1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * lib/bitmap.c
4 * Helper functions for bitmap.h.
5 */
6 #include <linux/export.h>
7 #include <linux/thread_info.h>
8 #include <linux/ctype.h>
9 #include <linux/errno.h>
10 #include <linux/bitmap.h>
11 #include <linux/bitops.h>
12 #include <linux/bug.h>
13 #include <linux/kernel.h>
14 #include <linux/mm.h>
15 #include <linux/slab.h>
16 #include <linux/string.h>
17 #include <linux/uaccess.h>
18
19 #include <asm/page.h>
20
21 #include "kstrtox.h"
22
23 /**
24 * DOC: bitmap introduction
25 *
26 * bitmaps provide an array of bits, implemented using an an
27 * array of unsigned longs. The number of valid bits in a
28 * given bitmap does _not_ need to be an exact multiple of
29 * BITS_PER_LONG.
30 *
31 * The possible unused bits in the last, partially used word
32 * of a bitmap are 'don't care'. The implementation makes
33 * no particular effort to keep them zero. It ensures that
34 * their value will not affect the results of any operation.
35 * The bitmap operations that return Boolean (bitmap_empty,
36 * for example) or scalar (bitmap_weight, for example) results
37 * carefully filter out these unused bits from impacting their
38 * results.
39 *
40 * The byte ordering of bitmaps is more natural on little
41 * endian architectures. See the big-endian headers
42 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
43 * for the best explanations of this ordering.
44 */
45
46 int __bitmap_equal(const unsigned long *bitmap1,
47 const unsigned long *bitmap2, unsigned int bits)
48 {
49 unsigned int k, lim = bits/BITS_PER_LONG;
50 for (k = 0; k < lim; ++k)
51 if (bitmap1[k] != bitmap2[k])
52 return 0;
53
54 if (bits % BITS_PER_LONG)
55 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
56 return 0;
57
58 return 1;
59 }
60 EXPORT_SYMBOL(__bitmap_equal);
61
62 bool __bitmap_or_equal(const unsigned long *bitmap1,
63 const unsigned long *bitmap2,
64 const unsigned long *bitmap3,
65 unsigned int bits)
66 {
67 unsigned int k, lim = bits / BITS_PER_LONG;
68 unsigned long tmp;
69
70 for (k = 0; k < lim; ++k) {
71 if ((bitmap1[k] | bitmap2[k]) != bitmap3[k])
72 return false;
73 }
74
75 if (!(bits % BITS_PER_LONG))
76 return true;
77
78 tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k];
79 return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0;
80 }
81
82 void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
83 {
84 unsigned int k, lim = BITS_TO_LONGS(bits);
85 for (k = 0; k < lim; ++k)
86 dst[k] = ~src[k];
87 }
88 EXPORT_SYMBOL(__bitmap_complement);
89
90 /**
91 * __bitmap_shift_right - logical right shift of the bits in a bitmap
92 * @dst : destination bitmap
93 * @src : source bitmap
94 * @shift : shift by this many bits
95 * @nbits : bitmap size, in bits
96 *
97 * Shifting right (dividing) means moving bits in the MS -> LS bit
98 * direction. Zeros are fed into the vacated MS positions and the
99 * LS bits shifted off the bottom are lost.
100 */
101 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
102 unsigned shift, unsigned nbits)
103 {
104 unsigned k, lim = BITS_TO_LONGS(nbits);
105 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
106 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
107 for (k = 0; off + k < lim; ++k) {
108 unsigned long upper, lower;
109
110 /*
111 * If shift is not word aligned, take lower rem bits of
112 * word above and make them the top rem bits of result.
113 */
114 if (!rem || off + k + 1 >= lim)
115 upper = 0;
116 else {
117 upper = src[off + k + 1];
118 if (off + k + 1 == lim - 1)
119 upper &= mask;
120 upper <<= (BITS_PER_LONG - rem);
121 }
122 lower = src[off + k];
123 if (off + k == lim - 1)
124 lower &= mask;
125 lower >>= rem;
126 dst[k] = lower | upper;
127 }
128 if (off)
129 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
130 }
131 EXPORT_SYMBOL(__bitmap_shift_right);
132
133
134 /**
135 * __bitmap_shift_left - logical left shift of the bits in a bitmap
136 * @dst : destination bitmap
137 * @src : source bitmap
138 * @shift : shift by this many bits
139 * @nbits : bitmap size, in bits
140 *
141 * Shifting left (multiplying) means moving bits in the LS -> MS
142 * direction. Zeros are fed into the vacated LS bit positions
143 * and those MS bits shifted off the top are lost.
144 */
145
146 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
147 unsigned int shift, unsigned int nbits)
148 {
149 int k;
150 unsigned int lim = BITS_TO_LONGS(nbits);
151 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
152 for (k = lim - off - 1; k >= 0; --k) {
153 unsigned long upper, lower;
154
155 /*
156 * If shift is not word aligned, take upper rem bits of
157 * word below and make them the bottom rem bits of result.
158 */
159 if (rem && k > 0)
160 lower = src[k - 1] >> (BITS_PER_LONG - rem);
161 else
162 lower = 0;
163 upper = src[k] << rem;
164 dst[k + off] = lower | upper;
165 }
166 if (off)
167 memset(dst, 0, off*sizeof(unsigned long));
168 }
169 EXPORT_SYMBOL(__bitmap_shift_left);
170
171 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
172 const unsigned long *bitmap2, unsigned int bits)
173 {
174 unsigned int k;
175 unsigned int lim = bits/BITS_PER_LONG;
176 unsigned long result = 0;
177
178 for (k = 0; k < lim; k++)
179 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
180 if (bits % BITS_PER_LONG)
181 result |= (dst[k] = bitmap1[k] & bitmap2[k] &
182 BITMAP_LAST_WORD_MASK(bits));
183 return result != 0;
184 }
185 EXPORT_SYMBOL(__bitmap_and);
186
187 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
188 const unsigned long *bitmap2, unsigned int bits)
189 {
190 unsigned int k;
191 unsigned int nr = BITS_TO_LONGS(bits);
192
193 for (k = 0; k < nr; k++)
194 dst[k] = bitmap1[k] | bitmap2[k];
195 }
196 EXPORT_SYMBOL(__bitmap_or);
197
198 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
199 const unsigned long *bitmap2, unsigned int bits)
200 {
201 unsigned int k;
202 unsigned int nr = BITS_TO_LONGS(bits);
203
204 for (k = 0; k < nr; k++)
205 dst[k] = bitmap1[k] ^ bitmap2[k];
206 }
207 EXPORT_SYMBOL(__bitmap_xor);
208
209 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
210 const unsigned long *bitmap2, unsigned int bits)
211 {
212 unsigned int k;
213 unsigned int lim = bits/BITS_PER_LONG;
214 unsigned long result = 0;
215
216 for (k = 0; k < lim; k++)
217 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
218 if (bits % BITS_PER_LONG)
219 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
220 BITMAP_LAST_WORD_MASK(bits));
221 return result != 0;
222 }
223 EXPORT_SYMBOL(__bitmap_andnot);
224
225 int __bitmap_intersects(const unsigned long *bitmap1,
226 const unsigned long *bitmap2, unsigned int bits)
227 {
228 unsigned int k, lim = bits/BITS_PER_LONG;
229 for (k = 0; k < lim; ++k)
230 if (bitmap1[k] & bitmap2[k])
231 return 1;
232
233 if (bits % BITS_PER_LONG)
234 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
235 return 1;
236 return 0;
237 }
238 EXPORT_SYMBOL(__bitmap_intersects);
239
240 int __bitmap_subset(const unsigned long *bitmap1,
241 const unsigned long *bitmap2, unsigned int bits)
242 {
243 unsigned int k, lim = bits/BITS_PER_LONG;
244 for (k = 0; k < lim; ++k)
245 if (bitmap1[k] & ~bitmap2[k])
246 return 0;
247
248 if (bits % BITS_PER_LONG)
249 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
250 return 0;
251 return 1;
252 }
253 EXPORT_SYMBOL(__bitmap_subset);
254
255 int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
256 {
257 unsigned int k, lim = bits/BITS_PER_LONG;
258 int w = 0;
259
260 for (k = 0; k < lim; k++)
261 w += hweight_long(bitmap[k]);
262
263 if (bits % BITS_PER_LONG)
264 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
265
266 return w;
267 }
268 EXPORT_SYMBOL(__bitmap_weight);
269
270 void __bitmap_set(unsigned long *map, unsigned int start, int len)
271 {
272 unsigned long *p = map + BIT_WORD(start);
273 const unsigned int size = start + len;
274 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
275 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
276
277 while (len - bits_to_set >= 0) {
278 *p |= mask_to_set;
279 len -= bits_to_set;
280 bits_to_set = BITS_PER_LONG;
281 mask_to_set = ~0UL;
282 p++;
283 }
284 if (len) {
285 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
286 *p |= mask_to_set;
287 }
288 }
289 EXPORT_SYMBOL(__bitmap_set);
290
291 void __bitmap_clear(unsigned long *map, unsigned int start, int len)
292 {
293 unsigned long *p = map + BIT_WORD(start);
294 const unsigned int size = start + len;
295 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
296 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
297
298 while (len - bits_to_clear >= 0) {
299 *p &= ~mask_to_clear;
300 len -= bits_to_clear;
301 bits_to_clear = BITS_PER_LONG;
302 mask_to_clear = ~0UL;
303 p++;
304 }
305 if (len) {
306 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
307 *p &= ~mask_to_clear;
308 }
309 }
310 EXPORT_SYMBOL(__bitmap_clear);
311
312 /**
313 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
314 * @map: The address to base the search on
315 * @size: The bitmap size in bits
316 * @start: The bitnumber to start searching at
317 * @nr: The number of zeroed bits we're looking for
318 * @align_mask: Alignment mask for zero area
319 * @align_offset: Alignment offset for zero area.
320 *
321 * The @align_mask should be one less than a power of 2; the effect is that
322 * the bit offset of all zero areas this function finds plus @align_offset
323 * is multiple of that power of 2.
324 */
325 unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
326 unsigned long size,
327 unsigned long start,
328 unsigned int nr,
329 unsigned long align_mask,
330 unsigned long align_offset)
331 {
332 unsigned long index, end, i;
333 again:
334 index = find_next_zero_bit(map, size, start);
335
336 /* Align allocation */
337 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
338
339 end = index + nr;
340 if (end > size)
341 return end;
342 i = find_next_bit(map, end, index);
343 if (i < end) {
344 start = i + 1;
345 goto again;
346 }
347 return index;
348 }
349 EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
350
351 /*
352 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
353 * second version by Paul Jackson, third by Joe Korty.
354 */
355
356 #define CHUNKSZ 32
357 #define nbits_to_hold_value(val) fls(val)
358 #define BASEDEC 10 /* fancier cpuset lists input in decimal */
359
360 /**
361 * __bitmap_parse - convert an ASCII hex string into a bitmap.
362 * @buf: pointer to buffer containing string.
363 * @buflen: buffer size in bytes. If string is smaller than this
364 * then it must be terminated with a \0.
365 * @is_user: location of buffer, 0 indicates kernel space
366 * @maskp: pointer to bitmap array that will contain result.
367 * @nmaskbits: size of bitmap, in bits.
368 *
369 * Commas group hex digits into chunks. Each chunk defines exactly 32
370 * bits of the resultant bitmask. No chunk may specify a value larger
371 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
372 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
373 * characters and for grouping errors such as "1,,5", ",44", "," and "".
374 * Leading and trailing whitespace accepted, but not embedded whitespace.
375 */
376 int __bitmap_parse(const char *buf, unsigned int buflen,
377 int is_user, unsigned long *maskp,
378 int nmaskbits)
379 {
380 int c, old_c, totaldigits, ndigits, nchunks, nbits;
381 u32 chunk;
382 const char __user __force *ubuf = (const char __user __force *)buf;
383
384 bitmap_zero(maskp, nmaskbits);
385
386 nchunks = nbits = totaldigits = c = 0;
387 do {
388 chunk = 0;
389 ndigits = totaldigits;
390
391 /* Get the next chunk of the bitmap */
392 while (buflen) {
393 old_c = c;
394 if (is_user) {
395 if (__get_user(c, ubuf++))
396 return -EFAULT;
397 }
398 else
399 c = *buf++;
400 buflen--;
401 if (isspace(c))
402 continue;
403
404 /*
405 * If the last character was a space and the current
406 * character isn't '\0', we've got embedded whitespace.
407 * This is a no-no, so throw an error.
408 */
409 if (totaldigits && c && isspace(old_c))
410 return -EINVAL;
411
412 /* A '\0' or a ',' signal the end of the chunk */
413 if (c == '\0' || c == ',')
414 break;
415
416 if (!isxdigit(c))
417 return -EINVAL;
418
419 /*
420 * Make sure there are at least 4 free bits in 'chunk'.
421 * If not, this hexdigit will overflow 'chunk', so
422 * throw an error.
423 */
424 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
425 return -EOVERFLOW;
426
427 chunk = (chunk << 4) | hex_to_bin(c);
428 totaldigits++;
429 }
430 if (ndigits == totaldigits)
431 return -EINVAL;
432 if (nchunks == 0 && chunk == 0)
433 continue;
434
435 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
436 *maskp |= chunk;
437 nchunks++;
438 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
439 if (nbits > nmaskbits)
440 return -EOVERFLOW;
441 } while (buflen && c == ',');
442
443 return 0;
444 }
445 EXPORT_SYMBOL(__bitmap_parse);
446
447 /**
448 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
449 *
450 * @ubuf: pointer to user buffer containing string.
451 * @ulen: buffer size in bytes. If string is smaller than this
452 * then it must be terminated with a \0.
453 * @maskp: pointer to bitmap array that will contain result.
454 * @nmaskbits: size of bitmap, in bits.
455 *
456 * Wrapper for __bitmap_parse(), providing it with user buffer.
457 *
458 * We cannot have this as an inline function in bitmap.h because it needs
459 * linux/uaccess.h to get the access_ok() declaration and this causes
460 * cyclic dependencies.
461 */
462 int bitmap_parse_user(const char __user *ubuf,
463 unsigned int ulen, unsigned long *maskp,
464 int nmaskbits)
465 {
466 if (!access_ok(ubuf, ulen))
467 return -EFAULT;
468 return __bitmap_parse((const char __force *)ubuf,
469 ulen, 1, maskp, nmaskbits);
470
471 }
472 EXPORT_SYMBOL(bitmap_parse_user);
473
474 /**
475 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
476 * @list: indicates whether the bitmap must be list
477 * @buf: page aligned buffer into which string is placed
478 * @maskp: pointer to bitmap to convert
479 * @nmaskbits: size of bitmap, in bits
480 *
481 * Output format is a comma-separated list of decimal numbers and
482 * ranges if list is specified or hex digits grouped into comma-separated
483 * sets of 8 digits/set. Returns the number of characters written to buf.
484 *
485 * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
486 * area and that sufficient storage remains at @buf to accommodate the
487 * bitmap_print_to_pagebuf() output. Returns the number of characters
488 * actually printed to @buf, excluding terminating '\0'.
489 */
490 int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
491 int nmaskbits)
492 {
493 ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
494
495 return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
496 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
497 }
498 EXPORT_SYMBOL(bitmap_print_to_pagebuf);
499
500 /*
501 * Region 9-38:4/10 describes the following bitmap structure:
502 * 0 9 12 18 38
503 * .........****......****......****......
504 * ^ ^ ^ ^
505 * start off group_len end
506 */
507 struct region {
508 unsigned int start;
509 unsigned int off;
510 unsigned int group_len;
511 unsigned int end;
512 };
513
514 static int bitmap_set_region(const struct region *r,
515 unsigned long *bitmap, int nbits)
516 {
517 unsigned int start;
518
519 if (r->end >= nbits)
520 return -ERANGE;
521
522 for (start = r->start; start <= r->end; start += r->group_len)
523 bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
524
525 return 0;
526 }
527
528 static int bitmap_check_region(const struct region *r)
529 {
530 if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
531 return -EINVAL;
532
533 return 0;
534 }
535
536 static const char *bitmap_getnum(const char *str, unsigned int *num)
537 {
538 unsigned long long n;
539 unsigned int len;
540
541 len = _parse_integer(str, 10, &n);
542 if (!len)
543 return ERR_PTR(-EINVAL);
544 if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)
545 return ERR_PTR(-EOVERFLOW);
546
547 *num = n;
548 return str + len;
549 }
550
551 static inline bool end_of_str(char c)
552 {
553 return c == '\0' || c == '\n';
554 }
555
556 static inline bool __end_of_region(char c)
557 {
558 return isspace(c) || c == ',';
559 }
560
561 static inline bool end_of_region(char c)
562 {
563 return __end_of_region(c) || end_of_str(c);
564 }
565
566 /*
567 * The format allows commas and whitespases at the beginning
568 * of the region.
569 */
570 static const char *bitmap_find_region(const char *str)
571 {
572 while (__end_of_region(*str))
573 str++;
574
575 return end_of_str(*str) ? NULL : str;
576 }
577
578 static const char *bitmap_parse_region(const char *str, struct region *r)
579 {
580 str = bitmap_getnum(str, &r->start);
581 if (IS_ERR(str))
582 return str;
583
584 if (end_of_region(*str))
585 goto no_end;
586
587 if (*str != '-')
588 return ERR_PTR(-EINVAL);
589
590 str = bitmap_getnum(str + 1, &r->end);
591 if (IS_ERR(str))
592 return str;
593
594 if (end_of_region(*str))
595 goto no_pattern;
596
597 if (*str != ':')
598 return ERR_PTR(-EINVAL);
599
600 str = bitmap_getnum(str + 1, &r->off);
601 if (IS_ERR(str))
602 return str;
603
604 if (*str != '/')
605 return ERR_PTR(-EINVAL);
606
607 return bitmap_getnum(str + 1, &r->group_len);
608
609 no_end:
610 r->end = r->start;
611 no_pattern:
612 r->off = r->end + 1;
613 r->group_len = r->end + 1;
614
615 return end_of_str(*str) ? NULL : str;
616 }
617
618 /**
619 * bitmap_parselist - convert list format ASCII string to bitmap
620 * @buf: read user string from this buffer; must be terminated
621 * with a \0 or \n.
622 * @maskp: write resulting mask here
623 * @nmaskbits: number of bits in mask to be written
624 *
625 * Input format is a comma-separated list of decimal numbers and
626 * ranges. Consecutively set bits are shown as two hyphen-separated
627 * decimal numbers, the smallest and largest bit numbers set in
628 * the range.
629 * Optionally each range can be postfixed to denote that only parts of it
630 * should be set. The range will divided to groups of specific size.
631 * From each group will be used only defined amount of bits.
632 * Syntax: range:used_size/group_size
633 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
634 *
635 * Returns: 0 on success, -errno on invalid input strings. Error values:
636 *
637 * - ``-EINVAL``: wrong region format
638 * - ``-EINVAL``: invalid character in string
639 * - ``-ERANGE``: bit number specified too large for mask
640 * - ``-EOVERFLOW``: integer overflow in the input parameters
641 */
642 int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
643 {
644 struct region r;
645 long ret;
646
647 bitmap_zero(maskp, nmaskbits);
648
649 while (buf) {
650 buf = bitmap_find_region(buf);
651 if (buf == NULL)
652 return 0;
653
654 buf = bitmap_parse_region(buf, &r);
655 if (IS_ERR(buf))
656 return PTR_ERR(buf);
657
658 ret = bitmap_check_region(&r);
659 if (ret)
660 return ret;
661
662 ret = bitmap_set_region(&r, maskp, nmaskbits);
663 if (ret)
664 return ret;
665 }
666
667 return 0;
668 }
669 EXPORT_SYMBOL(bitmap_parselist);
670
671
672 /**
673 * bitmap_parselist_user()
674 *
675 * @ubuf: pointer to user buffer containing string.
676 * @ulen: buffer size in bytes. If string is smaller than this
677 * then it must be terminated with a \0.
678 * @maskp: pointer to bitmap array that will contain result.
679 * @nmaskbits: size of bitmap, in bits.
680 *
681 * Wrapper for bitmap_parselist(), providing it with user buffer.
682 */
683 int bitmap_parselist_user(const char __user *ubuf,
684 unsigned int ulen, unsigned long *maskp,
685 int nmaskbits)
686 {
687 char *buf;
688 int ret;
689
690 buf = memdup_user_nul(ubuf, ulen);
691 if (IS_ERR(buf))
692 return PTR_ERR(buf);
693
694 ret = bitmap_parselist(buf, maskp, nmaskbits);
695
696 kfree(buf);
697 return ret;
698 }
699 EXPORT_SYMBOL(bitmap_parselist_user);
700
701
702 #ifdef CONFIG_NUMA
703 /**
704 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
705 * @buf: pointer to a bitmap
706 * @pos: a bit position in @buf (0 <= @pos < @nbits)
707 * @nbits: number of valid bit positions in @buf
708 *
709 * Map the bit at position @pos in @buf (of length @nbits) to the
710 * ordinal of which set bit it is. If it is not set or if @pos
711 * is not a valid bit position, map to -1.
712 *
713 * If for example, just bits 4 through 7 are set in @buf, then @pos
714 * values 4 through 7 will get mapped to 0 through 3, respectively,
715 * and other @pos values will get mapped to -1. When @pos value 7
716 * gets mapped to (returns) @ord value 3 in this example, that means
717 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
718 *
719 * The bit positions 0 through @bits are valid positions in @buf.
720 */
721 static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
722 {
723 if (pos >= nbits || !test_bit(pos, buf))
724 return -1;
725
726 return __bitmap_weight(buf, pos);
727 }
728
729 /**
730 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
731 * @buf: pointer to bitmap
732 * @ord: ordinal bit position (n-th set bit, n >= 0)
733 * @nbits: number of valid bit positions in @buf
734 *
735 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
736 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord
737 * >= weight(buf), returns @nbits.
738 *
739 * If for example, just bits 4 through 7 are set in @buf, then @ord
740 * values 0 through 3 will get mapped to 4 through 7, respectively,
741 * and all other @ord values returns @nbits. When @ord value 3
742 * gets mapped to (returns) @pos value 7 in this example, that means
743 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
744 *
745 * The bit positions 0 through @nbits-1 are valid positions in @buf.
746 */
747 unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits)
748 {
749 unsigned int pos;
750
751 for (pos = find_first_bit(buf, nbits);
752 pos < nbits && ord;
753 pos = find_next_bit(buf, nbits, pos + 1))
754 ord--;
755
756 return pos;
757 }
758
759 /**
760 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
761 * @dst: remapped result
762 * @src: subset to be remapped
763 * @old: defines domain of map
764 * @new: defines range of map
765 * @nbits: number of bits in each of these bitmaps
766 *
767 * Let @old and @new define a mapping of bit positions, such that
768 * whatever position is held by the n-th set bit in @old is mapped
769 * to the n-th set bit in @new. In the more general case, allowing
770 * for the possibility that the weight 'w' of @new is less than the
771 * weight of @old, map the position of the n-th set bit in @old to
772 * the position of the m-th set bit in @new, where m == n % w.
773 *
774 * If either of the @old and @new bitmaps are empty, or if @src and
775 * @dst point to the same location, then this routine copies @src
776 * to @dst.
777 *
778 * The positions of unset bits in @old are mapped to themselves
779 * (the identify map).
780 *
781 * Apply the above specified mapping to @src, placing the result in
782 * @dst, clearing any bits previously set in @dst.
783 *
784 * For example, lets say that @old has bits 4 through 7 set, and
785 * @new has bits 12 through 15 set. This defines the mapping of bit
786 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
787 * bit positions unchanged. So if say @src comes into this routine
788 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
789 * 13 and 15 set.
790 */
791 void bitmap_remap(unsigned long *dst, const unsigned long *src,
792 const unsigned long *old, const unsigned long *new,
793 unsigned int nbits)
794 {
795 unsigned int oldbit, w;
796
797 if (dst == src) /* following doesn't handle inplace remaps */
798 return;
799 bitmap_zero(dst, nbits);
800
801 w = bitmap_weight(new, nbits);
802 for_each_set_bit(oldbit, src, nbits) {
803 int n = bitmap_pos_to_ord(old, oldbit, nbits);
804
805 if (n < 0 || w == 0)
806 set_bit(oldbit, dst); /* identity map */
807 else
808 set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst);
809 }
810 }
811
812 /**
813 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
814 * @oldbit: bit position to be mapped
815 * @old: defines domain of map
816 * @new: defines range of map
817 * @bits: number of bits in each of these bitmaps
818 *
819 * Let @old and @new define a mapping of bit positions, such that
820 * whatever position is held by the n-th set bit in @old is mapped
821 * to the n-th set bit in @new. In the more general case, allowing
822 * for the possibility that the weight 'w' of @new is less than the
823 * weight of @old, map the position of the n-th set bit in @old to
824 * the position of the m-th set bit in @new, where m == n % w.
825 *
826 * The positions of unset bits in @old are mapped to themselves
827 * (the identify map).
828 *
829 * Apply the above specified mapping to bit position @oldbit, returning
830 * the new bit position.
831 *
832 * For example, lets say that @old has bits 4 through 7 set, and
833 * @new has bits 12 through 15 set. This defines the mapping of bit
834 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
835 * bit positions unchanged. So if say @oldbit is 5, then this routine
836 * returns 13.
837 */
838 int bitmap_bitremap(int oldbit, const unsigned long *old,
839 const unsigned long *new, int bits)
840 {
841 int w = bitmap_weight(new, bits);
842 int n = bitmap_pos_to_ord(old, oldbit, bits);
843 if (n < 0 || w == 0)
844 return oldbit;
845 else
846 return bitmap_ord_to_pos(new, n % w, bits);
847 }
848
849 /**
850 * bitmap_onto - translate one bitmap relative to another
851 * @dst: resulting translated bitmap
852 * @orig: original untranslated bitmap
853 * @relmap: bitmap relative to which translated
854 * @bits: number of bits in each of these bitmaps
855 *
856 * Set the n-th bit of @dst iff there exists some m such that the
857 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
858 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
859 * (If you understood the previous sentence the first time your
860 * read it, you're overqualified for your current job.)
861 *
862 * In other words, @orig is mapped onto (surjectively) @dst,
863 * using the map { <n, m> | the n-th bit of @relmap is the
864 * m-th set bit of @relmap }.
865 *
866 * Any set bits in @orig above bit number W, where W is the
867 * weight of (number of set bits in) @relmap are mapped nowhere.
868 * In particular, if for all bits m set in @orig, m >= W, then
869 * @dst will end up empty. In situations where the possibility
870 * of such an empty result is not desired, one way to avoid it is
871 * to use the bitmap_fold() operator, below, to first fold the
872 * @orig bitmap over itself so that all its set bits x are in the
873 * range 0 <= x < W. The bitmap_fold() operator does this by
874 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
875 *
876 * Example [1] for bitmap_onto():
877 * Let's say @relmap has bits 30-39 set, and @orig has bits
878 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
879 * @dst will have bits 31, 33, 35, 37 and 39 set.
880 *
881 * When bit 0 is set in @orig, it means turn on the bit in
882 * @dst corresponding to whatever is the first bit (if any)
883 * that is turned on in @relmap. Since bit 0 was off in the
884 * above example, we leave off that bit (bit 30) in @dst.
885 *
886 * When bit 1 is set in @orig (as in the above example), it
887 * means turn on the bit in @dst corresponding to whatever
888 * is the second bit that is turned on in @relmap. The second
889 * bit in @relmap that was turned on in the above example was
890 * bit 31, so we turned on bit 31 in @dst.
891 *
892 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
893 * because they were the 4th, 6th, 8th and 10th set bits
894 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
895 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
896 *
897 * When bit 11 is set in @orig, it means turn on the bit in
898 * @dst corresponding to whatever is the twelfth bit that is
899 * turned on in @relmap. In the above example, there were
900 * only ten bits turned on in @relmap (30..39), so that bit
901 * 11 was set in @orig had no affect on @dst.
902 *
903 * Example [2] for bitmap_fold() + bitmap_onto():
904 * Let's say @relmap has these ten bits set::
905 *
906 * 40 41 42 43 45 48 53 61 74 95
907 *
908 * (for the curious, that's 40 plus the first ten terms of the
909 * Fibonacci sequence.)
910 *
911 * Further lets say we use the following code, invoking
912 * bitmap_fold() then bitmap_onto, as suggested above to
913 * avoid the possibility of an empty @dst result::
914 *
915 * unsigned long *tmp; // a temporary bitmap's bits
916 *
917 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
918 * bitmap_onto(dst, tmp, relmap, bits);
919 *
920 * Then this table shows what various values of @dst would be, for
921 * various @orig's. I list the zero-based positions of each set bit.
922 * The tmp column shows the intermediate result, as computed by
923 * using bitmap_fold() to fold the @orig bitmap modulo ten
924 * (the weight of @relmap):
925 *
926 * =============== ============== =================
927 * @orig tmp @dst
928 * 0 0 40
929 * 1 1 41
930 * 9 9 95
931 * 10 0 40 [#f1]_
932 * 1 3 5 7 1 3 5 7 41 43 48 61
933 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
934 * 0 9 18 27 0 9 8 7 40 61 74 95
935 * 0 10 20 30 0 40
936 * 0 11 22 33 0 1 2 3 40 41 42 43
937 * 0 12 24 36 0 2 4 6 40 42 45 53
938 * 78 102 211 1 2 8 41 42 74 [#f1]_
939 * =============== ============== =================
940 *
941 * .. [#f1]
942 *
943 * For these marked lines, if we hadn't first done bitmap_fold()
944 * into tmp, then the @dst result would have been empty.
945 *
946 * If either of @orig or @relmap is empty (no set bits), then @dst
947 * will be returned empty.
948 *
949 * If (as explained above) the only set bits in @orig are in positions
950 * m where m >= W, (where W is the weight of @relmap) then @dst will
951 * once again be returned empty.
952 *
953 * All bits in @dst not set by the above rule are cleared.
954 */
955 void bitmap_onto(unsigned long *dst, const unsigned long *orig,
956 const unsigned long *relmap, unsigned int bits)
957 {
958 unsigned int n, m; /* same meaning as in above comment */
959
960 if (dst == orig) /* following doesn't handle inplace mappings */
961 return;
962 bitmap_zero(dst, bits);
963
964 /*
965 * The following code is a more efficient, but less
966 * obvious, equivalent to the loop:
967 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
968 * n = bitmap_ord_to_pos(orig, m, bits);
969 * if (test_bit(m, orig))
970 * set_bit(n, dst);
971 * }
972 */
973
974 m = 0;
975 for_each_set_bit(n, relmap, bits) {
976 /* m == bitmap_pos_to_ord(relmap, n, bits) */
977 if (test_bit(m, orig))
978 set_bit(n, dst);
979 m++;
980 }
981 }
982
983 /**
984 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
985 * @dst: resulting smaller bitmap
986 * @orig: original larger bitmap
987 * @sz: specified size
988 * @nbits: number of bits in each of these bitmaps
989 *
990 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
991 * Clear all other bits in @dst. See further the comment and
992 * Example [2] for bitmap_onto() for why and how to use this.
993 */
994 void bitmap_fold(unsigned long *dst, const unsigned long *orig,
995 unsigned int sz, unsigned int nbits)
996 {
997 unsigned int oldbit;
998
999 if (dst == orig) /* following doesn't handle inplace mappings */
1000 return;
1001 bitmap_zero(dst, nbits);
1002
1003 for_each_set_bit(oldbit, orig, nbits)
1004 set_bit(oldbit % sz, dst);
1005 }
1006 #endif /* CONFIG_NUMA */
1007
1008 /*
1009 * Common code for bitmap_*_region() routines.
1010 * bitmap: array of unsigned longs corresponding to the bitmap
1011 * pos: the beginning of the region
1012 * order: region size (log base 2 of number of bits)
1013 * reg_op: operation(s) to perform on that region of bitmap
1014 *
1015 * Can set, verify and/or release a region of bits in a bitmap,
1016 * depending on which combination of REG_OP_* flag bits is set.
1017 *
1018 * A region of a bitmap is a sequence of bits in the bitmap, of
1019 * some size '1 << order' (a power of two), aligned to that same
1020 * '1 << order' power of two.
1021 *
1022 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1023 * Returns 0 in all other cases and reg_ops.
1024 */
1025
1026 enum {
1027 REG_OP_ISFREE, /* true if region is all zero bits */
1028 REG_OP_ALLOC, /* set all bits in region */
1029 REG_OP_RELEASE, /* clear all bits in region */
1030 };
1031
1032 static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
1033 {
1034 int nbits_reg; /* number of bits in region */
1035 int index; /* index first long of region in bitmap */
1036 int offset; /* bit offset region in bitmap[index] */
1037 int nlongs_reg; /* num longs spanned by region in bitmap */
1038 int nbitsinlong; /* num bits of region in each spanned long */
1039 unsigned long mask; /* bitmask for one long of region */
1040 int i; /* scans bitmap by longs */
1041 int ret = 0; /* return value */
1042
1043 /*
1044 * Either nlongs_reg == 1 (for small orders that fit in one long)
1045 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1046 */
1047 nbits_reg = 1 << order;
1048 index = pos / BITS_PER_LONG;
1049 offset = pos - (index * BITS_PER_LONG);
1050 nlongs_reg = BITS_TO_LONGS(nbits_reg);
1051 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1052
1053 /*
1054 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1055 * overflows if nbitsinlong == BITS_PER_LONG.
1056 */
1057 mask = (1UL << (nbitsinlong - 1));
1058 mask += mask - 1;
1059 mask <<= offset;
1060
1061 switch (reg_op) {
1062 case REG_OP_ISFREE:
1063 for (i = 0; i < nlongs_reg; i++) {
1064 if (bitmap[index + i] & mask)
1065 goto done;
1066 }
1067 ret = 1; /* all bits in region free (zero) */
1068 break;
1069
1070 case REG_OP_ALLOC:
1071 for (i = 0; i < nlongs_reg; i++)
1072 bitmap[index + i] |= mask;
1073 break;
1074
1075 case REG_OP_RELEASE:
1076 for (i = 0; i < nlongs_reg; i++)
1077 bitmap[index + i] &= ~mask;
1078 break;
1079 }
1080 done:
1081 return ret;
1082 }
1083
1084 /**
1085 * bitmap_find_free_region - find a contiguous aligned mem region
1086 * @bitmap: array of unsigned longs corresponding to the bitmap
1087 * @bits: number of bits in the bitmap
1088 * @order: region size (log base 2 of number of bits) to find
1089 *
1090 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1091 * allocate them (set them to one). Only consider regions of length
1092 * a power (@order) of two, aligned to that power of two, which
1093 * makes the search algorithm much faster.
1094 *
1095 * Return the bit offset in bitmap of the allocated region,
1096 * or -errno on failure.
1097 */
1098 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
1099 {
1100 unsigned int pos, end; /* scans bitmap by regions of size order */
1101
1102 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
1103 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1104 continue;
1105 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1106 return pos;
1107 }
1108 return -ENOMEM;
1109 }
1110 EXPORT_SYMBOL(bitmap_find_free_region);
1111
1112 /**
1113 * bitmap_release_region - release allocated bitmap region
1114 * @bitmap: array of unsigned longs corresponding to the bitmap
1115 * @pos: beginning of bit region to release
1116 * @order: region size (log base 2 of number of bits) to release
1117 *
1118 * This is the complement to __bitmap_find_free_region() and releases
1119 * the found region (by clearing it in the bitmap).
1120 *
1121 * No return value.
1122 */
1123 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
1124 {
1125 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1126 }
1127 EXPORT_SYMBOL(bitmap_release_region);
1128
1129 /**
1130 * bitmap_allocate_region - allocate bitmap region
1131 * @bitmap: array of unsigned longs corresponding to the bitmap
1132 * @pos: beginning of bit region to allocate
1133 * @order: region size (log base 2 of number of bits) to allocate
1134 *
1135 * Allocate (set bits in) a specified region of a bitmap.
1136 *
1137 * Return 0 on success, or %-EBUSY if specified region wasn't
1138 * free (not all bits were zero).
1139 */
1140 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
1141 {
1142 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1143 return -EBUSY;
1144 return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1145 }
1146 EXPORT_SYMBOL(bitmap_allocate_region);
1147
1148 /**
1149 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1150 * @dst: destination buffer
1151 * @src: bitmap to copy
1152 * @nbits: number of bits in the bitmap
1153 *
1154 * Require nbits % BITS_PER_LONG == 0.
1155 */
1156 #ifdef __BIG_ENDIAN
1157 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
1158 {
1159 unsigned int i;
1160
1161 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1162 if (BITS_PER_LONG == 64)
1163 dst[i] = cpu_to_le64(src[i]);
1164 else
1165 dst[i] = cpu_to_le32(src[i]);
1166 }
1167 }
1168 EXPORT_SYMBOL(bitmap_copy_le);
1169 #endif
1170
1171 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
1172 {
1173 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
1174 flags);
1175 }
1176 EXPORT_SYMBOL(bitmap_alloc);
1177
1178 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
1179 {
1180 return bitmap_alloc(nbits, flags | __GFP_ZERO);
1181 }
1182 EXPORT_SYMBOL(bitmap_zalloc);
1183
1184 void bitmap_free(const unsigned long *bitmap)
1185 {
1186 kfree(bitmap);
1187 }
1188 EXPORT_SYMBOL(bitmap_free);
1189
1190 #if BITS_PER_LONG == 64
1191 /**
1192 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
1193 * @bitmap: array of unsigned longs, the destination bitmap
1194 * @buf: array of u32 (in host byte order), the source bitmap
1195 * @nbits: number of bits in @bitmap
1196 */
1197 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)
1198 {
1199 unsigned int i, halfwords;
1200
1201 halfwords = DIV_ROUND_UP(nbits, 32);
1202 for (i = 0; i < halfwords; i++) {
1203 bitmap[i/2] = (unsigned long) buf[i];
1204 if (++i < halfwords)
1205 bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
1206 }
1207
1208 /* Clear tail bits in last word beyond nbits. */
1209 if (nbits % BITS_PER_LONG)
1210 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
1211 }
1212 EXPORT_SYMBOL(bitmap_from_arr32);
1213
1214 /**
1215 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
1216 * @buf: array of u32 (in host byte order), the dest bitmap
1217 * @bitmap: array of unsigned longs, the source bitmap
1218 * @nbits: number of bits in @bitmap
1219 */
1220 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
1221 {
1222 unsigned int i, halfwords;
1223
1224 halfwords = DIV_ROUND_UP(nbits, 32);
1225 for (i = 0; i < halfwords; i++) {
1226 buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
1227 if (++i < halfwords)
1228 buf[i] = (u32) (bitmap[i/2] >> 32);
1229 }
1230
1231 /* Clear tail bits in last element of array beyond nbits. */
1232 if (nbits % BITS_PER_LONG)
1233 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
1234 }
1235 EXPORT_SYMBOL(bitmap_to_arr32);
1236
1237 #endif