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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 <linux/kernel.h>
16#include <linux/string.h>
17#include <linux/uaccess.h>
18
19#include <asm/page.h>
20
21/*
22 * bitmaps provide an array of bits, implemented using an an
23 * array of unsigned longs. The number of valid bits in a
24 * given bitmap does _not_ need to be an exact multiple of
25 * BITS_PER_LONG.
26 *
27 * The possible unused bits in the last, partially used word
28 * of a bitmap are 'don't care'. The implementation makes
29 * no particular effort to keep them zero. It ensures that
30 * their value will not affect the results of any operation.
31 * The bitmap operations that return Boolean (bitmap_empty,
32 * for example) or scalar (bitmap_weight, for example) results
33 * carefully filter out these unused bits from impacting their
34 * results.
35 *
36 * These operations actually hold to a slightly stronger rule:
37 * if you don't input any bitmaps to these ops that have some
38 * unused bits set, then they won't output any set unused bits
39 * in output bitmaps.
40 *
41 * The byte ordering of bitmaps is more natural on little
42 * endian architectures. See the big-endian headers
43 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
44 * for the best explanations of this ordering.
45 */
46
47int __bitmap_equal(const unsigned long *bitmap1,
48 const unsigned long *bitmap2, unsigned int bits)
49{
50 unsigned int k, lim = bits/BITS_PER_LONG;
51 for (k = 0; k < lim; ++k)
52 if (bitmap1[k] != bitmap2[k])
53 return 0;
54
55 if (bits % BITS_PER_LONG)
56 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
57 return 0;
58
59 return 1;
60}
61EXPORT_SYMBOL(__bitmap_equal);
62
63void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
64{
65 unsigned int k, lim = bits/BITS_PER_LONG;
66 for (k = 0; k < lim; ++k)
67 dst[k] = ~src[k];
68
69 if (bits % BITS_PER_LONG)
70 dst[k] = ~src[k];
71}
72EXPORT_SYMBOL(__bitmap_complement);
73
74/**
75 * __bitmap_shift_right - logical right shift of the bits in a bitmap
76 * @dst : destination bitmap
77 * @src : source bitmap
78 * @shift : shift by this many bits
79 * @nbits : bitmap size, in bits
80 *
81 * Shifting right (dividing) means moving bits in the MS -> LS bit
82 * direction. Zeros are fed into the vacated MS positions and the
83 * LS bits shifted off the bottom are lost.
84 */
85void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
86 unsigned shift, unsigned nbits)
87{
88 unsigned k, lim = BITS_TO_LONGS(nbits);
89 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
90 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
91 for (k = 0; off + k < lim; ++k) {
92 unsigned long upper, lower;
93
94 /*
95 * If shift is not word aligned, take lower rem bits of
96 * word above and make them the top rem bits of result.
97 */
98 if (!rem || off + k + 1 >= lim)
99 upper = 0;
100 else {
101 upper = src[off + k + 1];
102 if (off + k + 1 == lim - 1)
103 upper &= mask;
104 upper <<= (BITS_PER_LONG - rem);
105 }
106 lower = src[off + k];
107 if (off + k == lim - 1)
108 lower &= mask;
109 lower >>= rem;
110 dst[k] = lower | upper;
111 }
112 if (off)
113 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
114}
115EXPORT_SYMBOL(__bitmap_shift_right);
116
117
118/**
119 * __bitmap_shift_left - logical left shift of the bits in a bitmap
120 * @dst : destination bitmap
121 * @src : source bitmap
122 * @shift : shift by this many bits
123 * @nbits : bitmap size, in bits
124 *
125 * Shifting left (multiplying) means moving bits in the LS -> MS
126 * direction. Zeros are fed into the vacated LS bit positions
127 * and those MS bits shifted off the top are lost.
128 */
129
130void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
131 unsigned int shift, unsigned int nbits)
132{
133 int k;
134 unsigned int lim = BITS_TO_LONGS(nbits);
135 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
136 for (k = lim - off - 1; k >= 0; --k) {
137 unsigned long upper, lower;
138
139 /*
140 * If shift is not word aligned, take upper rem bits of
141 * word below and make them the bottom rem bits of result.
142 */
143 if (rem && k > 0)
144 lower = src[k - 1] >> (BITS_PER_LONG - rem);
145 else
146 lower = 0;
147 upper = src[k] << rem;
148 dst[k + off] = lower | upper;
149 }
150 if (off)
151 memset(dst, 0, off*sizeof(unsigned long));
152}
153EXPORT_SYMBOL(__bitmap_shift_left);
154
155int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
156 const unsigned long *bitmap2, unsigned int bits)
157{
158 unsigned int k;
159 unsigned int lim = bits/BITS_PER_LONG;
160 unsigned long result = 0;
161
162 for (k = 0; k < lim; k++)
163 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
164 if (bits % BITS_PER_LONG)
165 result |= (dst[k] = bitmap1[k] & bitmap2[k] &
166 BITMAP_LAST_WORD_MASK(bits));
167 return result != 0;
168}
169EXPORT_SYMBOL(__bitmap_and);
170
171void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
172 const unsigned long *bitmap2, unsigned int bits)
173{
174 unsigned int k;
175 unsigned int nr = BITS_TO_LONGS(bits);
176
177 for (k = 0; k < nr; k++)
178 dst[k] = bitmap1[k] | bitmap2[k];
179}
180EXPORT_SYMBOL(__bitmap_or);
181
182void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
183 const unsigned long *bitmap2, unsigned int bits)
184{
185 unsigned int k;
186 unsigned int nr = BITS_TO_LONGS(bits);
187
188 for (k = 0; k < nr; k++)
189 dst[k] = bitmap1[k] ^ bitmap2[k];
190}
191EXPORT_SYMBOL(__bitmap_xor);
192
193int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
194 const unsigned long *bitmap2, unsigned int bits)
195{
196 unsigned int k;
197 unsigned int lim = bits/BITS_PER_LONG;
198 unsigned long result = 0;
199
200 for (k = 0; k < lim; k++)
201 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
202 if (bits % BITS_PER_LONG)
203 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
204 BITMAP_LAST_WORD_MASK(bits));
205 return result != 0;
206}
207EXPORT_SYMBOL(__bitmap_andnot);
208
209int __bitmap_intersects(const unsigned long *bitmap1,
210 const unsigned long *bitmap2, unsigned int bits)
211{
212 unsigned int k, lim = bits/BITS_PER_LONG;
213 for (k = 0; k < lim; ++k)
214 if (bitmap1[k] & bitmap2[k])
215 return 1;
216
217 if (bits % BITS_PER_LONG)
218 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
219 return 1;
220 return 0;
221}
222EXPORT_SYMBOL(__bitmap_intersects);
223
224int __bitmap_subset(const unsigned long *bitmap1,
225 const unsigned long *bitmap2, unsigned int bits)
226{
227 unsigned int k, lim = bits/BITS_PER_LONG;
228 for (k = 0; k < lim; ++k)
229 if (bitmap1[k] & ~bitmap2[k])
230 return 0;
231
232 if (bits % BITS_PER_LONG)
233 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
234 return 0;
235 return 1;
236}
237EXPORT_SYMBOL(__bitmap_subset);
238
239int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
240{
241 unsigned int k, lim = bits/BITS_PER_LONG;
242 int w = 0;
243
244 for (k = 0; k < lim; k++)
245 w += hweight_long(bitmap[k]);
246
247 if (bits % BITS_PER_LONG)
248 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
249
250 return w;
251}
252EXPORT_SYMBOL(__bitmap_weight);
253
254void bitmap_set(unsigned long *map, unsigned int start, int len)
255{
256 unsigned long *p = map + BIT_WORD(start);
257 const unsigned int size = start + len;
258 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
259 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
260
261 while (len - bits_to_set >= 0) {
262 *p |= mask_to_set;
263 len -= bits_to_set;
264 bits_to_set = BITS_PER_LONG;
265 mask_to_set = ~0UL;
266 p++;
267 }
268 if (len) {
269 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
270 *p |= mask_to_set;
271 }
272}
273EXPORT_SYMBOL(bitmap_set);
274
275void bitmap_clear(unsigned long *map, unsigned int start, int len)
276{
277 unsigned long *p = map + BIT_WORD(start);
278 const unsigned int size = start + len;
279 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
280 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
281
282 while (len - bits_to_clear >= 0) {
283 *p &= ~mask_to_clear;
284 len -= bits_to_clear;
285 bits_to_clear = BITS_PER_LONG;
286 mask_to_clear = ~0UL;
287 p++;
288 }
289 if (len) {
290 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
291 *p &= ~mask_to_clear;
292 }
293}
294EXPORT_SYMBOL(bitmap_clear);
295
296/**
297 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
298 * @map: The address to base the search on
299 * @size: The bitmap size in bits
300 * @start: The bitnumber to start searching at
301 * @nr: The number of zeroed bits we're looking for
302 * @align_mask: Alignment mask for zero area
303 * @align_offset: Alignment offset for zero area.
304 *
305 * The @align_mask should be one less than a power of 2; the effect is that
306 * the bit offset of all zero areas this function finds plus @align_offset
307 * is multiple of that power of 2.
308 */
309unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
310 unsigned long size,
311 unsigned long start,
312 unsigned int nr,
313 unsigned long align_mask,
314 unsigned long align_offset)
315{
316 unsigned long index, end, i;
317again:
318 index = find_next_zero_bit(map, size, start);
319
320 /* Align allocation */
321 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
322
323 end = index + nr;
324 if (end > size)
325 return end;
326 i = find_next_bit(map, end, index);
327 if (i < end) {
328 start = i + 1;
329 goto again;
330 }
331 return index;
332}
333EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
334
335/*
336 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
337 * second version by Paul Jackson, third by Joe Korty.
338 */
339
340#define CHUNKSZ 32
341#define nbits_to_hold_value(val) fls(val)
342#define BASEDEC 10 /* fancier cpuset lists input in decimal */
343
344/**
345 * __bitmap_parse - convert an ASCII hex string into a bitmap.
346 * @buf: pointer to buffer containing string.
347 * @buflen: buffer size in bytes. If string is smaller than this
348 * then it must be terminated with a \0.
349 * @is_user: location of buffer, 0 indicates kernel space
350 * @maskp: pointer to bitmap array that will contain result.
351 * @nmaskbits: size of bitmap, in bits.
352 *
353 * Commas group hex digits into chunks. Each chunk defines exactly 32
354 * bits of the resultant bitmask. No chunk may specify a value larger
355 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
356 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
357 * characters and for grouping errors such as "1,,5", ",44", "," and "".
358 * Leading and trailing whitespace accepted, but not embedded whitespace.
359 */
360int __bitmap_parse(const char *buf, unsigned int buflen,
361 int is_user, unsigned long *maskp,
362 int nmaskbits)
363{
364 int c, old_c, totaldigits, ndigits, nchunks, nbits;
365 u32 chunk;
366 const char __user __force *ubuf = (const char __user __force *)buf;
367
368 bitmap_zero(maskp, nmaskbits);
369
370 nchunks = nbits = totaldigits = c = 0;
371 do {
372 chunk = 0;
373 ndigits = totaldigits;
374
375 /* Get the next chunk of the bitmap */
376 while (buflen) {
377 old_c = c;
378 if (is_user) {
379 if (__get_user(c, ubuf++))
380 return -EFAULT;
381 }
382 else
383 c = *buf++;
384 buflen--;
385 if (isspace(c))
386 continue;
387
388 /*
389 * If the last character was a space and the current
390 * character isn't '\0', we've got embedded whitespace.
391 * This is a no-no, so throw an error.
392 */
393 if (totaldigits && c && isspace(old_c))
394 return -EINVAL;
395
396 /* A '\0' or a ',' signal the end of the chunk */
397 if (c == '\0' || c == ',')
398 break;
399
400 if (!isxdigit(c))
401 return -EINVAL;
402
403 /*
404 * Make sure there are at least 4 free bits in 'chunk'.
405 * If not, this hexdigit will overflow 'chunk', so
406 * throw an error.
407 */
408 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
409 return -EOVERFLOW;
410
411 chunk = (chunk << 4) | hex_to_bin(c);
412 totaldigits++;
413 }
414 if (ndigits == totaldigits)
415 return -EINVAL;
416 if (nchunks == 0 && chunk == 0)
417 continue;
418
419 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
420 *maskp |= chunk;
421 nchunks++;
422 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
423 if (nbits > nmaskbits)
424 return -EOVERFLOW;
425 } while (buflen && c == ',');
426
427 return 0;
428}
429EXPORT_SYMBOL(__bitmap_parse);
430
431/**
432 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
433 *
434 * @ubuf: pointer to user buffer containing string.
435 * @ulen: buffer size in bytes. If string is smaller than this
436 * then it must be terminated with a \0.
437 * @maskp: pointer to bitmap array that will contain result.
438 * @nmaskbits: size of bitmap, in bits.
439 *
440 * Wrapper for __bitmap_parse(), providing it with user buffer.
441 *
442 * We cannot have this as an inline function in bitmap.h because it needs
443 * linux/uaccess.h to get the access_ok() declaration and this causes
444 * cyclic dependencies.
445 */
446int bitmap_parse_user(const char __user *ubuf,
447 unsigned int ulen, unsigned long *maskp,
448 int nmaskbits)
449{
450 if (!access_ok(VERIFY_READ, ubuf, ulen))
451 return -EFAULT;
452 return __bitmap_parse((const char __force *)ubuf,
453 ulen, 1, maskp, nmaskbits);
454
455}
456EXPORT_SYMBOL(bitmap_parse_user);
457
458/**
459 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
460 * @list: indicates whether the bitmap must be list
461 * @buf: page aligned buffer into which string is placed
462 * @maskp: pointer to bitmap to convert
463 * @nmaskbits: size of bitmap, in bits
464 *
465 * Output format is a comma-separated list of decimal numbers and
466 * ranges if list is specified or hex digits grouped into comma-separated
467 * sets of 8 digits/set. Returns the number of characters written to buf.
468 *
469 * It is assumed that @buf is a pointer into a PAGE_SIZE area and that
470 * sufficient storage remains at @buf to accommodate the
471 * bitmap_print_to_pagebuf() output.
472 */
473int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
474 int nmaskbits)
475{
476 ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf;
477 int n = 0;
478
479 if (len > 1)
480 n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
481 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
482 return n;
483}
484EXPORT_SYMBOL(bitmap_print_to_pagebuf);
485
486/**
487 * __bitmap_parselist - convert list format ASCII string to bitmap
488 * @buf: read nul-terminated user string from this buffer
489 * @buflen: buffer size in bytes. If string is smaller than this
490 * then it must be terminated with a \0.
491 * @is_user: location of buffer, 0 indicates kernel space
492 * @maskp: write resulting mask here
493 * @nmaskbits: number of bits in mask to be written
494 *
495 * Input format is a comma-separated list of decimal numbers and
496 * ranges. Consecutively set bits are shown as two hyphen-separated
497 * decimal numbers, the smallest and largest bit numbers set in
498 * the range.
499 * Optionally each range can be postfixed to denote that only parts of it
500 * should be set. The range will divided to groups of specific size.
501 * From each group will be used only defined amount of bits.
502 * Syntax: range:used_size/group_size
503 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
504 *
505 * Returns 0 on success, -errno on invalid input strings.
506 * Error values:
507 * %-EINVAL: second number in range smaller than first
508 * %-EINVAL: invalid character in string
509 * %-ERANGE: bit number specified too large for mask
510 */
511static int __bitmap_parselist(const char *buf, unsigned int buflen,
512 int is_user, unsigned long *maskp,
513 int nmaskbits)
514{
515 unsigned int a, b, old_a, old_b;
516 unsigned int group_size, used_size;
517 int c, old_c, totaldigits, ndigits;
518 const char __user __force *ubuf = (const char __user __force *)buf;
519 int at_start, in_range, in_partial_range;
520
521 totaldigits = c = 0;
522 old_a = old_b = 0;
523 group_size = used_size = 0;
524 bitmap_zero(maskp, nmaskbits);
525 do {
526 at_start = 1;
527 in_range = 0;
528 in_partial_range = 0;
529 a = b = 0;
530 ndigits = totaldigits;
531
532 /* Get the next cpu# or a range of cpu#'s */
533 while (buflen) {
534 old_c = c;
535 if (is_user) {
536 if (__get_user(c, ubuf++))
537 return -EFAULT;
538 } else
539 c = *buf++;
540 buflen--;
541 if (isspace(c))
542 continue;
543
544 /* A '\0' or a ',' signal the end of a cpu# or range */
545 if (c == '\0' || c == ',')
546 break;
547 /*
548 * whitespaces between digits are not allowed,
549 * but it's ok if whitespaces are on head or tail.
550 * when old_c is whilespace,
551 * if totaldigits == ndigits, whitespace is on head.
552 * if whitespace is on tail, it should not run here.
553 * as c was ',' or '\0',
554 * the last code line has broken the current loop.
555 */
556 if ((totaldigits != ndigits) && isspace(old_c))
557 return -EINVAL;
558
559 if (c == '/') {
560 used_size = a;
561 at_start = 1;
562 in_range = 0;
563 a = b = 0;
564 continue;
565 }
566
567 if (c == ':') {
568 old_a = a;
569 old_b = b;
570 at_start = 1;
571 in_range = 0;
572 in_partial_range = 1;
573 a = b = 0;
574 continue;
575 }
576
577 if (c == '-') {
578 if (at_start || in_range)
579 return -EINVAL;
580 b = 0;
581 in_range = 1;
582 at_start = 1;
583 continue;
584 }
585
586 if (!isdigit(c))
587 return -EINVAL;
588
589 b = b * 10 + (c - '0');
590 if (!in_range)
591 a = b;
592 at_start = 0;
593 totaldigits++;
594 }
595 if (ndigits == totaldigits)
596 continue;
597 if (in_partial_range) {
598 group_size = a;
599 a = old_a;
600 b = old_b;
601 old_a = old_b = 0;
602 }
603 /* if no digit is after '-', it's wrong*/
604 if (at_start && in_range)
605 return -EINVAL;
606 if (!(a <= b) || !(used_size <= group_size))
607 return -EINVAL;
608 if (b >= nmaskbits)
609 return -ERANGE;
610 while (a <= b) {
611 if (in_partial_range) {
612 static int pos_in_group = 1;
613
614 if (pos_in_group <= used_size)
615 set_bit(a, maskp);
616
617 if (a == b || ++pos_in_group > group_size)
618 pos_in_group = 1;
619 } else
620 set_bit(a, maskp);
621 a++;
622 }
623 } while (buflen && c == ',');
624 return 0;
625}
626
627int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
628{
629 char *nl = strchrnul(bp, '\n');
630 int len = nl - bp;
631
632 return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
633}
634EXPORT_SYMBOL(bitmap_parselist);
635
636
637/**
638 * bitmap_parselist_user()
639 *
640 * @ubuf: pointer to user buffer containing string.
641 * @ulen: buffer size in bytes. If string is smaller than this
642 * then it must be terminated with a \0.
643 * @maskp: pointer to bitmap array that will contain result.
644 * @nmaskbits: size of bitmap, in bits.
645 *
646 * Wrapper for bitmap_parselist(), providing it with user buffer.
647 *
648 * We cannot have this as an inline function in bitmap.h because it needs
649 * linux/uaccess.h to get the access_ok() declaration and this causes
650 * cyclic dependencies.
651 */
652int bitmap_parselist_user(const char __user *ubuf,
653 unsigned int ulen, unsigned long *maskp,
654 int nmaskbits)
655{
656 if (!access_ok(VERIFY_READ, ubuf, ulen))
657 return -EFAULT;
658 return __bitmap_parselist((const char __force *)ubuf,
659 ulen, 1, maskp, nmaskbits);
660}
661EXPORT_SYMBOL(bitmap_parselist_user);
662
663
664/**
665 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
666 * @buf: pointer to a bitmap
667 * @pos: a bit position in @buf (0 <= @pos < @nbits)
668 * @nbits: number of valid bit positions in @buf
669 *
670 * Map the bit at position @pos in @buf (of length @nbits) to the
671 * ordinal of which set bit it is. If it is not set or if @pos
672 * is not a valid bit position, map to -1.
673 *
674 * If for example, just bits 4 through 7 are set in @buf, then @pos
675 * values 4 through 7 will get mapped to 0 through 3, respectively,
676 * and other @pos values will get mapped to -1. When @pos value 7
677 * gets mapped to (returns) @ord value 3 in this example, that means
678 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
679 *
680 * The bit positions 0 through @bits are valid positions in @buf.
681 */
682static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
683{
684 if (pos >= nbits || !test_bit(pos, buf))
685 return -1;
686
687 return __bitmap_weight(buf, pos);
688}
689
690/**
691 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
692 * @buf: pointer to bitmap
693 * @ord: ordinal bit position (n-th set bit, n >= 0)
694 * @nbits: number of valid bit positions in @buf
695 *
696 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
697 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord
698 * >= weight(buf), returns @nbits.
699 *
700 * If for example, just bits 4 through 7 are set in @buf, then @ord
701 * values 0 through 3 will get mapped to 4 through 7, respectively,
702 * and all other @ord values returns @nbits. When @ord value 3
703 * gets mapped to (returns) @pos value 7 in this example, that means
704 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
705 *
706 * The bit positions 0 through @nbits-1 are valid positions in @buf.
707 */
708unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits)
709{
710 unsigned int pos;
711
712 for (pos = find_first_bit(buf, nbits);
713 pos < nbits && ord;
714 pos = find_next_bit(buf, nbits, pos + 1))
715 ord--;
716
717 return pos;
718}
719
720/**
721 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
722 * @dst: remapped result
723 * @src: subset to be remapped
724 * @old: defines domain of map
725 * @new: defines range of map
726 * @nbits: number of bits in each of these bitmaps
727 *
728 * Let @old and @new define a mapping of bit positions, such that
729 * whatever position is held by the n-th set bit in @old is mapped
730 * to the n-th set bit in @new. In the more general case, allowing
731 * for the possibility that the weight 'w' of @new is less than the
732 * weight of @old, map the position of the n-th set bit in @old to
733 * the position of the m-th set bit in @new, where m == n % w.
734 *
735 * If either of the @old and @new bitmaps are empty, or if @src and
736 * @dst point to the same location, then this routine copies @src
737 * to @dst.
738 *
739 * The positions of unset bits in @old are mapped to themselves
740 * (the identify map).
741 *
742 * Apply the above specified mapping to @src, placing the result in
743 * @dst, clearing any bits previously set in @dst.
744 *
745 * For example, lets say that @old has bits 4 through 7 set, and
746 * @new has bits 12 through 15 set. This defines the mapping of bit
747 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
748 * bit positions unchanged. So if say @src comes into this routine
749 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
750 * 13 and 15 set.
751 */
752void bitmap_remap(unsigned long *dst, const unsigned long *src,
753 const unsigned long *old, const unsigned long *new,
754 unsigned int nbits)
755{
756 unsigned int oldbit, w;
757
758 if (dst == src) /* following doesn't handle inplace remaps */
759 return;
760 bitmap_zero(dst, nbits);
761
762 w = bitmap_weight(new, nbits);
763 for_each_set_bit(oldbit, src, nbits) {
764 int n = bitmap_pos_to_ord(old, oldbit, nbits);
765
766 if (n < 0 || w == 0)
767 set_bit(oldbit, dst); /* identity map */
768 else
769 set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst);
770 }
771}
772EXPORT_SYMBOL(bitmap_remap);
773
774/**
775 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
776 * @oldbit: bit position to be mapped
777 * @old: defines domain of map
778 * @new: defines range of map
779 * @bits: number of bits in each of these bitmaps
780 *
781 * Let @old and @new define a mapping of bit positions, such that
782 * whatever position is held by the n-th set bit in @old is mapped
783 * to the n-th set bit in @new. In the more general case, allowing
784 * for the possibility that the weight 'w' of @new is less than the
785 * weight of @old, map the position of the n-th set bit in @old to
786 * the position of the m-th set bit in @new, where m == n % w.
787 *
788 * The positions of unset bits in @old are mapped to themselves
789 * (the identify map).
790 *
791 * Apply the above specified mapping to bit position @oldbit, returning
792 * the new bit position.
793 *
794 * For example, lets say that @old has bits 4 through 7 set, and
795 * @new has bits 12 through 15 set. This defines the mapping of bit
796 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
797 * bit positions unchanged. So if say @oldbit is 5, then this routine
798 * returns 13.
799 */
800int bitmap_bitremap(int oldbit, const unsigned long *old,
801 const unsigned long *new, int bits)
802{
803 int w = bitmap_weight(new, bits);
804 int n = bitmap_pos_to_ord(old, oldbit, bits);
805 if (n < 0 || w == 0)
806 return oldbit;
807 else
808 return bitmap_ord_to_pos(new, n % w, bits);
809}
810EXPORT_SYMBOL(bitmap_bitremap);
811
812/**
813 * bitmap_onto - translate one bitmap relative to another
814 * @dst: resulting translated bitmap
815 * @orig: original untranslated bitmap
816 * @relmap: bitmap relative to which translated
817 * @bits: number of bits in each of these bitmaps
818 *
819 * Set the n-th bit of @dst iff there exists some m such that the
820 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
821 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
822 * (If you understood the previous sentence the first time your
823 * read it, you're overqualified for your current job.)
824 *
825 * In other words, @orig is mapped onto (surjectively) @dst,
826 * using the map { <n, m> | the n-th bit of @relmap is the
827 * m-th set bit of @relmap }.
828 *
829 * Any set bits in @orig above bit number W, where W is the
830 * weight of (number of set bits in) @relmap are mapped nowhere.
831 * In particular, if for all bits m set in @orig, m >= W, then
832 * @dst will end up empty. In situations where the possibility
833 * of such an empty result is not desired, one way to avoid it is
834 * to use the bitmap_fold() operator, below, to first fold the
835 * @orig bitmap over itself so that all its set bits x are in the
836 * range 0 <= x < W. The bitmap_fold() operator does this by
837 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
838 *
839 * Example [1] for bitmap_onto():
840 * Let's say @relmap has bits 30-39 set, and @orig has bits
841 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
842 * @dst will have bits 31, 33, 35, 37 and 39 set.
843 *
844 * When bit 0 is set in @orig, it means turn on the bit in
845 * @dst corresponding to whatever is the first bit (if any)
846 * that is turned on in @relmap. Since bit 0 was off in the
847 * above example, we leave off that bit (bit 30) in @dst.
848 *
849 * When bit 1 is set in @orig (as in the above example), it
850 * means turn on the bit in @dst corresponding to whatever
851 * is the second bit that is turned on in @relmap. The second
852 * bit in @relmap that was turned on in the above example was
853 * bit 31, so we turned on bit 31 in @dst.
854 *
855 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
856 * because they were the 4th, 6th, 8th and 10th set bits
857 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
858 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
859 *
860 * When bit 11 is set in @orig, it means turn on the bit in
861 * @dst corresponding to whatever is the twelfth bit that is
862 * turned on in @relmap. In the above example, there were
863 * only ten bits turned on in @relmap (30..39), so that bit
864 * 11 was set in @orig had no affect on @dst.
865 *
866 * Example [2] for bitmap_fold() + bitmap_onto():
867 * Let's say @relmap has these ten bits set:
868 * 40 41 42 43 45 48 53 61 74 95
869 * (for the curious, that's 40 plus the first ten terms of the
870 * Fibonacci sequence.)
871 *
872 * Further lets say we use the following code, invoking
873 * bitmap_fold() then bitmap_onto, as suggested above to
874 * avoid the possibility of an empty @dst result:
875 *
876 * unsigned long *tmp; // a temporary bitmap's bits
877 *
878 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
879 * bitmap_onto(dst, tmp, relmap, bits);
880 *
881 * Then this table shows what various values of @dst would be, for
882 * various @orig's. I list the zero-based positions of each set bit.
883 * The tmp column shows the intermediate result, as computed by
884 * using bitmap_fold() to fold the @orig bitmap modulo ten
885 * (the weight of @relmap).
886 *
887 * @orig tmp @dst
888 * 0 0 40
889 * 1 1 41
890 * 9 9 95
891 * 10 0 40 (*)
892 * 1 3 5 7 1 3 5 7 41 43 48 61
893 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
894 * 0 9 18 27 0 9 8 7 40 61 74 95
895 * 0 10 20 30 0 40
896 * 0 11 22 33 0 1 2 3 40 41 42 43
897 * 0 12 24 36 0 2 4 6 40 42 45 53
898 * 78 102 211 1 2 8 41 42 74 (*)
899 *
900 * (*) For these marked lines, if we hadn't first done bitmap_fold()
901 * into tmp, then the @dst result would have been empty.
902 *
903 * If either of @orig or @relmap is empty (no set bits), then @dst
904 * will be returned empty.
905 *
906 * If (as explained above) the only set bits in @orig are in positions
907 * m where m >= W, (where W is the weight of @relmap) then @dst will
908 * once again be returned empty.
909 *
910 * All bits in @dst not set by the above rule are cleared.
911 */
912void bitmap_onto(unsigned long *dst, const unsigned long *orig,
913 const unsigned long *relmap, unsigned int bits)
914{
915 unsigned int n, m; /* same meaning as in above comment */
916
917 if (dst == orig) /* following doesn't handle inplace mappings */
918 return;
919 bitmap_zero(dst, bits);
920
921 /*
922 * The following code is a more efficient, but less
923 * obvious, equivalent to the loop:
924 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
925 * n = bitmap_ord_to_pos(orig, m, bits);
926 * if (test_bit(m, orig))
927 * set_bit(n, dst);
928 * }
929 */
930
931 m = 0;
932 for_each_set_bit(n, relmap, bits) {
933 /* m == bitmap_pos_to_ord(relmap, n, bits) */
934 if (test_bit(m, orig))
935 set_bit(n, dst);
936 m++;
937 }
938}
939EXPORT_SYMBOL(bitmap_onto);
940
941/**
942 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
943 * @dst: resulting smaller bitmap
944 * @orig: original larger bitmap
945 * @sz: specified size
946 * @nbits: number of bits in each of these bitmaps
947 *
948 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
949 * Clear all other bits in @dst. See further the comment and
950 * Example [2] for bitmap_onto() for why and how to use this.
951 */
952void bitmap_fold(unsigned long *dst, const unsigned long *orig,
953 unsigned int sz, unsigned int nbits)
954{
955 unsigned int oldbit;
956
957 if (dst == orig) /* following doesn't handle inplace mappings */
958 return;
959 bitmap_zero(dst, nbits);
960
961 for_each_set_bit(oldbit, orig, nbits)
962 set_bit(oldbit % sz, dst);
963}
964EXPORT_SYMBOL(bitmap_fold);
965
966/*
967 * Common code for bitmap_*_region() routines.
968 * bitmap: array of unsigned longs corresponding to the bitmap
969 * pos: the beginning of the region
970 * order: region size (log base 2 of number of bits)
971 * reg_op: operation(s) to perform on that region of bitmap
972 *
973 * Can set, verify and/or release a region of bits in a bitmap,
974 * depending on which combination of REG_OP_* flag bits is set.
975 *
976 * A region of a bitmap is a sequence of bits in the bitmap, of
977 * some size '1 << order' (a power of two), aligned to that same
978 * '1 << order' power of two.
979 *
980 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
981 * Returns 0 in all other cases and reg_ops.
982 */
983
984enum {
985 REG_OP_ISFREE, /* true if region is all zero bits */
986 REG_OP_ALLOC, /* set all bits in region */
987 REG_OP_RELEASE, /* clear all bits in region */
988};
989
990static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
991{
992 int nbits_reg; /* number of bits in region */
993 int index; /* index first long of region in bitmap */
994 int offset; /* bit offset region in bitmap[index] */
995 int nlongs_reg; /* num longs spanned by region in bitmap */
996 int nbitsinlong; /* num bits of region in each spanned long */
997 unsigned long mask; /* bitmask for one long of region */
998 int i; /* scans bitmap by longs */
999 int ret = 0; /* return value */
1000
1001 /*
1002 * Either nlongs_reg == 1 (for small orders that fit in one long)
1003 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1004 */
1005 nbits_reg = 1 << order;
1006 index = pos / BITS_PER_LONG;
1007 offset = pos - (index * BITS_PER_LONG);
1008 nlongs_reg = BITS_TO_LONGS(nbits_reg);
1009 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1010
1011 /*
1012 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1013 * overflows if nbitsinlong == BITS_PER_LONG.
1014 */
1015 mask = (1UL << (nbitsinlong - 1));
1016 mask += mask - 1;
1017 mask <<= offset;
1018
1019 switch (reg_op) {
1020 case REG_OP_ISFREE:
1021 for (i = 0; i < nlongs_reg; i++) {
1022 if (bitmap[index + i] & mask)
1023 goto done;
1024 }
1025 ret = 1; /* all bits in region free (zero) */
1026 break;
1027
1028 case REG_OP_ALLOC:
1029 for (i = 0; i < nlongs_reg; i++)
1030 bitmap[index + i] |= mask;
1031 break;
1032
1033 case REG_OP_RELEASE:
1034 for (i = 0; i < nlongs_reg; i++)
1035 bitmap[index + i] &= ~mask;
1036 break;
1037 }
1038done:
1039 return ret;
1040}
1041
1042/**
1043 * bitmap_find_free_region - find a contiguous aligned mem region
1044 * @bitmap: array of unsigned longs corresponding to the bitmap
1045 * @bits: number of bits in the bitmap
1046 * @order: region size (log base 2 of number of bits) to find
1047 *
1048 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1049 * allocate them (set them to one). Only consider regions of length
1050 * a power (@order) of two, aligned to that power of two, which
1051 * makes the search algorithm much faster.
1052 *
1053 * Return the bit offset in bitmap of the allocated region,
1054 * or -errno on failure.
1055 */
1056int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
1057{
1058 unsigned int pos, end; /* scans bitmap by regions of size order */
1059
1060 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
1061 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1062 continue;
1063 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1064 return pos;
1065 }
1066 return -ENOMEM;
1067}
1068EXPORT_SYMBOL(bitmap_find_free_region);
1069
1070/**
1071 * bitmap_release_region - release allocated bitmap region
1072 * @bitmap: array of unsigned longs corresponding to the bitmap
1073 * @pos: beginning of bit region to release
1074 * @order: region size (log base 2 of number of bits) to release
1075 *
1076 * This is the complement to __bitmap_find_free_region() and releases
1077 * the found region (by clearing it in the bitmap).
1078 *
1079 * No return value.
1080 */
1081void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
1082{
1083 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1084}
1085EXPORT_SYMBOL(bitmap_release_region);
1086
1087/**
1088 * bitmap_allocate_region - allocate bitmap region
1089 * @bitmap: array of unsigned longs corresponding to the bitmap
1090 * @pos: beginning of bit region to allocate
1091 * @order: region size (log base 2 of number of bits) to allocate
1092 *
1093 * Allocate (set bits in) a specified region of a bitmap.
1094 *
1095 * Return 0 on success, or %-EBUSY if specified region wasn't
1096 * free (not all bits were zero).
1097 */
1098int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
1099{
1100 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1101 return -EBUSY;
1102 return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1103}
1104EXPORT_SYMBOL(bitmap_allocate_region);
1105
1106/**
1107 * bitmap_from_u32array - copy the contents of a u32 array of bits to bitmap
1108 * @bitmap: array of unsigned longs, the destination bitmap, non NULL
1109 * @nbits: number of bits in @bitmap
1110 * @buf: array of u32 (in host byte order), the source bitmap, non NULL
1111 * @nwords: number of u32 words in @buf
1112 *
1113 * copy min(nbits, 32*nwords) bits from @buf to @bitmap, remaining
1114 * bits between nword and nbits in @bitmap (if any) are cleared. In
1115 * last word of @bitmap, the bits beyond nbits (if any) are kept
1116 * unchanged.
1117 *
1118 * Return the number of bits effectively copied.
1119 */
1120unsigned int
1121bitmap_from_u32array(unsigned long *bitmap, unsigned int nbits,
1122 const u32 *buf, unsigned int nwords)
1123{
1124 unsigned int dst_idx, src_idx;
1125
1126 for (src_idx = dst_idx = 0; dst_idx < BITS_TO_LONGS(nbits); ++dst_idx) {
1127 unsigned long part = 0;
1128
1129 if (src_idx < nwords)
1130 part = buf[src_idx++];
1131
1132#if BITS_PER_LONG == 64
1133 if (src_idx < nwords)
1134 part |= ((unsigned long) buf[src_idx++]) << 32;
1135#endif
1136
1137 if (dst_idx < nbits/BITS_PER_LONG)
1138 bitmap[dst_idx] = part;
1139 else {
1140 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
1141
1142 bitmap[dst_idx] = (bitmap[dst_idx] & ~mask)
1143 | (part & mask);
1144 }
1145 }
1146
1147 return min_t(unsigned int, nbits, 32*nwords);
1148}
1149EXPORT_SYMBOL(bitmap_from_u32array);
1150
1151/**
1152 * bitmap_to_u32array - copy the contents of bitmap to a u32 array of bits
1153 * @buf: array of u32 (in host byte order), the dest bitmap, non NULL
1154 * @nwords: number of u32 words in @buf
1155 * @bitmap: array of unsigned longs, the source bitmap, non NULL
1156 * @nbits: number of bits in @bitmap
1157 *
1158 * copy min(nbits, 32*nwords) bits from @bitmap to @buf. Remaining
1159 * bits after nbits in @buf (if any) are cleared.
1160 *
1161 * Return the number of bits effectively copied.
1162 */
1163unsigned int
1164bitmap_to_u32array(u32 *buf, unsigned int nwords,
1165 const unsigned long *bitmap, unsigned int nbits)
1166{
1167 unsigned int dst_idx = 0, src_idx = 0;
1168
1169 while (dst_idx < nwords) {
1170 unsigned long part = 0;
1171
1172 if (src_idx < BITS_TO_LONGS(nbits)) {
1173 part = bitmap[src_idx];
1174 if (src_idx >= nbits/BITS_PER_LONG)
1175 part &= BITMAP_LAST_WORD_MASK(nbits);
1176 src_idx++;
1177 }
1178
1179 buf[dst_idx++] = part & 0xffffffffUL;
1180
1181#if BITS_PER_LONG == 64
1182 if (dst_idx < nwords) {
1183 part >>= 32;
1184 buf[dst_idx++] = part & 0xffffffffUL;
1185 }
1186#endif
1187 }
1188
1189 return min_t(unsigned int, nbits, 32*nwords);
1190}
1191EXPORT_SYMBOL(bitmap_to_u32array);
1192
1193/**
1194 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1195 * @dst: destination buffer
1196 * @src: bitmap to copy
1197 * @nbits: number of bits in the bitmap
1198 *
1199 * Require nbits % BITS_PER_LONG == 0.
1200 */
1201#ifdef __BIG_ENDIAN
1202void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
1203{
1204 unsigned int i;
1205
1206 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1207 if (BITS_PER_LONG == 64)
1208 dst[i] = cpu_to_le64(src[i]);
1209 else
1210 dst[i] = cpu_to_le32(src[i]);
1211 }
1212}
1213EXPORT_SYMBOL(bitmap_copy_le);
1214#endif
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/module.h>
9#include <linux/ctype.h>
10#include <linux/errno.h>
11#include <linux/bitmap.h>
12#include <linux/bitops.h>
13#include <asm/uaccess.h>
14
15/*
16 * bitmaps provide an array of bits, implemented using an an
17 * array of unsigned longs. The number of valid bits in a
18 * given bitmap does _not_ need to be an exact multiple of
19 * BITS_PER_LONG.
20 *
21 * The possible unused bits in the last, partially used word
22 * of a bitmap are 'don't care'. The implementation makes
23 * no particular effort to keep them zero. It ensures that
24 * their value will not affect the results of any operation.
25 * The bitmap operations that return Boolean (bitmap_empty,
26 * for example) or scalar (bitmap_weight, for example) results
27 * carefully filter out these unused bits from impacting their
28 * results.
29 *
30 * These operations actually hold to a slightly stronger rule:
31 * if you don't input any bitmaps to these ops that have some
32 * unused bits set, then they won't output any set unused bits
33 * in output bitmaps.
34 *
35 * The byte ordering of bitmaps is more natural on little
36 * endian architectures. See the big-endian headers
37 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
38 * for the best explanations of this ordering.
39 */
40
41int __bitmap_empty(const unsigned long *bitmap, int bits)
42{
43 int k, lim = bits/BITS_PER_LONG;
44 for (k = 0; k < lim; ++k)
45 if (bitmap[k])
46 return 0;
47
48 if (bits % BITS_PER_LONG)
49 if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
50 return 0;
51
52 return 1;
53}
54EXPORT_SYMBOL(__bitmap_empty);
55
56int __bitmap_full(const unsigned long *bitmap, int bits)
57{
58 int k, lim = bits/BITS_PER_LONG;
59 for (k = 0; k < lim; ++k)
60 if (~bitmap[k])
61 return 0;
62
63 if (bits % BITS_PER_LONG)
64 if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
65 return 0;
66
67 return 1;
68}
69EXPORT_SYMBOL(__bitmap_full);
70
71int __bitmap_equal(const unsigned long *bitmap1,
72 const unsigned long *bitmap2, int bits)
73{
74 int k, lim = bits/BITS_PER_LONG;
75 for (k = 0; k < lim; ++k)
76 if (bitmap1[k] != bitmap2[k])
77 return 0;
78
79 if (bits % BITS_PER_LONG)
80 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
81 return 0;
82
83 return 1;
84}
85EXPORT_SYMBOL(__bitmap_equal);
86
87void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
88{
89 int k, lim = bits/BITS_PER_LONG;
90 for (k = 0; k < lim; ++k)
91 dst[k] = ~src[k];
92
93 if (bits % BITS_PER_LONG)
94 dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
95}
96EXPORT_SYMBOL(__bitmap_complement);
97
98/**
99 * __bitmap_shift_right - logical right shift of the bits in a bitmap
100 * @dst : destination bitmap
101 * @src : source bitmap
102 * @shift : shift by this many bits
103 * @bits : bitmap size, in bits
104 *
105 * Shifting right (dividing) means moving bits in the MS -> LS bit
106 * direction. Zeros are fed into the vacated MS positions and the
107 * LS bits shifted off the bottom are lost.
108 */
109void __bitmap_shift_right(unsigned long *dst,
110 const unsigned long *src, int shift, int bits)
111{
112 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
113 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
114 unsigned long mask = (1UL << left) - 1;
115 for (k = 0; off + k < lim; ++k) {
116 unsigned long upper, lower;
117
118 /*
119 * If shift is not word aligned, take lower rem bits of
120 * word above and make them the top rem bits of result.
121 */
122 if (!rem || off + k + 1 >= lim)
123 upper = 0;
124 else {
125 upper = src[off + k + 1];
126 if (off + k + 1 == lim - 1 && left)
127 upper &= mask;
128 }
129 lower = src[off + k];
130 if (left && off + k == lim - 1)
131 lower &= mask;
132 dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
133 if (left && k == lim - 1)
134 dst[k] &= mask;
135 }
136 if (off)
137 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
138}
139EXPORT_SYMBOL(__bitmap_shift_right);
140
141
142/**
143 * __bitmap_shift_left - logical left shift of the bits in a bitmap
144 * @dst : destination bitmap
145 * @src : source bitmap
146 * @shift : shift by this many bits
147 * @bits : bitmap size, in bits
148 *
149 * Shifting left (multiplying) means moving bits in the LS -> MS
150 * direction. Zeros are fed into the vacated LS bit positions
151 * and those MS bits shifted off the top are lost.
152 */
153
154void __bitmap_shift_left(unsigned long *dst,
155 const unsigned long *src, int shift, int bits)
156{
157 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
158 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
159 for (k = lim - off - 1; k >= 0; --k) {
160 unsigned long upper, lower;
161
162 /*
163 * If shift is not word aligned, take upper rem bits of
164 * word below and make them the bottom rem bits of result.
165 */
166 if (rem && k > 0)
167 lower = src[k - 1];
168 else
169 lower = 0;
170 upper = src[k];
171 if (left && k == lim - 1)
172 upper &= (1UL << left) - 1;
173 dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
174 if (left && k + off == lim - 1)
175 dst[k + off] &= (1UL << left) - 1;
176 }
177 if (off)
178 memset(dst, 0, off*sizeof(unsigned long));
179}
180EXPORT_SYMBOL(__bitmap_shift_left);
181
182int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
183 const unsigned long *bitmap2, int bits)
184{
185 int k;
186 int nr = BITS_TO_LONGS(bits);
187 unsigned long result = 0;
188
189 for (k = 0; k < nr; k++)
190 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
191 return result != 0;
192}
193EXPORT_SYMBOL(__bitmap_and);
194
195void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
196 const unsigned long *bitmap2, int bits)
197{
198 int k;
199 int nr = BITS_TO_LONGS(bits);
200
201 for (k = 0; k < nr; k++)
202 dst[k] = bitmap1[k] | bitmap2[k];
203}
204EXPORT_SYMBOL(__bitmap_or);
205
206void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
207 const unsigned long *bitmap2, int bits)
208{
209 int k;
210 int nr = BITS_TO_LONGS(bits);
211
212 for (k = 0; k < nr; k++)
213 dst[k] = bitmap1[k] ^ bitmap2[k];
214}
215EXPORT_SYMBOL(__bitmap_xor);
216
217int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
218 const unsigned long *bitmap2, int bits)
219{
220 int k;
221 int nr = BITS_TO_LONGS(bits);
222 unsigned long result = 0;
223
224 for (k = 0; k < nr; k++)
225 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
226 return result != 0;
227}
228EXPORT_SYMBOL(__bitmap_andnot);
229
230int __bitmap_intersects(const unsigned long *bitmap1,
231 const unsigned long *bitmap2, int bits)
232{
233 int k, lim = bits/BITS_PER_LONG;
234 for (k = 0; k < lim; ++k)
235 if (bitmap1[k] & bitmap2[k])
236 return 1;
237
238 if (bits % BITS_PER_LONG)
239 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
240 return 1;
241 return 0;
242}
243EXPORT_SYMBOL(__bitmap_intersects);
244
245int __bitmap_subset(const unsigned long *bitmap1,
246 const unsigned long *bitmap2, int bits)
247{
248 int k, lim = bits/BITS_PER_LONG;
249 for (k = 0; k < lim; ++k)
250 if (bitmap1[k] & ~bitmap2[k])
251 return 0;
252
253 if (bits % BITS_PER_LONG)
254 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
255 return 0;
256 return 1;
257}
258EXPORT_SYMBOL(__bitmap_subset);
259
260int __bitmap_weight(const unsigned long *bitmap, int bits)
261{
262 int k, w = 0, lim = bits/BITS_PER_LONG;
263
264 for (k = 0; k < lim; k++)
265 w += hweight_long(bitmap[k]);
266
267 if (bits % BITS_PER_LONG)
268 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
269
270 return w;
271}
272EXPORT_SYMBOL(__bitmap_weight);
273
274void bitmap_set(unsigned long *map, int start, int nr)
275{
276 unsigned long *p = map + BIT_WORD(start);
277 const int size = start + nr;
278 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
279 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
280
281 while (nr - bits_to_set >= 0) {
282 *p |= mask_to_set;
283 nr -= bits_to_set;
284 bits_to_set = BITS_PER_LONG;
285 mask_to_set = ~0UL;
286 p++;
287 }
288 if (nr) {
289 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
290 *p |= mask_to_set;
291 }
292}
293EXPORT_SYMBOL(bitmap_set);
294
295void bitmap_clear(unsigned long *map, int start, int nr)
296{
297 unsigned long *p = map + BIT_WORD(start);
298 const int size = start + nr;
299 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
300 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
301
302 while (nr - bits_to_clear >= 0) {
303 *p &= ~mask_to_clear;
304 nr -= bits_to_clear;
305 bits_to_clear = BITS_PER_LONG;
306 mask_to_clear = ~0UL;
307 p++;
308 }
309 if (nr) {
310 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
311 *p &= ~mask_to_clear;
312 }
313}
314EXPORT_SYMBOL(bitmap_clear);
315
316/*
317 * bitmap_find_next_zero_area - find a contiguous aligned zero area
318 * @map: The address to base the search on
319 * @size: The bitmap size in bits
320 * @start: The bitnumber to start searching at
321 * @nr: The number of zeroed bits we're looking for
322 * @align_mask: Alignment mask for zero area
323 *
324 * The @align_mask should be one less than a power of 2; the effect is that
325 * the bit offset of all zero areas this function finds is multiples of that
326 * power of 2. A @align_mask of 0 means no alignment is required.
327 */
328unsigned long bitmap_find_next_zero_area(unsigned long *map,
329 unsigned long size,
330 unsigned long start,
331 unsigned int nr,
332 unsigned long align_mask)
333{
334 unsigned long index, end, i;
335again:
336 index = find_next_zero_bit(map, size, start);
337
338 /* Align allocation */
339 index = __ALIGN_MASK(index, align_mask);
340
341 end = index + nr;
342 if (end > size)
343 return end;
344 i = find_next_bit(map, end, index);
345 if (i < end) {
346 start = i + 1;
347 goto again;
348 }
349 return index;
350}
351EXPORT_SYMBOL(bitmap_find_next_zero_area);
352
353/*
354 * Bitmap printing & parsing functions: first version by Bill Irwin,
355 * second version by Paul Jackson, third by Joe Korty.
356 */
357
358#define CHUNKSZ 32
359#define nbits_to_hold_value(val) fls(val)
360#define BASEDEC 10 /* fancier cpuset lists input in decimal */
361
362/**
363 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
364 * @buf: byte buffer into which string is placed
365 * @buflen: reserved size of @buf, in bytes
366 * @maskp: pointer to bitmap to convert
367 * @nmaskbits: size of bitmap, in bits
368 *
369 * Exactly @nmaskbits bits are displayed. Hex digits are grouped into
370 * comma-separated sets of eight digits per set.
371 */
372int bitmap_scnprintf(char *buf, unsigned int buflen,
373 const unsigned long *maskp, int nmaskbits)
374{
375 int i, word, bit, len = 0;
376 unsigned long val;
377 const char *sep = "";
378 int chunksz;
379 u32 chunkmask;
380
381 chunksz = nmaskbits & (CHUNKSZ - 1);
382 if (chunksz == 0)
383 chunksz = CHUNKSZ;
384
385 i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
386 for (; i >= 0; i -= CHUNKSZ) {
387 chunkmask = ((1ULL << chunksz) - 1);
388 word = i / BITS_PER_LONG;
389 bit = i % BITS_PER_LONG;
390 val = (maskp[word] >> bit) & chunkmask;
391 len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
392 (chunksz+3)/4, val);
393 chunksz = CHUNKSZ;
394 sep = ",";
395 }
396 return len;
397}
398EXPORT_SYMBOL(bitmap_scnprintf);
399
400/**
401 * __bitmap_parse - convert an ASCII hex string into a bitmap.
402 * @buf: pointer to buffer containing string.
403 * @buflen: buffer size in bytes. If string is smaller than this
404 * then it must be terminated with a \0.
405 * @is_user: location of buffer, 0 indicates kernel space
406 * @maskp: pointer to bitmap array that will contain result.
407 * @nmaskbits: size of bitmap, in bits.
408 *
409 * Commas group hex digits into chunks. Each chunk defines exactly 32
410 * bits of the resultant bitmask. No chunk may specify a value larger
411 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
412 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
413 * characters and for grouping errors such as "1,,5", ",44", "," and "".
414 * Leading and trailing whitespace accepted, but not embedded whitespace.
415 */
416int __bitmap_parse(const char *buf, unsigned int buflen,
417 int is_user, unsigned long *maskp,
418 int nmaskbits)
419{
420 int c, old_c, totaldigits, ndigits, nchunks, nbits;
421 u32 chunk;
422 const char __user *ubuf = buf;
423
424 bitmap_zero(maskp, nmaskbits);
425
426 nchunks = nbits = totaldigits = c = 0;
427 do {
428 chunk = ndigits = 0;
429
430 /* Get the next chunk of the bitmap */
431 while (buflen) {
432 old_c = c;
433 if (is_user) {
434 if (__get_user(c, ubuf++))
435 return -EFAULT;
436 }
437 else
438 c = *buf++;
439 buflen--;
440 if (isspace(c))
441 continue;
442
443 /*
444 * If the last character was a space and the current
445 * character isn't '\0', we've got embedded whitespace.
446 * This is a no-no, so throw an error.
447 */
448 if (totaldigits && c && isspace(old_c))
449 return -EINVAL;
450
451 /* A '\0' or a ',' signal the end of the chunk */
452 if (c == '\0' || c == ',')
453 break;
454
455 if (!isxdigit(c))
456 return -EINVAL;
457
458 /*
459 * Make sure there are at least 4 free bits in 'chunk'.
460 * If not, this hexdigit will overflow 'chunk', so
461 * throw an error.
462 */
463 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
464 return -EOVERFLOW;
465
466 chunk = (chunk << 4) | hex_to_bin(c);
467 ndigits++; totaldigits++;
468 }
469 if (ndigits == 0)
470 return -EINVAL;
471 if (nchunks == 0 && chunk == 0)
472 continue;
473
474 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
475 *maskp |= chunk;
476 nchunks++;
477 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
478 if (nbits > nmaskbits)
479 return -EOVERFLOW;
480 } while (buflen && c == ',');
481
482 return 0;
483}
484EXPORT_SYMBOL(__bitmap_parse);
485
486/**
487 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
488 *
489 * @ubuf: pointer to user buffer containing string.
490 * @ulen: buffer size in bytes. If string is smaller than this
491 * then it must be terminated with a \0.
492 * @maskp: pointer to bitmap array that will contain result.
493 * @nmaskbits: size of bitmap, in bits.
494 *
495 * Wrapper for __bitmap_parse(), providing it with user buffer.
496 *
497 * We cannot have this as an inline function in bitmap.h because it needs
498 * linux/uaccess.h to get the access_ok() declaration and this causes
499 * cyclic dependencies.
500 */
501int bitmap_parse_user(const char __user *ubuf,
502 unsigned int ulen, unsigned long *maskp,
503 int nmaskbits)
504{
505 if (!access_ok(VERIFY_READ, ubuf, ulen))
506 return -EFAULT;
507 return __bitmap_parse((const char *)ubuf, ulen, 1, maskp, nmaskbits);
508}
509EXPORT_SYMBOL(bitmap_parse_user);
510
511/*
512 * bscnl_emit(buf, buflen, rbot, rtop, bp)
513 *
514 * Helper routine for bitmap_scnlistprintf(). Write decimal number
515 * or range to buf, suppressing output past buf+buflen, with optional
516 * comma-prefix. Return len of what would be written to buf, if it
517 * all fit.
518 */
519static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
520{
521 if (len > 0)
522 len += scnprintf(buf + len, buflen - len, ",");
523 if (rbot == rtop)
524 len += scnprintf(buf + len, buflen - len, "%d", rbot);
525 else
526 len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
527 return len;
528}
529
530/**
531 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
532 * @buf: byte buffer into which string is placed
533 * @buflen: reserved size of @buf, in bytes
534 * @maskp: pointer to bitmap to convert
535 * @nmaskbits: size of bitmap, in bits
536 *
537 * Output format is a comma-separated list of decimal numbers and
538 * ranges. Consecutively set bits are shown as two hyphen-separated
539 * decimal numbers, the smallest and largest bit numbers set in
540 * the range. Output format is compatible with the format
541 * accepted as input by bitmap_parselist().
542 *
543 * The return value is the number of characters which would be
544 * generated for the given input, excluding the trailing '\0', as
545 * per ISO C99.
546 */
547int bitmap_scnlistprintf(char *buf, unsigned int buflen,
548 const unsigned long *maskp, int nmaskbits)
549{
550 int len = 0;
551 /* current bit is 'cur', most recently seen range is [rbot, rtop] */
552 int cur, rbot, rtop;
553
554 if (buflen == 0)
555 return 0;
556 buf[0] = 0;
557
558 rbot = cur = find_first_bit(maskp, nmaskbits);
559 while (cur < nmaskbits) {
560 rtop = cur;
561 cur = find_next_bit(maskp, nmaskbits, cur+1);
562 if (cur >= nmaskbits || cur > rtop + 1) {
563 len = bscnl_emit(buf, buflen, rbot, rtop, len);
564 rbot = cur;
565 }
566 }
567 return len;
568}
569EXPORT_SYMBOL(bitmap_scnlistprintf);
570
571/**
572 * __bitmap_parselist - convert list format ASCII string to bitmap
573 * @buf: read nul-terminated user string from this buffer
574 * @buflen: buffer size in bytes. If string is smaller than this
575 * then it must be terminated with a \0.
576 * @is_user: location of buffer, 0 indicates kernel space
577 * @maskp: write resulting mask here
578 * @nmaskbits: number of bits in mask to be written
579 *
580 * Input format is a comma-separated list of decimal numbers and
581 * ranges. Consecutively set bits are shown as two hyphen-separated
582 * decimal numbers, the smallest and largest bit numbers set in
583 * the range.
584 *
585 * Returns 0 on success, -errno on invalid input strings.
586 * Error values:
587 * %-EINVAL: second number in range smaller than first
588 * %-EINVAL: invalid character in string
589 * %-ERANGE: bit number specified too large for mask
590 */
591static int __bitmap_parselist(const char *buf, unsigned int buflen,
592 int is_user, unsigned long *maskp,
593 int nmaskbits)
594{
595 unsigned a, b;
596 int c, old_c, totaldigits;
597 const char __user *ubuf = buf;
598 int exp_digit, in_range;
599
600 totaldigits = c = 0;
601 bitmap_zero(maskp, nmaskbits);
602 do {
603 exp_digit = 1;
604 in_range = 0;
605 a = b = 0;
606
607 /* Get the next cpu# or a range of cpu#'s */
608 while (buflen) {
609 old_c = c;
610 if (is_user) {
611 if (__get_user(c, ubuf++))
612 return -EFAULT;
613 } else
614 c = *buf++;
615 buflen--;
616 if (isspace(c))
617 continue;
618
619 /*
620 * If the last character was a space and the current
621 * character isn't '\0', we've got embedded whitespace.
622 * This is a no-no, so throw an error.
623 */
624 if (totaldigits && c && isspace(old_c))
625 return -EINVAL;
626
627 /* A '\0' or a ',' signal the end of a cpu# or range */
628 if (c == '\0' || c == ',')
629 break;
630
631 if (c == '-') {
632 if (exp_digit || in_range)
633 return -EINVAL;
634 b = 0;
635 in_range = 1;
636 exp_digit = 1;
637 continue;
638 }
639
640 if (!isdigit(c))
641 return -EINVAL;
642
643 b = b * 10 + (c - '0');
644 if (!in_range)
645 a = b;
646 exp_digit = 0;
647 totaldigits++;
648 }
649 if (!(a <= b))
650 return -EINVAL;
651 if (b >= nmaskbits)
652 return -ERANGE;
653 while (a <= b) {
654 set_bit(a, maskp);
655 a++;
656 }
657 } while (buflen && c == ',');
658 return 0;
659}
660
661int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
662{
663 char *nl = strchr(bp, '\n');
664 int len;
665
666 if (nl)
667 len = nl - bp;
668 else
669 len = strlen(bp);
670
671 return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
672}
673EXPORT_SYMBOL(bitmap_parselist);
674
675
676/**
677 * bitmap_parselist_user()
678 *
679 * @ubuf: pointer to user buffer containing string.
680 * @ulen: buffer size in bytes. If string is smaller than this
681 * then it must be terminated with a \0.
682 * @maskp: pointer to bitmap array that will contain result.
683 * @nmaskbits: size of bitmap, in bits.
684 *
685 * Wrapper for bitmap_parselist(), providing it with user buffer.
686 *
687 * We cannot have this as an inline function in bitmap.h because it needs
688 * linux/uaccess.h to get the access_ok() declaration and this causes
689 * cyclic dependencies.
690 */
691int bitmap_parselist_user(const char __user *ubuf,
692 unsigned int ulen, unsigned long *maskp,
693 int nmaskbits)
694{
695 if (!access_ok(VERIFY_READ, ubuf, ulen))
696 return -EFAULT;
697 return __bitmap_parselist((const char *)ubuf,
698 ulen, 1, maskp, nmaskbits);
699}
700EXPORT_SYMBOL(bitmap_parselist_user);
701
702
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 < @bits)
707 * @bits: number of valid bit positions in @buf
708 *
709 * Map the bit at position @pos in @buf (of length @bits) 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 0. 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 */
721static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
722{
723 int i, ord;
724
725 if (pos < 0 || pos >= bits || !test_bit(pos, buf))
726 return -1;
727
728 i = find_first_bit(buf, bits);
729 ord = 0;
730 while (i < pos) {
731 i = find_next_bit(buf, bits, i + 1);
732 ord++;
733 }
734 BUG_ON(i != pos);
735
736 return ord;
737}
738
739/**
740 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
741 * @buf: pointer to bitmap
742 * @ord: ordinal bit position (n-th set bit, n >= 0)
743 * @bits: number of valid bit positions in @buf
744 *
745 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
746 * Value of @ord should be in range 0 <= @ord < weight(buf), else
747 * results are undefined.
748 *
749 * If for example, just bits 4 through 7 are set in @buf, then @ord
750 * values 0 through 3 will get mapped to 4 through 7, respectively,
751 * and all other @ord values return undefined values. When @ord value 3
752 * gets mapped to (returns) @pos value 7 in this example, that means
753 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
754 *
755 * The bit positions 0 through @bits are valid positions in @buf.
756 */
757int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
758{
759 int pos = 0;
760
761 if (ord >= 0 && ord < bits) {
762 int i;
763
764 for (i = find_first_bit(buf, bits);
765 i < bits && ord > 0;
766 i = find_next_bit(buf, bits, i + 1))
767 ord--;
768 if (i < bits && ord == 0)
769 pos = i;
770 }
771
772 return pos;
773}
774
775/**
776 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
777 * @dst: remapped result
778 * @src: subset to be remapped
779 * @old: defines domain of map
780 * @new: defines range of map
781 * @bits: number of bits in each of these bitmaps
782 *
783 * Let @old and @new define a mapping of bit positions, such that
784 * whatever position is held by the n-th set bit in @old is mapped
785 * to the n-th set bit in @new. In the more general case, allowing
786 * for the possibility that the weight 'w' of @new is less than the
787 * weight of @old, map the position of the n-th set bit in @old to
788 * the position of the m-th set bit in @new, where m == n % w.
789 *
790 * If either of the @old and @new bitmaps are empty, or if @src and
791 * @dst point to the same location, then this routine copies @src
792 * to @dst.
793 *
794 * The positions of unset bits in @old are mapped to themselves
795 * (the identify map).
796 *
797 * Apply the above specified mapping to @src, placing the result in
798 * @dst, clearing any bits previously set in @dst.
799 *
800 * For example, lets say that @old has bits 4 through 7 set, and
801 * @new has bits 12 through 15 set. This defines the mapping of bit
802 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
803 * bit positions unchanged. So if say @src comes into this routine
804 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
805 * 13 and 15 set.
806 */
807void bitmap_remap(unsigned long *dst, const unsigned long *src,
808 const unsigned long *old, const unsigned long *new,
809 int bits)
810{
811 int oldbit, w;
812
813 if (dst == src) /* following doesn't handle inplace remaps */
814 return;
815 bitmap_zero(dst, bits);
816
817 w = bitmap_weight(new, bits);
818 for_each_set_bit(oldbit, src, bits) {
819 int n = bitmap_pos_to_ord(old, oldbit, bits);
820
821 if (n < 0 || w == 0)
822 set_bit(oldbit, dst); /* identity map */
823 else
824 set_bit(bitmap_ord_to_pos(new, n % w, bits), dst);
825 }
826}
827EXPORT_SYMBOL(bitmap_remap);
828
829/**
830 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
831 * @oldbit: bit position to be mapped
832 * @old: defines domain of map
833 * @new: defines range of map
834 * @bits: number of bits in each of these bitmaps
835 *
836 * Let @old and @new define a mapping of bit positions, such that
837 * whatever position is held by the n-th set bit in @old is mapped
838 * to the n-th set bit in @new. In the more general case, allowing
839 * for the possibility that the weight 'w' of @new is less than the
840 * weight of @old, map the position of the n-th set bit in @old to
841 * the position of the m-th set bit in @new, where m == n % w.
842 *
843 * The positions of unset bits in @old are mapped to themselves
844 * (the identify map).
845 *
846 * Apply the above specified mapping to bit position @oldbit, returning
847 * the new bit position.
848 *
849 * For example, lets say that @old has bits 4 through 7 set, and
850 * @new has bits 12 through 15 set. This defines the mapping of bit
851 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
852 * bit positions unchanged. So if say @oldbit is 5, then this routine
853 * returns 13.
854 */
855int bitmap_bitremap(int oldbit, const unsigned long *old,
856 const unsigned long *new, int bits)
857{
858 int w = bitmap_weight(new, bits);
859 int n = bitmap_pos_to_ord(old, oldbit, bits);
860 if (n < 0 || w == 0)
861 return oldbit;
862 else
863 return bitmap_ord_to_pos(new, n % w, bits);
864}
865EXPORT_SYMBOL(bitmap_bitremap);
866
867/**
868 * bitmap_onto - translate one bitmap relative to another
869 * @dst: resulting translated bitmap
870 * @orig: original untranslated bitmap
871 * @relmap: bitmap relative to which translated
872 * @bits: number of bits in each of these bitmaps
873 *
874 * Set the n-th bit of @dst iff there exists some m such that the
875 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
876 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
877 * (If you understood the previous sentence the first time your
878 * read it, you're overqualified for your current job.)
879 *
880 * In other words, @orig is mapped onto (surjectively) @dst,
881 * using the the map { <n, m> | the n-th bit of @relmap is the
882 * m-th set bit of @relmap }.
883 *
884 * Any set bits in @orig above bit number W, where W is the
885 * weight of (number of set bits in) @relmap are mapped nowhere.
886 * In particular, if for all bits m set in @orig, m >= W, then
887 * @dst will end up empty. In situations where the possibility
888 * of such an empty result is not desired, one way to avoid it is
889 * to use the bitmap_fold() operator, below, to first fold the
890 * @orig bitmap over itself so that all its set bits x are in the
891 * range 0 <= x < W. The bitmap_fold() operator does this by
892 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
893 *
894 * Example [1] for bitmap_onto():
895 * Let's say @relmap has bits 30-39 set, and @orig has bits
896 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
897 * @dst will have bits 31, 33, 35, 37 and 39 set.
898 *
899 * When bit 0 is set in @orig, it means turn on the bit in
900 * @dst corresponding to whatever is the first bit (if any)
901 * that is turned on in @relmap. Since bit 0 was off in the
902 * above example, we leave off that bit (bit 30) in @dst.
903 *
904 * When bit 1 is set in @orig (as in the above example), it
905 * means turn on the bit in @dst corresponding to whatever
906 * is the second bit that is turned on in @relmap. The second
907 * bit in @relmap that was turned on in the above example was
908 * bit 31, so we turned on bit 31 in @dst.
909 *
910 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
911 * because they were the 4th, 6th, 8th and 10th set bits
912 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
913 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
914 *
915 * When bit 11 is set in @orig, it means turn on the bit in
916 * @dst corresponding to whatever is the twelfth bit that is
917 * turned on in @relmap. In the above example, there were
918 * only ten bits turned on in @relmap (30..39), so that bit
919 * 11 was set in @orig had no affect on @dst.
920 *
921 * Example [2] for bitmap_fold() + bitmap_onto():
922 * Let's say @relmap has these ten bits set:
923 * 40 41 42 43 45 48 53 61 74 95
924 * (for the curious, that's 40 plus the first ten terms of the
925 * Fibonacci sequence.)
926 *
927 * Further lets say we use the following code, invoking
928 * bitmap_fold() then bitmap_onto, as suggested above to
929 * avoid the possitility of an empty @dst result:
930 *
931 * unsigned long *tmp; // a temporary bitmap's bits
932 *
933 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
934 * bitmap_onto(dst, tmp, relmap, bits);
935 *
936 * Then this table shows what various values of @dst would be, for
937 * various @orig's. I list the zero-based positions of each set bit.
938 * The tmp column shows the intermediate result, as computed by
939 * using bitmap_fold() to fold the @orig bitmap modulo ten
940 * (the weight of @relmap).
941 *
942 * @orig tmp @dst
943 * 0 0 40
944 * 1 1 41
945 * 9 9 95
946 * 10 0 40 (*)
947 * 1 3 5 7 1 3 5 7 41 43 48 61
948 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
949 * 0 9 18 27 0 9 8 7 40 61 74 95
950 * 0 10 20 30 0 40
951 * 0 11 22 33 0 1 2 3 40 41 42 43
952 * 0 12 24 36 0 2 4 6 40 42 45 53
953 * 78 102 211 1 2 8 41 42 74 (*)
954 *
955 * (*) For these marked lines, if we hadn't first done bitmap_fold()
956 * into tmp, then the @dst result would have been empty.
957 *
958 * If either of @orig or @relmap is empty (no set bits), then @dst
959 * will be returned empty.
960 *
961 * If (as explained above) the only set bits in @orig are in positions
962 * m where m >= W, (where W is the weight of @relmap) then @dst will
963 * once again be returned empty.
964 *
965 * All bits in @dst not set by the above rule are cleared.
966 */
967void bitmap_onto(unsigned long *dst, const unsigned long *orig,
968 const unsigned long *relmap, int bits)
969{
970 int n, m; /* same meaning as in above comment */
971
972 if (dst == orig) /* following doesn't handle inplace mappings */
973 return;
974 bitmap_zero(dst, bits);
975
976 /*
977 * The following code is a more efficient, but less
978 * obvious, equivalent to the loop:
979 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
980 * n = bitmap_ord_to_pos(orig, m, bits);
981 * if (test_bit(m, orig))
982 * set_bit(n, dst);
983 * }
984 */
985
986 m = 0;
987 for_each_set_bit(n, relmap, bits) {
988 /* m == bitmap_pos_to_ord(relmap, n, bits) */
989 if (test_bit(m, orig))
990 set_bit(n, dst);
991 m++;
992 }
993}
994EXPORT_SYMBOL(bitmap_onto);
995
996/**
997 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
998 * @dst: resulting smaller bitmap
999 * @orig: original larger bitmap
1000 * @sz: specified size
1001 * @bits: number of bits in each of these bitmaps
1002 *
1003 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1004 * Clear all other bits in @dst. See further the comment and
1005 * Example [2] for bitmap_onto() for why and how to use this.
1006 */
1007void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1008 int sz, int bits)
1009{
1010 int oldbit;
1011
1012 if (dst == orig) /* following doesn't handle inplace mappings */
1013 return;
1014 bitmap_zero(dst, bits);
1015
1016 for_each_set_bit(oldbit, orig, bits)
1017 set_bit(oldbit % sz, dst);
1018}
1019EXPORT_SYMBOL(bitmap_fold);
1020
1021/*
1022 * Common code for bitmap_*_region() routines.
1023 * bitmap: array of unsigned longs corresponding to the bitmap
1024 * pos: the beginning of the region
1025 * order: region size (log base 2 of number of bits)
1026 * reg_op: operation(s) to perform on that region of bitmap
1027 *
1028 * Can set, verify and/or release a region of bits in a bitmap,
1029 * depending on which combination of REG_OP_* flag bits is set.
1030 *
1031 * A region of a bitmap is a sequence of bits in the bitmap, of
1032 * some size '1 << order' (a power of two), aligned to that same
1033 * '1 << order' power of two.
1034 *
1035 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1036 * Returns 0 in all other cases and reg_ops.
1037 */
1038
1039enum {
1040 REG_OP_ISFREE, /* true if region is all zero bits */
1041 REG_OP_ALLOC, /* set all bits in region */
1042 REG_OP_RELEASE, /* clear all bits in region */
1043};
1044
1045static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op)
1046{
1047 int nbits_reg; /* number of bits in region */
1048 int index; /* index first long of region in bitmap */
1049 int offset; /* bit offset region in bitmap[index] */
1050 int nlongs_reg; /* num longs spanned by region in bitmap */
1051 int nbitsinlong; /* num bits of region in each spanned long */
1052 unsigned long mask; /* bitmask for one long of region */
1053 int i; /* scans bitmap by longs */
1054 int ret = 0; /* return value */
1055
1056 /*
1057 * Either nlongs_reg == 1 (for small orders that fit in one long)
1058 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1059 */
1060 nbits_reg = 1 << order;
1061 index = pos / BITS_PER_LONG;
1062 offset = pos - (index * BITS_PER_LONG);
1063 nlongs_reg = BITS_TO_LONGS(nbits_reg);
1064 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1065
1066 /*
1067 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1068 * overflows if nbitsinlong == BITS_PER_LONG.
1069 */
1070 mask = (1UL << (nbitsinlong - 1));
1071 mask += mask - 1;
1072 mask <<= offset;
1073
1074 switch (reg_op) {
1075 case REG_OP_ISFREE:
1076 for (i = 0; i < nlongs_reg; i++) {
1077 if (bitmap[index + i] & mask)
1078 goto done;
1079 }
1080 ret = 1; /* all bits in region free (zero) */
1081 break;
1082
1083 case REG_OP_ALLOC:
1084 for (i = 0; i < nlongs_reg; i++)
1085 bitmap[index + i] |= mask;
1086 break;
1087
1088 case REG_OP_RELEASE:
1089 for (i = 0; i < nlongs_reg; i++)
1090 bitmap[index + i] &= ~mask;
1091 break;
1092 }
1093done:
1094 return ret;
1095}
1096
1097/**
1098 * bitmap_find_free_region - find a contiguous aligned mem region
1099 * @bitmap: array of unsigned longs corresponding to the bitmap
1100 * @bits: number of bits in the bitmap
1101 * @order: region size (log base 2 of number of bits) to find
1102 *
1103 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1104 * allocate them (set them to one). Only consider regions of length
1105 * a power (@order) of two, aligned to that power of two, which
1106 * makes the search algorithm much faster.
1107 *
1108 * Return the bit offset in bitmap of the allocated region,
1109 * or -errno on failure.
1110 */
1111int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
1112{
1113 int pos, end; /* scans bitmap by regions of size order */
1114
1115 for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) {
1116 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1117 continue;
1118 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1119 return pos;
1120 }
1121 return -ENOMEM;
1122}
1123EXPORT_SYMBOL(bitmap_find_free_region);
1124
1125/**
1126 * bitmap_release_region - release allocated bitmap region
1127 * @bitmap: array of unsigned longs corresponding to the bitmap
1128 * @pos: beginning of bit region to release
1129 * @order: region size (log base 2 of number of bits) to release
1130 *
1131 * This is the complement to __bitmap_find_free_region() and releases
1132 * the found region (by clearing it in the bitmap).
1133 *
1134 * No return value.
1135 */
1136void bitmap_release_region(unsigned long *bitmap, int pos, int order)
1137{
1138 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1139}
1140EXPORT_SYMBOL(bitmap_release_region);
1141
1142/**
1143 * bitmap_allocate_region - allocate bitmap region
1144 * @bitmap: array of unsigned longs corresponding to the bitmap
1145 * @pos: beginning of bit region to allocate
1146 * @order: region size (log base 2 of number of bits) to allocate
1147 *
1148 * Allocate (set bits in) a specified region of a bitmap.
1149 *
1150 * Return 0 on success, or %-EBUSY if specified region wasn't
1151 * free (not all bits were zero).
1152 */
1153int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
1154{
1155 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1156 return -EBUSY;
1157 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1158 return 0;
1159}
1160EXPORT_SYMBOL(bitmap_allocate_region);
1161
1162/**
1163 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1164 * @dst: destination buffer
1165 * @src: bitmap to copy
1166 * @nbits: number of bits in the bitmap
1167 *
1168 * Require nbits % BITS_PER_LONG == 0.
1169 */
1170void bitmap_copy_le(void *dst, const unsigned long *src, int nbits)
1171{
1172 unsigned long *d = dst;
1173 int i;
1174
1175 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1176 if (BITS_PER_LONG == 64)
1177 d[i] = cpu_to_le64(src[i]);
1178 else
1179 d[i] = cpu_to_le32(src[i]);
1180 }
1181}
1182EXPORT_SYMBOL(bitmap_copy_le);