projects/linux·blob v3.19 · refs

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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
16#include <asm/page.h>
17#include <asm/uaccess.h>
18
19/*
20 * bitmaps provide an array of bits, implemented using an an
21 * array of unsigned longs. The number of valid bits in a
22 * given bitmap does _not_ need to be an exact multiple of
23 * BITS_PER_LONG.
24 *
25 * The possible unused bits in the last, partially used word
26 * of a bitmap are 'don't care'. The implementation makes
27 * no particular effort to keep them zero. It ensures that
28 * their value will not affect the results of any operation.
29 * The bitmap operations that return Boolean (bitmap_empty,
30 * for example) or scalar (bitmap_weight, for example) results
31 * carefully filter out these unused bits from impacting their
32 * results.
33 *
34 * These operations actually hold to a slightly stronger rule:
35 * if you don't input any bitmaps to these ops that have some
36 * unused bits set, then they won't output any set unused bits
37 * in output bitmaps.
38 *
39 * The byte ordering of bitmaps is more natural on little
40 * endian architectures. See the big-endian headers
41 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
42 * for the best explanations of this ordering.
43 */
44
45int __bitmap_empty(const unsigned long *bitmap, unsigned int bits)
46{
47 unsigned int k, lim = bits/BITS_PER_LONG;
48 for (k = 0; k < lim; ++k)
49 if (bitmap[k])
50 return 0;
51
52 if (bits % BITS_PER_LONG)
53 if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
54 return 0;
55
56 return 1;
57}
58EXPORT_SYMBOL(__bitmap_empty);
59
60int __bitmap_full(const unsigned long *bitmap, unsigned int bits)
61{
62 unsigned int k, lim = bits/BITS_PER_LONG;
63 for (k = 0; k < lim; ++k)
64 if (~bitmap[k])
65 return 0;
66
67 if (bits % BITS_PER_LONG)
68 if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
69 return 0;
70
71 return 1;
72}
73EXPORT_SYMBOL(__bitmap_full);
74
75int __bitmap_equal(const unsigned long *bitmap1,
76 const unsigned long *bitmap2, unsigned int bits)
77{
78 unsigned int k, lim = bits/BITS_PER_LONG;
79 for (k = 0; k < lim; ++k)
80 if (bitmap1[k] != bitmap2[k])
81 return 0;
82
83 if (bits % BITS_PER_LONG)
84 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
85 return 0;
86
87 return 1;
88}
89EXPORT_SYMBOL(__bitmap_equal);
90
91void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
92{
93 unsigned int k, lim = bits/BITS_PER_LONG;
94 for (k = 0; k < lim; ++k)
95 dst[k] = ~src[k];
96
97 if (bits % BITS_PER_LONG)
98 dst[k] = ~src[k];
99}
100EXPORT_SYMBOL(__bitmap_complement);
101
102/**
103 * __bitmap_shift_right - logical right shift of the bits in a bitmap
104 * @dst : destination bitmap
105 * @src : source bitmap
106 * @shift : shift by this many bits
107 * @bits : bitmap size, in bits
108 *
109 * Shifting right (dividing) means moving bits in the MS -> LS bit
110 * direction. Zeros are fed into the vacated MS positions and the
111 * LS bits shifted off the bottom are lost.
112 */
113void __bitmap_shift_right(unsigned long *dst,
114 const unsigned long *src, int shift, int bits)
115{
116 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
117 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
118 unsigned long mask = (1UL << left) - 1;
119 for (k = 0; off + k < lim; ++k) {
120 unsigned long upper, lower;
121
122 /*
123 * If shift is not word aligned, take lower rem bits of
124 * word above and make them the top rem bits of result.
125 */
126 if (!rem || off + k + 1 >= lim)
127 upper = 0;
128 else {
129 upper = src[off + k + 1];
130 if (off + k + 1 == lim - 1 && left)
131 upper &= mask;
132 }
133 lower = src[off + k];
134 if (left && off + k == lim - 1)
135 lower &= mask;
136 dst[k] = lower >> rem;
137 if (rem)
138 dst[k] |= upper << (BITS_PER_LONG - rem);
139 if (left && k == lim - 1)
140 dst[k] &= mask;
141 }
142 if (off)
143 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
144}
145EXPORT_SYMBOL(__bitmap_shift_right);
146
147
148/**
149 * __bitmap_shift_left - logical left shift of the bits in a bitmap
150 * @dst : destination bitmap
151 * @src : source bitmap
152 * @shift : shift by this many bits
153 * @bits : bitmap size, in bits
154 *
155 * Shifting left (multiplying) means moving bits in the LS -> MS
156 * direction. Zeros are fed into the vacated LS bit positions
157 * and those MS bits shifted off the top are lost.
158 */
159
160void __bitmap_shift_left(unsigned long *dst,
161 const unsigned long *src, int shift, int bits)
162{
163 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
164 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
165 for (k = lim - off - 1; k >= 0; --k) {
166 unsigned long upper, lower;
167
168 /*
169 * If shift is not word aligned, take upper rem bits of
170 * word below and make them the bottom rem bits of result.
171 */
172 if (rem && k > 0)
173 lower = src[k - 1];
174 else
175 lower = 0;
176 upper = src[k];
177 if (left && k == lim - 1)
178 upper &= (1UL << left) - 1;
179 dst[k + off] = upper << rem;
180 if (rem)
181 dst[k + off] |= lower >> (BITS_PER_LONG - rem);
182 if (left && k + off == lim - 1)
183 dst[k + off] &= (1UL << left) - 1;
184 }
185 if (off)
186 memset(dst, 0, off*sizeof(unsigned long));
187}
188EXPORT_SYMBOL(__bitmap_shift_left);
189
190int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
191 const unsigned long *bitmap2, unsigned int bits)
192{
193 unsigned int k;
194 unsigned int lim = bits/BITS_PER_LONG;
195 unsigned long result = 0;
196
197 for (k = 0; k < lim; k++)
198 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
199 if (bits % BITS_PER_LONG)
200 result |= (dst[k] = bitmap1[k] & bitmap2[k] &
201 BITMAP_LAST_WORD_MASK(bits));
202 return result != 0;
203}
204EXPORT_SYMBOL(__bitmap_and);
205
206void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
207 const unsigned long *bitmap2, unsigned int bits)
208{
209 unsigned int k;
210 unsigned 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_or);
216
217void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
218 const unsigned long *bitmap2, unsigned int bits)
219{
220 unsigned int k;
221 unsigned int nr = BITS_TO_LONGS(bits);
222
223 for (k = 0; k < nr; k++)
224 dst[k] = bitmap1[k] ^ bitmap2[k];
225}
226EXPORT_SYMBOL(__bitmap_xor);
227
228int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
229 const unsigned long *bitmap2, unsigned int bits)
230{
231 unsigned int k;
232 unsigned int lim = bits/BITS_PER_LONG;
233 unsigned long result = 0;
234
235 for (k = 0; k < lim; k++)
236 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
237 if (bits % BITS_PER_LONG)
238 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
239 BITMAP_LAST_WORD_MASK(bits));
240 return result != 0;
241}
242EXPORT_SYMBOL(__bitmap_andnot);
243
244int __bitmap_intersects(const unsigned long *bitmap1,
245 const unsigned long *bitmap2, unsigned int bits)
246{
247 unsigned int k, lim = bits/BITS_PER_LONG;
248 for (k = 0; k < lim; ++k)
249 if (bitmap1[k] & bitmap2[k])
250 return 1;
251
252 if (bits % BITS_PER_LONG)
253 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
254 return 1;
255 return 0;
256}
257EXPORT_SYMBOL(__bitmap_intersects);
258
259int __bitmap_subset(const unsigned long *bitmap1,
260 const unsigned long *bitmap2, unsigned int bits)
261{
262 unsigned int k, lim = bits/BITS_PER_LONG;
263 for (k = 0; k < lim; ++k)
264 if (bitmap1[k] & ~bitmap2[k])
265 return 0;
266
267 if (bits % BITS_PER_LONG)
268 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
269 return 0;
270 return 1;
271}
272EXPORT_SYMBOL(__bitmap_subset);
273
274int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
275{
276 unsigned int k, lim = bits/BITS_PER_LONG;
277 int w = 0;
278
279 for (k = 0; k < lim; k++)
280 w += hweight_long(bitmap[k]);
281
282 if (bits % BITS_PER_LONG)
283 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
284
285 return w;
286}
287EXPORT_SYMBOL(__bitmap_weight);
288
289void bitmap_set(unsigned long *map, unsigned int start, int len)
290{
291 unsigned long *p = map + BIT_WORD(start);
292 const unsigned int size = start + len;
293 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
294 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
295
296 while (len - bits_to_set >= 0) {
297 *p |= mask_to_set;
298 len -= bits_to_set;
299 bits_to_set = BITS_PER_LONG;
300 mask_to_set = ~0UL;
301 p++;
302 }
303 if (len) {
304 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
305 *p |= mask_to_set;
306 }
307}
308EXPORT_SYMBOL(bitmap_set);
309
310void bitmap_clear(unsigned long *map, unsigned int start, int len)
311{
312 unsigned long *p = map + BIT_WORD(start);
313 const unsigned int size = start + len;
314 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
315 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
316
317 while (len - bits_to_clear >= 0) {
318 *p &= ~mask_to_clear;
319 len -= bits_to_clear;
320 bits_to_clear = BITS_PER_LONG;
321 mask_to_clear = ~0UL;
322 p++;
323 }
324 if (len) {
325 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
326 *p &= ~mask_to_clear;
327 }
328}
329EXPORT_SYMBOL(bitmap_clear);
330
331/**
332 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
333 * @map: The address to base the search on
334 * @size: The bitmap size in bits
335 * @start: The bitnumber to start searching at
336 * @nr: The number of zeroed bits we're looking for
337 * @align_mask: Alignment mask for zero area
338 * @align_offset: Alignment offset for zero area.
339 *
340 * The @align_mask should be one less than a power of 2; the effect is that
341 * the bit offset of all zero areas this function finds plus @align_offset
342 * is multiple of that power of 2.
343 */
344unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
345 unsigned long size,
346 unsigned long start,
347 unsigned int nr,
348 unsigned long align_mask,
349 unsigned long align_offset)
350{
351 unsigned long index, end, i;
352again:
353 index = find_next_zero_bit(map, size, start);
354
355 /* Align allocation */
356 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
357
358 end = index + nr;
359 if (end > size)
360 return end;
361 i = find_next_bit(map, end, index);
362 if (i < end) {
363 start = i + 1;
364 goto again;
365 }
366 return index;
367}
368EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
369
370/*
371 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
372 * second version by Paul Jackson, third by Joe Korty.
373 */
374
375#define CHUNKSZ 32
376#define nbits_to_hold_value(val) fls(val)
377#define BASEDEC 10 /* fancier cpuset lists input in decimal */
378
379/**
380 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
381 * @buf: byte buffer into which string is placed
382 * @buflen: reserved size of @buf, in bytes
383 * @maskp: pointer to bitmap to convert
384 * @nmaskbits: size of bitmap, in bits
385 *
386 * Exactly @nmaskbits bits are displayed. Hex digits are grouped into
387 * comma-separated sets of eight digits per set. Returns the number of
388 * characters which were written to *buf, excluding the trailing \0.
389 */
390int bitmap_scnprintf(char *buf, unsigned int buflen,
391 const unsigned long *maskp, int nmaskbits)
392{
393 int i, word, bit, len = 0;
394 unsigned long val;
395 const char *sep = "";
396 int chunksz;
397 u32 chunkmask;
398
399 chunksz = nmaskbits & (CHUNKSZ - 1);
400 if (chunksz == 0)
401 chunksz = CHUNKSZ;
402
403 i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
404 for (; i >= 0; i -= CHUNKSZ) {
405 chunkmask = ((1ULL << chunksz) - 1);
406 word = i / BITS_PER_LONG;
407 bit = i % BITS_PER_LONG;
408 val = (maskp[word] >> bit) & chunkmask;
409 len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
410 (chunksz+3)/4, val);
411 chunksz = CHUNKSZ;
412 sep = ",";
413 }
414 return len;
415}
416EXPORT_SYMBOL(bitmap_scnprintf);
417
418/**
419 * __bitmap_parse - convert an ASCII hex string into a bitmap.
420 * @buf: pointer to buffer containing string.
421 * @buflen: buffer size in bytes. If string is smaller than this
422 * then it must be terminated with a \0.
423 * @is_user: location of buffer, 0 indicates kernel space
424 * @maskp: pointer to bitmap array that will contain result.
425 * @nmaskbits: size of bitmap, in bits.
426 *
427 * Commas group hex digits into chunks. Each chunk defines exactly 32
428 * bits of the resultant bitmask. No chunk may specify a value larger
429 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
430 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
431 * characters and for grouping errors such as "1,,5", ",44", "," and "".
432 * Leading and trailing whitespace accepted, but not embedded whitespace.
433 */
434int __bitmap_parse(const char *buf, unsigned int buflen,
435 int is_user, unsigned long *maskp,
436 int nmaskbits)
437{
438 int c, old_c, totaldigits, ndigits, nchunks, nbits;
439 u32 chunk;
440 const char __user __force *ubuf = (const char __user __force *)buf;
441
442 bitmap_zero(maskp, nmaskbits);
443
444 nchunks = nbits = totaldigits = c = 0;
445 do {
446 chunk = ndigits = 0;
447
448 /* Get the next chunk of the bitmap */
449 while (buflen) {
450 old_c = c;
451 if (is_user) {
452 if (__get_user(c, ubuf++))
453 return -EFAULT;
454 }
455 else
456 c = *buf++;
457 buflen--;
458 if (isspace(c))
459 continue;
460
461 /*
462 * If the last character was a space and the current
463 * character isn't '\0', we've got embedded whitespace.
464 * This is a no-no, so throw an error.
465 */
466 if (totaldigits && c && isspace(old_c))
467 return -EINVAL;
468
469 /* A '\0' or a ',' signal the end of the chunk */
470 if (c == '\0' || c == ',')
471 break;
472
473 if (!isxdigit(c))
474 return -EINVAL;
475
476 /*
477 * Make sure there are at least 4 free bits in 'chunk'.
478 * If not, this hexdigit will overflow 'chunk', so
479 * throw an error.
480 */
481 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
482 return -EOVERFLOW;
483
484 chunk = (chunk << 4) | hex_to_bin(c);
485 ndigits++; totaldigits++;
486 }
487 if (ndigits == 0)
488 return -EINVAL;
489 if (nchunks == 0 && chunk == 0)
490 continue;
491
492 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
493 *maskp |= chunk;
494 nchunks++;
495 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
496 if (nbits > nmaskbits)
497 return -EOVERFLOW;
498 } while (buflen && c == ',');
499
500 return 0;
501}
502EXPORT_SYMBOL(__bitmap_parse);
503
504/**
505 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
506 *
507 * @ubuf: pointer to user buffer containing string.
508 * @ulen: buffer size in bytes. If string is smaller than this
509 * then it must be terminated with a \0.
510 * @maskp: pointer to bitmap array that will contain result.
511 * @nmaskbits: size of bitmap, in bits.
512 *
513 * Wrapper for __bitmap_parse(), providing it with user buffer.
514 *
515 * We cannot have this as an inline function in bitmap.h because it needs
516 * linux/uaccess.h to get the access_ok() declaration and this causes
517 * cyclic dependencies.
518 */
519int bitmap_parse_user(const char __user *ubuf,
520 unsigned int ulen, unsigned long *maskp,
521 int nmaskbits)
522{
523 if (!access_ok(VERIFY_READ, ubuf, ulen))
524 return -EFAULT;
525 return __bitmap_parse((const char __force *)ubuf,
526 ulen, 1, maskp, nmaskbits);
527
528}
529EXPORT_SYMBOL(bitmap_parse_user);
530
531/*
532 * bscnl_emit(buf, buflen, rbot, rtop, bp)
533 *
534 * Helper routine for bitmap_scnlistprintf(). Write decimal number
535 * or range to buf, suppressing output past buf+buflen, with optional
536 * comma-prefix. Return len of what was written to *buf, excluding the
537 * trailing \0.
538 */
539static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
540{
541 if (len > 0)
542 len += scnprintf(buf + len, buflen - len, ",");
543 if (rbot == rtop)
544 len += scnprintf(buf + len, buflen - len, "%d", rbot);
545 else
546 len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
547 return len;
548}
549
550/**
551 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
552 * @buf: byte buffer into which string is placed
553 * @buflen: reserved size of @buf, in bytes
554 * @maskp: pointer to bitmap to convert
555 * @nmaskbits: size of bitmap, in bits
556 *
557 * Output format is a comma-separated list of decimal numbers and
558 * ranges. Consecutively set bits are shown as two hyphen-separated
559 * decimal numbers, the smallest and largest bit numbers set in
560 * the range. Output format is compatible with the format
561 * accepted as input by bitmap_parselist().
562 *
563 * The return value is the number of characters which were written to *buf
564 * excluding the trailing '\0', as per ISO C99's scnprintf.
565 */
566int bitmap_scnlistprintf(char *buf, unsigned int buflen,
567 const unsigned long *maskp, int nmaskbits)
568{
569 int len = 0;
570 /* current bit is 'cur', most recently seen range is [rbot, rtop] */
571 int cur, rbot, rtop;
572
573 if (buflen == 0)
574 return 0;
575 buf[0] = 0;
576
577 rbot = cur = find_first_bit(maskp, nmaskbits);
578 while (cur < nmaskbits) {
579 rtop = cur;
580 cur = find_next_bit(maskp, nmaskbits, cur+1);
581 if (cur >= nmaskbits || cur > rtop + 1) {
582 len = bscnl_emit(buf, buflen, rbot, rtop, len);
583 rbot = cur;
584 }
585 }
586 return len;
587}
588EXPORT_SYMBOL(bitmap_scnlistprintf);
589
590/**
591 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
592 * @list: indicates whether the bitmap must be list
593 * @buf: page aligned buffer into which string is placed
594 * @maskp: pointer to bitmap to convert
595 * @nmaskbits: size of bitmap, in bits
596 *
597 * Output format is a comma-separated list of decimal numbers and
598 * ranges if list is specified or hex digits grouped into comma-separated
599 * sets of 8 digits/set. Returns the number of characters written to buf.
600 */
601int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
602 int nmaskbits)
603{
604 ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf - 2;
605 int n = 0;
606
607 if (len > 1) {
608 n = list ? bitmap_scnlistprintf(buf, len, maskp, nmaskbits) :
609 bitmap_scnprintf(buf, len, maskp, nmaskbits);
610 buf[n++] = '\n';
611 buf[n] = '\0';
612 }
613 return n;
614}
615EXPORT_SYMBOL(bitmap_print_to_pagebuf);
616
617/**
618 * __bitmap_parselist - convert list format ASCII string to bitmap
619 * @buf: read nul-terminated user string from this buffer
620 * @buflen: buffer size in bytes. If string is smaller than this
621 * then it must be terminated with a \0.
622 * @is_user: location of buffer, 0 indicates kernel space
623 * @maskp: write resulting mask here
624 * @nmaskbits: number of bits in mask to be written
625 *
626 * Input format is a comma-separated list of decimal numbers and
627 * ranges. Consecutively set bits are shown as two hyphen-separated
628 * decimal numbers, the smallest and largest bit numbers set in
629 * the range.
630 *
631 * Returns 0 on success, -errno on invalid input strings.
632 * Error values:
633 * %-EINVAL: second number in range smaller than first
634 * %-EINVAL: invalid character in string
635 * %-ERANGE: bit number specified too large for mask
636 */
637static int __bitmap_parselist(const char *buf, unsigned int buflen,
638 int is_user, unsigned long *maskp,
639 int nmaskbits)
640{
641 unsigned a, b;
642 int c, old_c, totaldigits;
643 const char __user __force *ubuf = (const char __user __force *)buf;
644 int exp_digit, in_range;
645
646 totaldigits = c = 0;
647 bitmap_zero(maskp, nmaskbits);
648 do {
649 exp_digit = 1;
650 in_range = 0;
651 a = b = 0;
652
653 /* Get the next cpu# or a range of cpu#'s */
654 while (buflen) {
655 old_c = c;
656 if (is_user) {
657 if (__get_user(c, ubuf++))
658 return -EFAULT;
659 } else
660 c = *buf++;
661 buflen--;
662 if (isspace(c))
663 continue;
664
665 /*
666 * If the last character was a space and the current
667 * character isn't '\0', we've got embedded whitespace.
668 * This is a no-no, so throw an error.
669 */
670 if (totaldigits && c && isspace(old_c))
671 return -EINVAL;
672
673 /* A '\0' or a ',' signal the end of a cpu# or range */
674 if (c == '\0' || c == ',')
675 break;
676
677 if (c == '-') {
678 if (exp_digit || in_range)
679 return -EINVAL;
680 b = 0;
681 in_range = 1;
682 exp_digit = 1;
683 continue;
684 }
685
686 if (!isdigit(c))
687 return -EINVAL;
688
689 b = b * 10 + (c - '0');
690 if (!in_range)
691 a = b;
692 exp_digit = 0;
693 totaldigits++;
694 }
695 if (!(a <= b))
696 return -EINVAL;
697 if (b >= nmaskbits)
698 return -ERANGE;
699 while (a <= b) {
700 set_bit(a, maskp);
701 a++;
702 }
703 } while (buflen && c == ',');
704 return 0;
705}
706
707int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
708{
709 char *nl = strchrnul(bp, '\n');
710 int len = nl - bp;
711
712 return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
713}
714EXPORT_SYMBOL(bitmap_parselist);
715
716
717/**
718 * bitmap_parselist_user()
719 *
720 * @ubuf: pointer to user buffer containing string.
721 * @ulen: buffer size in bytes. If string is smaller than this
722 * then it must be terminated with a \0.
723 * @maskp: pointer to bitmap array that will contain result.
724 * @nmaskbits: size of bitmap, in bits.
725 *
726 * Wrapper for bitmap_parselist(), providing it with user buffer.
727 *
728 * We cannot have this as an inline function in bitmap.h because it needs
729 * linux/uaccess.h to get the access_ok() declaration and this causes
730 * cyclic dependencies.
731 */
732int bitmap_parselist_user(const char __user *ubuf,
733 unsigned int ulen, unsigned long *maskp,
734 int nmaskbits)
735{
736 if (!access_ok(VERIFY_READ, ubuf, ulen))
737 return -EFAULT;
738 return __bitmap_parselist((const char __force *)ubuf,
739 ulen, 1, maskp, nmaskbits);
740}
741EXPORT_SYMBOL(bitmap_parselist_user);
742
743
744/**
745 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
746 * @buf: pointer to a bitmap
747 * @pos: a bit position in @buf (0 <= @pos < @bits)
748 * @bits: number of valid bit positions in @buf
749 *
750 * Map the bit at position @pos in @buf (of length @bits) to the
751 * ordinal of which set bit it is. If it is not set or if @pos
752 * is not a valid bit position, map to -1.
753 *
754 * If for example, just bits 4 through 7 are set in @buf, then @pos
755 * values 4 through 7 will get mapped to 0 through 3, respectively,
756 * and other @pos values will get mapped to -1. When @pos value 7
757 * gets mapped to (returns) @ord value 3 in this example, that means
758 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
759 *
760 * The bit positions 0 through @bits are valid positions in @buf.
761 */
762static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
763{
764 int i, ord;
765
766 if (pos < 0 || pos >= bits || !test_bit(pos, buf))
767 return -1;
768
769 i = find_first_bit(buf, bits);
770 ord = 0;
771 while (i < pos) {
772 i = find_next_bit(buf, bits, i + 1);
773 ord++;
774 }
775 BUG_ON(i != pos);
776
777 return ord;
778}
779
780/**
781 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
782 * @buf: pointer to bitmap
783 * @ord: ordinal bit position (n-th set bit, n >= 0)
784 * @bits: number of valid bit positions in @buf
785 *
786 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
787 * Value of @ord should be in range 0 <= @ord < weight(buf), else
788 * results are undefined.
789 *
790 * If for example, just bits 4 through 7 are set in @buf, then @ord
791 * values 0 through 3 will get mapped to 4 through 7, respectively,
792 * and all other @ord values return undefined values. When @ord value 3
793 * gets mapped to (returns) @pos value 7 in this example, that means
794 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
795 *
796 * The bit positions 0 through @bits are valid positions in @buf.
797 */
798int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
799{
800 int pos = 0;
801
802 if (ord >= 0 && ord < bits) {
803 int i;
804
805 for (i = find_first_bit(buf, bits);
806 i < bits && ord > 0;
807 i = find_next_bit(buf, bits, i + 1))
808 ord--;
809 if (i < bits && ord == 0)
810 pos = i;
811 }
812
813 return pos;
814}
815
816/**
817 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
818 * @dst: remapped result
819 * @src: subset to be remapped
820 * @old: defines domain of map
821 * @new: defines range of map
822 * @bits: number of bits in each of these bitmaps
823 *
824 * Let @old and @new define a mapping of bit positions, such that
825 * whatever position is held by the n-th set bit in @old is mapped
826 * to the n-th set bit in @new. In the more general case, allowing
827 * for the possibility that the weight 'w' of @new is less than the
828 * weight of @old, map the position of the n-th set bit in @old to
829 * the position of the m-th set bit in @new, where m == n % w.
830 *
831 * If either of the @old and @new bitmaps are empty, or if @src and
832 * @dst point to the same location, then this routine copies @src
833 * to @dst.
834 *
835 * The positions of unset bits in @old are mapped to themselves
836 * (the identify map).
837 *
838 * Apply the above specified mapping to @src, placing the result in
839 * @dst, clearing any bits previously set in @dst.
840 *
841 * For example, lets say that @old has bits 4 through 7 set, and
842 * @new has bits 12 through 15 set. This defines the mapping of bit
843 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
844 * bit positions unchanged. So if say @src comes into this routine
845 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
846 * 13 and 15 set.
847 */
848void bitmap_remap(unsigned long *dst, const unsigned long *src,
849 const unsigned long *old, const unsigned long *new,
850 int bits)
851{
852 int oldbit, w;
853
854 if (dst == src) /* following doesn't handle inplace remaps */
855 return;
856 bitmap_zero(dst, bits);
857
858 w = bitmap_weight(new, bits);
859 for_each_set_bit(oldbit, src, bits) {
860 int n = bitmap_pos_to_ord(old, oldbit, bits);
861
862 if (n < 0 || w == 0)
863 set_bit(oldbit, dst); /* identity map */
864 else
865 set_bit(bitmap_ord_to_pos(new, n % w, bits), dst);
866 }
867}
868EXPORT_SYMBOL(bitmap_remap);
869
870/**
871 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
872 * @oldbit: bit position to be mapped
873 * @old: defines domain of map
874 * @new: defines range of map
875 * @bits: number of bits in each of these bitmaps
876 *
877 * Let @old and @new define a mapping of bit positions, such that
878 * whatever position is held by the n-th set bit in @old is mapped
879 * to the n-th set bit in @new. In the more general case, allowing
880 * for the possibility that the weight 'w' of @new is less than the
881 * weight of @old, map the position of the n-th set bit in @old to
882 * the position of the m-th set bit in @new, where m == n % w.
883 *
884 * The positions of unset bits in @old are mapped to themselves
885 * (the identify map).
886 *
887 * Apply the above specified mapping to bit position @oldbit, returning
888 * the new bit position.
889 *
890 * For example, lets say that @old has bits 4 through 7 set, and
891 * @new has bits 12 through 15 set. This defines the mapping of bit
892 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
893 * bit positions unchanged. So if say @oldbit is 5, then this routine
894 * returns 13.
895 */
896int bitmap_bitremap(int oldbit, const unsigned long *old,
897 const unsigned long *new, int bits)
898{
899 int w = bitmap_weight(new, bits);
900 int n = bitmap_pos_to_ord(old, oldbit, bits);
901 if (n < 0 || w == 0)
902 return oldbit;
903 else
904 return bitmap_ord_to_pos(new, n % w, bits);
905}
906EXPORT_SYMBOL(bitmap_bitremap);
907
908/**
909 * bitmap_onto - translate one bitmap relative to another
910 * @dst: resulting translated bitmap
911 * @orig: original untranslated bitmap
912 * @relmap: bitmap relative to which translated
913 * @bits: number of bits in each of these bitmaps
914 *
915 * Set the n-th bit of @dst iff there exists some m such that the
916 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
917 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
918 * (If you understood the previous sentence the first time your
919 * read it, you're overqualified for your current job.)
920 *
921 * In other words, @orig is mapped onto (surjectively) @dst,
922 * using the map { <n, m> | the n-th bit of @relmap is the
923 * m-th set bit of @relmap }.
924 *
925 * Any set bits in @orig above bit number W, where W is the
926 * weight of (number of set bits in) @relmap are mapped nowhere.
927 * In particular, if for all bits m set in @orig, m >= W, then
928 * @dst will end up empty. In situations where the possibility
929 * of such an empty result is not desired, one way to avoid it is
930 * to use the bitmap_fold() operator, below, to first fold the
931 * @orig bitmap over itself so that all its set bits x are in the
932 * range 0 <= x < W. The bitmap_fold() operator does this by
933 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
934 *
935 * Example [1] for bitmap_onto():
936 * Let's say @relmap has bits 30-39 set, and @orig has bits
937 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
938 * @dst will have bits 31, 33, 35, 37 and 39 set.
939 *
940 * When bit 0 is set in @orig, it means turn on the bit in
941 * @dst corresponding to whatever is the first bit (if any)
942 * that is turned on in @relmap. Since bit 0 was off in the
943 * above example, we leave off that bit (bit 30) in @dst.
944 *
945 * When bit 1 is set in @orig (as in the above example), it
946 * means turn on the bit in @dst corresponding to whatever
947 * is the second bit that is turned on in @relmap. The second
948 * bit in @relmap that was turned on in the above example was
949 * bit 31, so we turned on bit 31 in @dst.
950 *
951 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
952 * because they were the 4th, 6th, 8th and 10th set bits
953 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
954 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
955 *
956 * When bit 11 is set in @orig, it means turn on the bit in
957 * @dst corresponding to whatever is the twelfth bit that is
958 * turned on in @relmap. In the above example, there were
959 * only ten bits turned on in @relmap (30..39), so that bit
960 * 11 was set in @orig had no affect on @dst.
961 *
962 * Example [2] for bitmap_fold() + bitmap_onto():
963 * Let's say @relmap has these ten bits set:
964 * 40 41 42 43 45 48 53 61 74 95
965 * (for the curious, that's 40 plus the first ten terms of the
966 * Fibonacci sequence.)
967 *
968 * Further lets say we use the following code, invoking
969 * bitmap_fold() then bitmap_onto, as suggested above to
970 * avoid the possibility of an empty @dst result:
971 *
972 * unsigned long *tmp; // a temporary bitmap's bits
973 *
974 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
975 * bitmap_onto(dst, tmp, relmap, bits);
976 *
977 * Then this table shows what various values of @dst would be, for
978 * various @orig's. I list the zero-based positions of each set bit.
979 * The tmp column shows the intermediate result, as computed by
980 * using bitmap_fold() to fold the @orig bitmap modulo ten
981 * (the weight of @relmap).
982 *
983 * @orig tmp @dst
984 * 0 0 40
985 * 1 1 41
986 * 9 9 95
987 * 10 0 40 (*)
988 * 1 3 5 7 1 3 5 7 41 43 48 61
989 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
990 * 0 9 18 27 0 9 8 7 40 61 74 95
991 * 0 10 20 30 0 40
992 * 0 11 22 33 0 1 2 3 40 41 42 43
993 * 0 12 24 36 0 2 4 6 40 42 45 53
994 * 78 102 211 1 2 8 41 42 74 (*)
995 *
996 * (*) For these marked lines, if we hadn't first done bitmap_fold()
997 * into tmp, then the @dst result would have been empty.
998 *
999 * If either of @orig or @relmap is empty (no set bits), then @dst
1000 * will be returned empty.
1001 *
1002 * If (as explained above) the only set bits in @orig are in positions
1003 * m where m >= W, (where W is the weight of @relmap) then @dst will
1004 * once again be returned empty.
1005 *
1006 * All bits in @dst not set by the above rule are cleared.
1007 */
1008void bitmap_onto(unsigned long *dst, const unsigned long *orig,
1009 const unsigned long *relmap, int bits)
1010{
1011 int n, m; /* same meaning as in above comment */
1012
1013 if (dst == orig) /* following doesn't handle inplace mappings */
1014 return;
1015 bitmap_zero(dst, bits);
1016
1017 /*
1018 * The following code is a more efficient, but less
1019 * obvious, equivalent to the loop:
1020 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
1021 * n = bitmap_ord_to_pos(orig, m, bits);
1022 * if (test_bit(m, orig))
1023 * set_bit(n, dst);
1024 * }
1025 */
1026
1027 m = 0;
1028 for_each_set_bit(n, relmap, bits) {
1029 /* m == bitmap_pos_to_ord(relmap, n, bits) */
1030 if (test_bit(m, orig))
1031 set_bit(n, dst);
1032 m++;
1033 }
1034}
1035EXPORT_SYMBOL(bitmap_onto);
1036
1037/**
1038 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
1039 * @dst: resulting smaller bitmap
1040 * @orig: original larger bitmap
1041 * @sz: specified size
1042 * @bits: number of bits in each of these bitmaps
1043 *
1044 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1045 * Clear all other bits in @dst. See further the comment and
1046 * Example [2] for bitmap_onto() for why and how to use this.
1047 */
1048void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1049 int sz, int bits)
1050{
1051 int oldbit;
1052
1053 if (dst == orig) /* following doesn't handle inplace mappings */
1054 return;
1055 bitmap_zero(dst, bits);
1056
1057 for_each_set_bit(oldbit, orig, bits)
1058 set_bit(oldbit % sz, dst);
1059}
1060EXPORT_SYMBOL(bitmap_fold);
1061
1062/*
1063 * Common code for bitmap_*_region() routines.
1064 * bitmap: array of unsigned longs corresponding to the bitmap
1065 * pos: the beginning of the region
1066 * order: region size (log base 2 of number of bits)
1067 * reg_op: operation(s) to perform on that region of bitmap
1068 *
1069 * Can set, verify and/or release a region of bits in a bitmap,
1070 * depending on which combination of REG_OP_* flag bits is set.
1071 *
1072 * A region of a bitmap is a sequence of bits in the bitmap, of
1073 * some size '1 << order' (a power of two), aligned to that same
1074 * '1 << order' power of two.
1075 *
1076 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1077 * Returns 0 in all other cases and reg_ops.
1078 */
1079
1080enum {
1081 REG_OP_ISFREE, /* true if region is all zero bits */
1082 REG_OP_ALLOC, /* set all bits in region */
1083 REG_OP_RELEASE, /* clear all bits in region */
1084};
1085
1086static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
1087{
1088 int nbits_reg; /* number of bits in region */
1089 int index; /* index first long of region in bitmap */
1090 int offset; /* bit offset region in bitmap[index] */
1091 int nlongs_reg; /* num longs spanned by region in bitmap */
1092 int nbitsinlong; /* num bits of region in each spanned long */
1093 unsigned long mask; /* bitmask for one long of region */
1094 int i; /* scans bitmap by longs */
1095 int ret = 0; /* return value */
1096
1097 /*
1098 * Either nlongs_reg == 1 (for small orders that fit in one long)
1099 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1100 */
1101 nbits_reg = 1 << order;
1102 index = pos / BITS_PER_LONG;
1103 offset = pos - (index * BITS_PER_LONG);
1104 nlongs_reg = BITS_TO_LONGS(nbits_reg);
1105 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1106
1107 /*
1108 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1109 * overflows if nbitsinlong == BITS_PER_LONG.
1110 */
1111 mask = (1UL << (nbitsinlong - 1));
1112 mask += mask - 1;
1113 mask <<= offset;
1114
1115 switch (reg_op) {
1116 case REG_OP_ISFREE:
1117 for (i = 0; i < nlongs_reg; i++) {
1118 if (bitmap[index + i] & mask)
1119 goto done;
1120 }
1121 ret = 1; /* all bits in region free (zero) */
1122 break;
1123
1124 case REG_OP_ALLOC:
1125 for (i = 0; i < nlongs_reg; i++)
1126 bitmap[index + i] |= mask;
1127 break;
1128
1129 case REG_OP_RELEASE:
1130 for (i = 0; i < nlongs_reg; i++)
1131 bitmap[index + i] &= ~mask;
1132 break;
1133 }
1134done:
1135 return ret;
1136}
1137
1138/**
1139 * bitmap_find_free_region - find a contiguous aligned mem region
1140 * @bitmap: array of unsigned longs corresponding to the bitmap
1141 * @bits: number of bits in the bitmap
1142 * @order: region size (log base 2 of number of bits) to find
1143 *
1144 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1145 * allocate them (set them to one). Only consider regions of length
1146 * a power (@order) of two, aligned to that power of two, which
1147 * makes the search algorithm much faster.
1148 *
1149 * Return the bit offset in bitmap of the allocated region,
1150 * or -errno on failure.
1151 */
1152int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
1153{
1154 unsigned int pos, end; /* scans bitmap by regions of size order */
1155
1156 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
1157 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1158 continue;
1159 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1160 return pos;
1161 }
1162 return -ENOMEM;
1163}
1164EXPORT_SYMBOL(bitmap_find_free_region);
1165
1166/**
1167 * bitmap_release_region - release allocated bitmap region
1168 * @bitmap: array of unsigned longs corresponding to the bitmap
1169 * @pos: beginning of bit region to release
1170 * @order: region size (log base 2 of number of bits) to release
1171 *
1172 * This is the complement to __bitmap_find_free_region() and releases
1173 * the found region (by clearing it in the bitmap).
1174 *
1175 * No return value.
1176 */
1177void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
1178{
1179 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1180}
1181EXPORT_SYMBOL(bitmap_release_region);
1182
1183/**
1184 * bitmap_allocate_region - allocate bitmap region
1185 * @bitmap: array of unsigned longs corresponding to the bitmap
1186 * @pos: beginning of bit region to allocate
1187 * @order: region size (log base 2 of number of bits) to allocate
1188 *
1189 * Allocate (set bits in) a specified region of a bitmap.
1190 *
1191 * Return 0 on success, or %-EBUSY if specified region wasn't
1192 * free (not all bits were zero).
1193 */
1194int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
1195{
1196 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1197 return -EBUSY;
1198 return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1199}
1200EXPORT_SYMBOL(bitmap_allocate_region);
1201
1202/**
1203 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1204 * @dst: destination buffer
1205 * @src: bitmap to copy
1206 * @nbits: number of bits in the bitmap
1207 *
1208 * Require nbits % BITS_PER_LONG == 0.
1209 */
1210void bitmap_copy_le(void *dst, const unsigned long *src, int nbits)
1211{
1212 unsigned long *d = dst;
1213 int i;
1214
1215 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1216 if (BITS_PER_LONG == 64)
1217 d[i] = cpu_to_le64(src[i]);
1218 else
1219 d[i] = cpu_to_le32(src[i]);
1220 }
1221}
1222EXPORT_SYMBOL(bitmap_copy_le);