*sizeof(unsigned long));
181}
182EXPORT_SYMBOL(__bitmap_shift_left);
183
184int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
185 const unsigned long *bitmap2, int bits)
186{
187 int k;
188 int nr = BITS_TO_LONGS(bits);
189 unsigned long result = 0;
190
191 for (k = 0; k < nr; k++)
192 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
193 return result != 0;
194}
195EXPORT_SYMBOL(__bitmap_and);
196
197void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
198 const unsigned long *bitmap2, int bits)
199{
200 int k;
201 int nr = BITS_TO_LONGS(bits);
202
203 for (k = 0; k < nr; k++)
204 dst[k] = bitmap1[k] | bitmap2[k];
205}
206EXPORT_SYMBOL(__bitmap_or);
207
208void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
209 const unsigned long *bitmap2, int bits)
210{
211 int k;
212 int nr = BITS_TO_LONGS(bits);
213
214 for (k = 0; k < nr; k++)
215 dst[k] = bitmap1[k] ^ bitmap2[k];
216}
217EXPORT_SYMBOL(__bitmap_xor);
218
219int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
220 const unsigned long *bitmap2, int bits)
221{
222 int k;
223 int nr = BITS_TO_LONGS(bits);
224 unsigned long result = 0;
225
226 for (k = 0; k < nr; k++)
227 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
228 return result != 0;
229}
230EXPORT_SYMBOL(__bitmap_andnot);
231
232int __bitmap_intersects(const unsigned long *bitmap1,
233 const unsigned long *bitmap2, int bits)
234{
235 int k, lim = bits/BITS_PER_LONG;
236 for (k = 0; k < lim; ++k)
237 if (bitmap1[k] & bitmap2[k])
238 return 1;
239
240 if (bits % BITS_PER_LONG)
241 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
242 return 1;
243 return 0;
244}
245EXPORT_SYMBOL(__bitmap_intersects);
246
247int __bitmap_subset(const unsigned long *bitmap1,
248 const unsigned long *bitmap2, int bits)
249{
250 int k, lim = bits/BITS_PER_LONG;
251 for (k = 0; k < lim; ++k)
252 if (bitmap1[k] & ~bitmap2[k])
253 return 0;
254
255 if (bits % BITS_PER_LONG)
256 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
257 return 0;
258 return 1;
259}
260EXPORT_SYMBOL(__bitmap_subset);
261
262int __bitmap_weight(const unsigned long *bitmap, int bits)
263{
264 int k, w = 0, lim = bits/BITS_PER_LONG;
265
266 for (k = 0; k < lim; k++)
267 w += hweight_long(bitmap[k]);
268
269 if (bits % BITS_PER_LONG)
270 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
271
272 return w;
273}
274EXPORT_SYMBOL(__bitmap_weight);
275
276void bitmap_set(unsigned long *map, int start, int nr)
277{
278 unsigned long *p = map + BIT_WORD(start);
279 const int size = start + nr;
280 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
281 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
282
283 while (nr - bits_to_set >= 0) {
284 *p |= mask_to_set;
285 nr -= bits_to_set;
286 bits_to_set = BITS_PER_LONG;
287 mask_to_set = ~0UL;
288 p++;
289 }
290 if (nr) {
291 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
292 *p |= mask_to_set;
293 }
294}
295EXPORT_SYMBOL(bitmap_set);
296
297void bitmap_clear(unsigned long *map, int start, int nr)
298{
299 unsigned long *p = map + BIT_WORD(start);
300 const int size = start + nr;
301 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
302 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
303
304 while (nr - bits_to_clear >= 0) {
305 *p &= ~mask_to_clear;
306 nr -= bits_to_clear;
307 bits_to_clear = BITS_PER_LONG;
308 mask_to_clear = ~0UL;
309 p++;
310 }
311 if (nr) {
312 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
313 *p &= ~mask_to_clear;
314 }
315}
316EXPORT_SYMBOL(bitmap_clear);
317
318/*
319 * bitmap_find_next_zero_area - find a contiguous aligned zero area
320 * @map: The address to base the search on
321 * @size: The bitmap size in bits
322 * @start: The bitnumber to start searching at
323 * @nr: The number of zeroed bits we're looking for
324 * @align_mask: Alignment mask for zero area
325 *
326 * The @align_mask should be one less than a power of 2; the effect is that
327 * the bit offset of all zero areas this function finds is multiples of that
328 * power of 2. A @align_mask of 0 means no alignment is required.
329 */
330unsigned long bitmap_find_next_zero_area(unsigned long *map,
331 unsigned long size,
332 unsigned long start,
333 unsigned int nr,
334 unsigned long align_mask)
335{
336 unsigned long index, end, i;
337again:
338 index = find_next_zero_bit(map, size, start);
339
340 /* Align allocation */
341 index = __ALIGN_MASK(index, align_mask);
342
343 end = index + nr;
344 if (end > size)
345 return end;
346 i = find_next_bit(map, end, index);
347 if (i < end) {
348 start = i + 1;
349 goto again;
350 }
351 return index;
352}
353EXPORT_SYMBOL(bitmap_find_next_zero_area);
354
355/*
356 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
357 * second version by Paul Jackson, third by Joe Korty.
358 */
359
360#define CHUNKSZ 32
361#define nbits_to_hold_value(val) fls(val)
362#define BASEDEC 10 /* fancier cpuset lists input in decimal */
363
364/**
365 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
366 * @buf: byte buffer into which string is placed
367 * @buflen: reserved size of @buf, in bytes
368 * @maskp: pointer to bitmap to convert
369 * @nmaskbits: size of bitmap, in bits
370 *
371 * Exactly @nmaskbits bits are displayed. Hex digits are grouped into
372 * comma-separated sets of eight digits per set. Returns the number of
373 * characters which were written to *buf, excluding the trailing \0.
374 */
375int bitmap_scnprintf(char *buf, unsigned int buflen,
376 const unsigned long *maskp, int nmaskbits)
377{
378 int i, word, bit, len = 0;
379 unsigned long val;
380 const char *sep = "";
381 int chunksz;
382 u32 chunkmask;
383
384 chunksz = nmaskbits & (CHUNKSZ - 1);
385 if (chunksz == 0)
386 chunksz = CHUNKSZ;
387
388 i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
389 for (; i >= 0; i -= CHUNKSZ) {
390 chunkmask = ((1ULL << chunksz) - 1);
391 word = i / BITS_PER_LONG;
392 bit = i % BITS_PER_LONG;
393 val = (maskp[word] >> bit) & chunkmask;
394 len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
395 (chunksz+3)/4, val);
396 chunksz = CHUNKSZ;
397 sep = ",";
398 }
399 return len;
400}
401EXPORT_SYMBOL(bitmap_scnprintf);
402
403/**
404 * __bitmap_parse - convert an ASCII hex string into a bitmap.
405 * @buf: pointer to buffer containing string.
406 * @buflen: buffer size in bytes. If string is smaller than this
407 * then it must be terminated with a \0.
408 * @is_user: location of buffer, 0 indicates kernel space
409 * @maskp: pointer to bitmap array that will contain result.
410 * @nmaskbits: size of bitmap, in bits.
411 *
412 * Commas group hex digits into chunks. Each chunk defines exactly 32
413 * bits of the resultant bitmask. No chunk may specify a value larger
414 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
415 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
416 * characters and for grouping errors such as "1,,5", ",44", "," and "".
417 * Leading and trailing whitespace accepted, but not embedded whitespace.
418 */
419int __bitmap_parse(const char *buf, unsigned int buflen,
420 int is_user, unsigned long *maskp,
421 int nmaskbits)
422{
423 int c, old_c, totaldigits, ndigits, nchunks, nbits;
424 u32 chunk;
425 const char __user __force *ubuf = (const char __user __force *)buf;
426
427 bitmap_zero(maskp, nmaskbits);
428
429 nchunks = nbits = totaldigits = c = 0;
430 do {
431 chunk = ndigits = 0;
432
433 /* Get the next chunk of the bitmap */
434 while (buflen) {
435 old_c = c;
436 if (is_user) {
437 if (__get_user(c, ubuf++))
438 return -EFAULT;
439 }
440 else
441 c = *buf++;
442 buflen--;
443 if (isspace(c))
444 continue;
445
446 /*
447 * If the last character was a space and the current
448 * character isn't '\0', we've got embedded whitespace.
449 * This is a no-no, so throw an error.
450 */
451 if (totaldigits && c && isspace(old_c))
452 return -EINVAL;
453
454 /* A '\0' or a ',' signal the end of the chunk */
455 if (c == '\0' || c == ',')
456 break;
457
458 if (!isxdigit(c))
459 return -EINVAL;
460
461 /*
462 * Make sure there are at least 4 free bits in 'chunk'.
463 * If not, this hexdigit will overflow 'chunk', so
464 * throw an error.
465 */
466 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
467 return -EOVERFLOW;
468
469 chunk = (chunk << 4) | hex_to_bin(c);
470 ndigits++; totaldigits++;
471 }
472 if (ndigits == 0)
473 return -EINVAL;
474 if (nchunks == 0 && chunk == 0)
475 continue;
476
477 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
478 *maskp |= chunk;
479 nchunks++;
480 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
481 if (nbits > nmaskbits)
482 return -EOVERFLOW;
483 } while (buflen && c == ',');
484
485 return 0;
486}
487EXPORT_SYMBOL(__bitmap_parse);
488
489/**
490 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
491 *
492 * @ubuf: pointer to user buffer containing string.
493 * @ulen: buffer size in bytes. If string is smaller than this
494 * then it must be terminated with a \0.
495 * @maskp: pointer to bitmap array that will contain result.
496 * @nmaskbits: size of bitmap, in bits.
497 *
498 * Wrapper for __bitmap_parse(), providing it with user buffer.
499 *
500 * We cannot have this as an inline function in bitmap.h because it needs
501 * linux/uaccess.h to get the access_ok() declaration and this causes
502 * cyclic dependencies.
503 */
504int bitmap_parse_user(const char __user *ubuf,
505 unsigned int ulen, unsigned long *maskp,
506 int nmaskbits)
507{
508 if (!access_ok(VERIFY_READ, ubuf, ulen))
509 return -EFAULT;
510 return __bitmap_parse((const char __force *)ubuf,
511 ulen, 1, maskp, nmaskbits);
512
513}
514EXPORT_SYMBOL(bitmap_parse_user);
515
516/*
517 * bscnl_emit(buf, buflen, rbot, rtop, bp)
518 *
519 * Helper routine for bitmap_scnlistprintf(). Write decimal number
520 * or range to buf, suppressing output past buf+buflen, with optional
521 * comma-prefix. Return len of what was written to *buf, excluding the
522 * trailing \0.
523 */
524static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
525{
526 if (len > 0)
527 len += scnprintf(buf + len, buflen - len, ",");
528 if (rbot == rtop)
529 len += scnprintf(buf + len, buflen - len, "%d", rbot);
530 else
531 len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
532 return len;
533}
534
535/**
536 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
537 * @buf: byte buffer into which string is placed
538 * @buflen: reserved size of @buf, in bytes
539 * @maskp: pointer to bitmap to convert
540 * @nmaskbits: size of bitmap, in bits
541 *
542 * Output format is a comma-separated list of decimal numbers and
543 * ranges. Consecutively set bits are shown as two hyphen-separated
544 * decimal numbers, the smallest and largest bit numbers set in
545 * the range. Output format is compatible with the format
546 * accepted as input by bitmap_parselist().
547 *
548 * The return value is the number of characters which were written to *buf
549 * excluding the trailing '\0', as per ISO C99's scnprintf.
550 */
551int bitmap_scnlistprintf(char *buf, unsigned int buflen,
552 const unsigned long *maskp, int nmaskbits)
553{
554 int len = 0;
555 /* current bit is 'cur', most recently seen range is [rbot, rtop] */
556 int cur, rbot, rtop;
557
558 if (buflen == 0)
559 return 0;
560 buf[0] = 0;
561
562 rbot = cur = find_first_bit(maskp, nmaskbits);
563 while (cur < nmaskbits) {
564 rtop = cur;
565 cur = find_next_bit(maskp, nmaskbits, cur+1);
566 if (cur >= nmaskbits || cur > rtop + 1) {
567 len = bscnl_emit(buf, buflen, rbot, rtop, len);
568 rbot = cur;
569 }
570 }
571 return len;
572}
573EXPORT_SYMBOL(bitmap_scnlistprintf);
574
575/**
576 * __bitmap_parselist - convert list format ASCII string to bitmap
577 * @buf: read nul-terminated user string from this buffer
578 * @buflen: buffer size in bytes. If string is smaller than this
579 * then it must be terminated with a \0.
580 * @is_user: location of buffer, 0 indicates kernel space
581 * @maskp: write resulting mask here
582 * @nmaskbits: number of bits in mask to be written
583 *
584 * Input format is a comma-separated list of decimal numbers and
585 * ranges. Consecutively set bits are shown as two hyphen-separated
586 * decimal numbers, the smallest and largest bit numbers set in
587 * the range.
588 *
589 * Returns 0 on success, -errno on invalid input strings.
590 * Error values:
591 * %-EINVAL: second number in range smaller than first
592 * %-EINVAL: invalid character in string
593 * %-ERANGE: bit number specified too large for mask
594 */
595static int __bitmap_parselist(const char *buf, unsigned int buflen,
596 int is_user, unsigned long *maskp,
597 int nmaskbits)
598{
599 unsigned a, b;
600 int c, old_c, totaldigits;
601 const char __user __force *ubuf = (const char __user __force *)buf;
602 int exp_digit, in_range;
603
604 totaldigits = c = 0;
605 bitmap_zero(maskp, nmaskbits);
606 do {
607 exp_digit = 1;
608 in_range = 0;
609 a = b = 0;
610
611 /* Get the next cpu# or a range of cpu#'s */
612 while (buflen) {
613 old_c = c;
614 if (is_user) {
615 if (__get_user(c, ubuf++))
616 return -EFAULT;
617 } else
618 c = *buf++;
619 buflen--;
620 if (isspace(c))
621 continue;
622
623 /*
624 * If the last character was a space and the current
625 * character isn't '\0', we've got embedded whitespace.
626 * This is a no-no, so throw an error.
627 */
628 if (totaldigits && c && isspace(old_c))
629 return -EINVAL;
630
631 /* A '\0' or a ',' signal the end of a cpu# or range */
632 if (c == '\0' || c == ',')
633 break;
634
635 if (c == '-') {
636 if (exp_digit || in_range)
637 return -EINVAL;
638 b = 0;
639 in_range = 1;
640 exp_digit = 1;
641 continue;
642 }
643
644 if (!isdigit(c))
645 return -EINVAL;
646
647 b = b * 10 + (c - '0');
648 if (!in_range)
649 a = b;
650 exp_digit = 0;
651 totaldigits++;
652 }
653 if (!(a <= b))
654 return -EINVAL;
655 if (b >= nmaskbits)
656 return -ERANGE;
657 while (a <= b) {
658 set_bit(a, maskp);
659 a++;
660 }
661 } while (buflen && c == ',');
662 return 0;
663}
664
665int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
666{
667 char *nl = strchr(bp, '\n');
668 int len;
669
670 if (nl)
671 len = nl - bp;
672 else
673 len = strlen(bp);
674
675 return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
676}
677EXPORT_SYMBOL(bitmap_parselist);
678
679
680/**
681 * bitmap_parselist_user()
682 *
683 * @ubuf: pointer to user buffer containing string.
684 * @ulen: buffer size in bytes. If string is smaller than this
685 * then it must be terminated with a \0.
686 * @maskp: pointer to bitmap array that will contain result.
687 * @nmaskbits: size of bitmap, in bits.
688 *
689 * Wrapper for bitmap_parselist(), providing it with user buffer.
690 *
691 * We cannot have this as an inline function in bitmap.h because it needs
692 * linux/uaccess.h to get the access_ok() declaration and this causes
693 * cyclic dependencies.
694 */
695int bitmap_parselist_user(const char __user *ubuf,
696 unsigned int ulen, unsigned long *maskp,
697 int nmaskbits)
698{
699 if (!access_ok(VERIFY_READ, ubuf, ulen))
700 return -EFAULT;
701 return __bitmap_parselist((const char __force *)ubuf,
702 ulen, 1, maskp, nmaskbits);
703}
704EXPORT_SYMBOL(bitmap_parselist_user);
705
706
707/**
708 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
709 * @buf: pointer to a bitmap
710 * @pos: a bit position in @buf (0 <= @pos < @bits)
711 * @bits: number of valid bit positions in @buf
712 *
713 * Map the bit at position @pos in @buf (of length @bits) to the
714 * ordinal of which set bit it is. If it is not set or if @pos
715 * is not a valid bit position, map to -1.
716 *
717 * If for example, just bits 4 through 7 are set in @buf, then @pos
718 * values 4 through 7 will get mapped to 0 through 3, respectively,
719 * and other @pos values will get mapped to 0. When @pos value 7
720 * gets mapped to (returns) @ord value 3 in this example, that means
721 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
722 *
723 * The bit positions 0 through @bits are valid positions in @buf.
724 */
725static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
726{
727 int i, ord;
728
729 if (pos < 0 || pos >= bits || !test_bit(pos, buf))
730 return -1;
731
732 i = find_first_bit(buf, bits);
733 ord = 0;
734 while (i < pos) {
735 i = find_next_bit(buf, bits, i + 1);
736 ord++;
737 }
738 BUG_ON(i != pos);
739
740 return ord;
741}
742
743/**
744 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
745 * @buf: pointer to bitmap
746 * @ord: ordinal bit position (n-th set bit, n >= 0)
747 * @bits: number of valid bit positions in @buf
748 *
749 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
750 * Value of @ord should be in range 0 <= @ord < weight(buf), else
751 * results are undefined.
752 *
753 * If for example, just bits 4 through 7 are set in @buf, then @ord
754 * values 0 through 3 will get mapped to 4 through 7, respectively,
755 * and all other @ord values return undefined values. When @ord value 3
756 * gets mapped to (returns) @pos value 7 in this example, that means
757 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
758 *
759 * The bit positions 0 through @bits are valid positions in @buf.
760 */
761int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
762{
763 int pos = 0;
764
765 if (ord >= 0 && ord < bits) {
766 int i;
767
768 for (i = find_first_bit(buf, bits);
769 i < bits && ord > 0;
770 i = find_next_bit(buf, bits, i + 1))
771 ord--;
772 if (i < bits && ord == 0)
773 pos = i;
774 }
775
776 return pos;
777}
778
779/**
780 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
781 * @dst: remapped result
782 * @src: subset to be remapped
783 * @old: defines domain of map
784 * @new: defines range of map
785 * @bits: number of bits in each of these bitmaps
786 *
787 * Let @old and @new define a mapping of bit positions, such that
788 * whatever position is held by the n-th set bit in @old is mapped
789 * to the n-th set bit in @new. In the more general case, allowing
790 * for the possibility that the weight 'w' of @new is less than the
791 * weight of @old, map the position of the n-th set bit in @old to
792 * the position of the m-th set bit in @new, where m == n % w.
793 *
794 * If either of the @old and @new bitmaps are empty, or if @src and
795 * @dst point to the same location, then this routine copies @src
796 * to @dst.
797 *
798 * The positions of unset bits in @old are mapped to themselves
799 * (the identify map).
800 *
801 * Apply the above specified mapping to @src, placing the result in
802 * @dst, clearing any bits previously set in @dst.
803 *
804 * For example, lets say that @old has bits 4 through 7 set, and
805 * @new has bits 12 through 15 set. This defines the mapping of bit
806 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
807 * bit positions unchanged. So if say @src comes into this routine
808 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
809 * 13 and 15 set.
810 */
811void bitmap_remap(unsigned long *dst, const unsigned long *src,
812 const unsigned long *old, const unsigned long *new,
813 int bits)
814{
815 int oldbit, w;
816
817 if (dst == src) /* following doesn't handle inplace remaps */
818 return;
819 bitmap_zero(dst, bits);
820
821 w = bitmap_weight(new, bits);
822 for_each_set_bit(oldbit, src, bits) {
823 int n = bitmap_pos_to_ord(old, oldbit, bits);
824
825 if (n < 0 || w == 0)
826 set_bit(oldbit, dst); /* identity map */
827 else
828 set_bit(bitmap_ord_to_pos(new, n % w, bits), dst);
829 }
830}
831EXPORT_SYMBOL(bitmap_remap);
832
833/**
834 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
835 * @oldbit: bit position to be mapped
836 * @old: defines domain of map
837 * @new: defines range of map
838 * @bits: number of bits in each of these bitmaps
839 *
840 * Let @old and @new define a mapping of bit positions, such that
841 * whatever position is held by the n-th set bit in @old is mapped
842 * to the n-th set bit in @new. In the more general case, allowing
843 * for the possibility that the weight 'w' of @new is less than the
844 * weight of @old, map the position of the n-th set bit in @old to
845 * the position of the m-th set bit in @new, where m == n % w.
846 *
847 * The positions of unset bits in @old are mapped to themselves
848 * (the identify map).
849 *
850 * Apply the above specified mapping to bit position @oldbit, returning
851 * the new bit position.
852 *
853 * For example, lets say that @old has bits 4 through 7 set, and
854 * @new has bits 12 through 15 set. This defines the mapping of bit
855 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
856 * bit positions unchanged. So if say @oldbit is 5, then this routine
857 * returns 13.
858 */
859int bitmap_bitremap(int oldbit, const unsigned long *old,
860 const unsigned long *new, int bits)
861{
862 int w = bitmap_weight(new, bits);
863 int n = bitmap_pos_to_ord(old, oldbit, bits);
864 if (n < 0 || w == 0)
865 return oldbit;
866 else
867 return bitmap_ord_to_pos(new, n % w, bits);
868}
869EXPORT_SYMBOL(bitmap_bitremap);
870
871/**
872 * bitmap_onto - translate one bitmap relative to another
873 * @dst: resulting translated bitmap
874 * @orig: original untranslated bitmap
875 * @relmap: bitmap relative to which translated
876 * @bits: number of bits in each of these bitmaps
877 *
878 * Set the n-th bit of @dst iff there exists some m such that the
879 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
880 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
881 * (If you understood the previous sentence the first time your
882 * read it, you're overqualified for your current job.)
883 *
884 * In other words, @orig is mapped onto (surjectively) @dst,
885 * using the the map { <n, m> | the n-th bit of @relmap is the
886 * m-th set bit of @relmap }.
887 *
888 * Any set bits in @orig above bit number W, where W is the
889 * weight of (number of set bits in) @relmap are mapped nowhere.
890 * In particular, if for all bits m set in @orig, m >= W, then
891 * @dst will end up empty. In situations where the possibility
892 * of such an empty result is not desired, one way to avoid it is
893 * to use the bitmap_fold() operator, below, to first fold the
894 * @orig bitmap over itself so that all its set bits x are in the
895 * range 0 <= x < W. The bitmap_fold() operator does this by
896 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
897 *
898 * Example [1] for bitmap_onto():
899 * Let's say @relmap has bits 30-39 set, and @orig has bits
900 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
901 * @dst will have bits 31, 33, 35, 37 and 39 set.
902 *
903 * When bit 0 is set in @orig, it means turn on the bit in
904 * @dst corresponding to whatever is the first bit (if any)
905 * that is turned on in @relmap. Since bit 0 was off in the
906 * above example, we leave off that bit (bit 30) in @dst.
907 *
908 * When bit 1 is set in @orig (as in the above example), it
909 * means turn on the bit in @dst corresponding to whatever
910 * is the second bit that is turned on in @relmap. The second
911 * bit in @relmap that was turned on in the above example was
912 * bit 31, so we turned on bit 31 in @dst.
913 *
914 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
915 * because they were the 4th, 6th, 8th and 10th set bits
916 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
917 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
918 *
919 * When bit 11 is set in @orig, it means turn on the bit in
920 * @dst corresponding to whatever is the twelfth bit that is
921 * turned on in @relmap. In the above example, there were
922 * only ten bits turned on in @relmap (30..39), so that bit
923 * 11 was set in @orig had no affect on @dst.
924 *
925 * Example [2] for bitmap_fold() + bitmap_onto():
926 * Let's say @relmap has these ten bits set:
927 * 40 41 42 43 45 48 53 61 74 95
928 * (for the curious, that's 40 plus the first ten terms of the
929 * Fibonacci sequence.)
930 *
931 * Further lets say we use the following code, invoking
932 * bitmap_fold() then bitmap_onto, as suggested above to
933 * avoid the possitility of an empty @dst result:
934 *
935 * unsigned long *tmp; // a temporary bitmap's bits
936 *
937 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
938 * bitmap_onto(dst, tmp, relmap, bits);
939 *
940 * Then this table shows what various values of @dst would be, for
941 * various @orig's. I list the zero-based positions of each set bit.
942 * The tmp column shows the intermediate result, as computed by
943 * using bitmap_fold() to fold the @orig bitmap modulo ten
944 * (the weight of @relmap).
945 *
946 * @orig tmp @dst
947 * 0 0 40
948 * 1 1 41
949 * 9 9 95
950 * 10 0 40 (*)
951 * 1 3 5 7 1 3 5 7 41 43 48 61
952 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
953 * 0 9 18 27 0 9 8 7 40 61 74 95
954 * 0 10 20 30 0 40
955 * 0 11 22 33 0 1 2 3 40 41 42 43
956 * 0 12 24 36 0 2 4 6 40 42 45 53
957 * 78 102 211 1 2 8 41 42 74 (*)
958 *
959 * (*) For these marked lines, if we hadn't first done bitmap_fold()
960 * into tmp, then the @dst result would have been empty.
961 *
962 * If either of @orig or @relmap is empty (no set bits), then @dst
963 * will be returned empty.
964 *
965 * If (as explained above) the only set bits in @orig are in positions
966 * m where m >= W, (where W is the weight of @relmap) then @dst will
967 * once again be returned empty.
968 *
969 * All bits in @dst not set by the above rule are cleared.
970 */
971void bitmap_onto(unsigned long *dst, const unsigned long *orig,
972 const unsigned long *relmap, int bits)
973{
974 int n, m; /* same meaning as in above comment */
975
976 if (dst == orig) /* following doesn't handle inplace mappings */
977 return;
978 bitmap_zero(dst, bits);
979
980 /*
981 * The following code is a more efficient, but less
982 * obvious, equivalent to the loop:
983 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
984 * n = bitmap_ord_to_pos(orig, m, bits);
985 * if (test_bit(m, orig))
986 * set_bit(n, dst);
987 * }
988 */
989
990 m = 0;
991 for_each_set_bit(n, relmap, bits) {
992 /* m == bitmap_pos_to_ord(relmap, n, bits) */
993 if (test_bit(m, orig))
994 set_bit(n, dst);
995 m++;
996 }
997}
998EXPORT_SYMBOL(bitmap_onto);
999
1000/**
1001 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
1002 * @dst: resulting smaller bitmap
1003 * @orig: original larger bitmap
1004 * @sz: specified size
1005 * @bits: number of bits in each of these bitmaps
1006 *
1007 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1008 * Clear all other bits in @dst. See further the comment and
1009 * Example [2] for bitmap_onto() for why and how to use this.
1010 */
1011void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1012 int sz, int bits)
1013{
1014 int oldbit;
1015
1016 if (dst == orig) /* following doesn't handle inplace mappings */
1017 return;
1018 bitmap_zero(dst, bits);
1019
1020 for_each_set_bit(oldbit, orig, bits)
1021 set_bit(oldbit % sz, dst);
1022}
1023EXPORT_SYMBOL(bitmap_fold);
1024
1025/*
1026 * Common code for bitmap_*_region() routines.
1027 * bitmap: array of unsigned longs corresponding to the bitmap
1028 * pos: the beginning of the region
1029 * order: region size (log base 2 of number of bits)
1030 * reg_op: operation(s) to perform on that region of bitmap
1031 *
1032 * Can set, verify and/or release a region of bits in a bitmap,
1033 * depending on which combination of REG_OP_* flag bits is set.
1034 *
1035 * A region of a bitmap is a sequence of bits in the bitmap, of
1036 * some size '1 << order' (a power of two), aligned to that same
1037 * '1 << order' power of two.
1038 *
1039 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1040 * Returns 0 in all other cases and reg_ops.
1041 */
1042
1043enum {
1044 REG_OP_ISFREE, /* true if region is all zero bits */
1045 REG_OP_ALLOC, /* set all bits in region */
1046 REG_OP_RELEASE, /* clear all bits in region */
1047};
1048
1049static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op)
1050{
1051 int nbits_reg; /* number of bits in region */
1052 int index; /* index first long of region in bitmap */
1053 int offset; /* bit offset region in bitmap[index] */
1054 int nlongs_reg; /* num longs spanned by region in bitmap */
1055 int nbitsinlong; /* num bits of region in each spanned long */
1056 unsigned long mask; /* bitmask for one long of region */
1057 int i; /* scans bitmap by longs */
1058 int ret = 0; /* return value */
1059
1060 /*
1061 * Either nlongs_reg == 1 (for small orders that fit in one long)
1062 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1063 */
1064 nbits_reg = 1 << order;
1065 index = pos / BITS_PER_LONG;
1066 offset = pos - (index * BITS_PER_LONG);
1067 nlongs_reg = BITS_TO_LONGS(nbits_reg);
1068 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1069
1070 /*
1071 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1072 * overflows if nbitsinlong == BITS_PER_LONG.
1073 */
1074 mask = (1UL << (nbitsinlong - 1));
1075 mask += mask - 1;
1076 mask <<= offset;
1077
1078 switch (reg_op) {
1079 case REG_OP_ISFREE:
1080 for (i = 0; i < nlongs_reg; i++) {
1081 if (bitmap[index + i] & mask)
1082 goto done;
1083 }
1084 ret = 1; /* all bits in region free (zero) */
1085 break;
1086
1087 case REG_OP_ALLOC:
1088 for (i = 0; i < nlongs_reg; i++)
1089 bitmap[index + i] |= mask;
1090 break;
1091
1092 case REG_OP_RELEASE:
1093 for (i = 0; i < nlongs_reg; i++)
1094 bitmap[index + i] &= ~mask;
1095 break;
1096 }
1097done:
1098 return ret;
1099}
1100
1101/**
1102 * bitmap_find_free_region - find a contiguous aligned mem region
1103 * @bitmap: array of unsigned longs corresponding to the bitmap
1104 * @bits: number of bits in the bitmap
1105 * @order: region size (log base 2 of number of bits) to find
1106 *
1107 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1108 * allocate them (set them to one). Only consider regions of length
1109 * a power (@order) of two, aligned to that power of two, which
1110 * makes the search algorithm much faster.
1111 *
1112 * Return the bit offset in bitmap of the allocated region,
1113 * or -errno on failure.
1114 */
1115int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
1116{
1117 int pos, end; /* scans bitmap by regions of size order */
1118
1119 for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) {
1120 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1121 continue;
1122 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1123 return pos;
1124 }
1125 return -ENOMEM;
1126}
1127EXPORT_SYMBOL(bitmap_find_free_region);
1128
1129/**
1130 * bitmap_release_region - release allocated bitmap region
1131 * @bitmap: array of unsigned longs corresponding to the bitmap
1132 * @pos: beginning of bit region to release
1133 * @order: region size (log base 2 of number of bits) to release
1134 *
1135 * This is the complement to __bitmap_find_free_region() and releases
1136 * the found region (by clearing it in the bitmap).
1137 *
1138 * No return value.
1139 */
1140void bitmap_release_region(unsigned long *bitmap, int pos, int order)
1141{
1142 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1143}
1144EXPORT_SYMBOL(bitmap_release_region);
1145
1146/**
1147 * bitmap_allocate_region - allocate bitmap region
1148 * @bitmap: array of unsigned longs corresponding to the bitmap
1149 * @pos: beginning of bit region to allocate
1150 * @order: region size (log base 2 of number of bits) to allocate
1151 *
1152 * Allocate (set bits in) a specified region of a bitmap.
1153 *
1154 * Return 0 on success, or %-EBUSY if specified region wasn't
1155 * free (not all bits were zero).
1156 */
1157int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
1158{
1159 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1160 return -EBUSY;
1161 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1162 return 0;
1163}
1164EXPORT_SYMBOL(bitmap_allocate_region);
1165
1166/**
1167 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1168 * @dst: destination buffer
1169 * @src: bitmap to copy
1170 * @nbits: number of bits in the bitmap
1171 *
1172 * Require nbits % BITS_PER_LONG == 0.
1173 */
1174void bitmap_copy_le(void *dst, const unsigned long *src, int nbits)
1175{
1176 unsigned long *d = dst;
1177 int i;
1178
1179 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1180 if (BITS_PER_LONG == 64)
1181 d[i] = cpu_to_le64(src[i]);
1182 else
1183 d[i] = cpu_to_le32(src[i]);
1184 }
1185}
1186EXPORT_SYMBOL(bitmap_copy_le);
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