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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * lib/bitmap.c
4 * Helper functions for bitmap.h.
5 */
6
7#include <linux/bitmap.h>
8#include <linux/bitops.h>
9#include <linux/ctype.h>
10#include <linux/device.h>
11#include <linux/export.h>
12#include <linux/slab.h>
13
14/**
15 * DOC: bitmap introduction
16 *
17 * bitmaps provide an array of bits, implemented using an
18 * array of unsigned longs. The number of valid bits in a
19 * given bitmap does _not_ need to be an exact multiple of
20 * BITS_PER_LONG.
21 *
22 * The possible unused bits in the last, partially used word
23 * of a bitmap are 'don't care'. The implementation makes
24 * no particular effort to keep them zero. It ensures that
25 * their value will not affect the results of any operation.
26 * The bitmap operations that return Boolean (bitmap_empty,
27 * for example) or scalar (bitmap_weight, for example) results
28 * carefully filter out these unused bits from impacting their
29 * results.
30 *
31 * The byte ordering of bitmaps is more natural on little
32 * endian architectures. See the big-endian headers
33 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
34 * for the best explanations of this ordering.
35 */
36
37bool __bitmap_equal(const unsigned long *bitmap1,
38 const unsigned long *bitmap2, unsigned int bits)
39{
40 unsigned int k, lim = bits/BITS_PER_LONG;
41 for (k = 0; k < lim; ++k)
42 if (bitmap1[k] != bitmap2[k])
43 return false;
44
45 if (bits % BITS_PER_LONG)
46 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
47 return false;
48
49 return true;
50}
51EXPORT_SYMBOL(__bitmap_equal);
52
53bool __bitmap_or_equal(const unsigned long *bitmap1,
54 const unsigned long *bitmap2,
55 const unsigned long *bitmap3,
56 unsigned int bits)
57{
58 unsigned int k, lim = bits / BITS_PER_LONG;
59 unsigned long tmp;
60
61 for (k = 0; k < lim; ++k) {
62 if ((bitmap1[k] | bitmap2[k]) != bitmap3[k])
63 return false;
64 }
65
66 if (!(bits % BITS_PER_LONG))
67 return true;
68
69 tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k];
70 return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0;
71}
72
73void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
74{
75 unsigned int k, lim = BITS_TO_LONGS(bits);
76 for (k = 0; k < lim; ++k)
77 dst[k] = ~src[k];
78}
79EXPORT_SYMBOL(__bitmap_complement);
80
81/**
82 * __bitmap_shift_right - logical right shift of the bits in a bitmap
83 * @dst : destination bitmap
84 * @src : source bitmap
85 * @shift : shift by this many bits
86 * @nbits : bitmap size, in bits
87 *
88 * Shifting right (dividing) means moving bits in the MS -> LS bit
89 * direction. Zeros are fed into the vacated MS positions and the
90 * LS bits shifted off the bottom are lost.
91 */
92void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
93 unsigned shift, unsigned nbits)
94{
95 unsigned k, lim = BITS_TO_LONGS(nbits);
96 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
97 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
98 for (k = 0; off + k < lim; ++k) {
99 unsigned long upper, lower;
100
101 /*
102 * If shift is not word aligned, take lower rem bits of
103 * word above and make them the top rem bits of result.
104 */
105 if (!rem || off + k + 1 >= lim)
106 upper = 0;
107 else {
108 upper = src[off + k + 1];
109 if (off + k + 1 == lim - 1)
110 upper &= mask;
111 upper <<= (BITS_PER_LONG - rem);
112 }
113 lower = src[off + k];
114 if (off + k == lim - 1)
115 lower &= mask;
116 lower >>= rem;
117 dst[k] = lower | upper;
118 }
119 if (off)
120 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
121}
122EXPORT_SYMBOL(__bitmap_shift_right);
123
124
125/**
126 * __bitmap_shift_left - logical left shift of the bits in a bitmap
127 * @dst : destination bitmap
128 * @src : source bitmap
129 * @shift : shift by this many bits
130 * @nbits : bitmap size, in bits
131 *
132 * Shifting left (multiplying) means moving bits in the LS -> MS
133 * direction. Zeros are fed into the vacated LS bit positions
134 * and those MS bits shifted off the top are lost.
135 */
136
137void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
138 unsigned int shift, unsigned int nbits)
139{
140 int k;
141 unsigned int lim = BITS_TO_LONGS(nbits);
142 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
143 for (k = lim - off - 1; k >= 0; --k) {
144 unsigned long upper, lower;
145
146 /*
147 * If shift is not word aligned, take upper rem bits of
148 * word below and make them the bottom rem bits of result.
149 */
150 if (rem && k > 0)
151 lower = src[k - 1] >> (BITS_PER_LONG - rem);
152 else
153 lower = 0;
154 upper = src[k] << rem;
155 dst[k + off] = lower | upper;
156 }
157 if (off)
158 memset(dst, 0, off*sizeof(unsigned long));
159}
160EXPORT_SYMBOL(__bitmap_shift_left);
161
162/**
163 * bitmap_cut() - remove bit region from bitmap and right shift remaining bits
164 * @dst: destination bitmap, might overlap with src
165 * @src: source bitmap
166 * @first: start bit of region to be removed
167 * @cut: number of bits to remove
168 * @nbits: bitmap size, in bits
169 *
170 * Set the n-th bit of @dst iff the n-th bit of @src is set and
171 * n is less than @first, or the m-th bit of @src is set for any
172 * m such that @first <= n < nbits, and m = n + @cut.
173 *
174 * In pictures, example for a big-endian 32-bit architecture:
175 *
176 * The @src bitmap is::
177 *
178 * 31 63
179 * | |
180 * 10000000 11000001 11110010 00010101 10000000 11000001 01110010 00010101
181 * | | | |
182 * 16 14 0 32
183 *
184 * if @cut is 3, and @first is 14, bits 14-16 in @src are cut and @dst is::
185 *
186 * 31 63
187 * | |
188 * 10110000 00011000 00110010 00010101 00010000 00011000 00101110 01000010
189 * | | |
190 * 14 (bit 17 0 32
191 * from @src)
192 *
193 * Note that @dst and @src might overlap partially or entirely.
194 *
195 * This is implemented in the obvious way, with a shift and carry
196 * step for each moved bit. Optimisation is left as an exercise
197 * for the compiler.
198 */
199void bitmap_cut(unsigned long *dst, const unsigned long *src,
200 unsigned int first, unsigned int cut, unsigned int nbits)
201{
202 unsigned int len = BITS_TO_LONGS(nbits);
203 unsigned long keep = 0, carry;
204 int i;
205
206 if (first % BITS_PER_LONG) {
207 keep = src[first / BITS_PER_LONG] &
208 (~0UL >> (BITS_PER_LONG - first % BITS_PER_LONG));
209 }
210
211 memmove(dst, src, len * sizeof(*dst));
212
213 while (cut--) {
214 for (i = first / BITS_PER_LONG; i < len; i++) {
215 if (i < len - 1)
216 carry = dst[i + 1] & 1UL;
217 else
218 carry = 0;
219
220 dst[i] = (dst[i] >> 1) | (carry << (BITS_PER_LONG - 1));
221 }
222 }
223
224 dst[first / BITS_PER_LONG] &= ~0UL << (first % BITS_PER_LONG);
225 dst[first / BITS_PER_LONG] |= keep;
226}
227EXPORT_SYMBOL(bitmap_cut);
228
229bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
230 const unsigned long *bitmap2, unsigned int bits)
231{
232 unsigned int k;
233 unsigned int lim = bits/BITS_PER_LONG;
234 unsigned long result = 0;
235
236 for (k = 0; k < lim; k++)
237 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
238 if (bits % BITS_PER_LONG)
239 result |= (dst[k] = bitmap1[k] & bitmap2[k] &
240 BITMAP_LAST_WORD_MASK(bits));
241 return result != 0;
242}
243EXPORT_SYMBOL(__bitmap_and);
244
245void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
246 const unsigned long *bitmap2, unsigned int bits)
247{
248 unsigned int k;
249 unsigned int nr = BITS_TO_LONGS(bits);
250
251 for (k = 0; k < nr; k++)
252 dst[k] = bitmap1[k] | bitmap2[k];
253}
254EXPORT_SYMBOL(__bitmap_or);
255
256void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
257 const unsigned long *bitmap2, unsigned int bits)
258{
259 unsigned int k;
260 unsigned int nr = BITS_TO_LONGS(bits);
261
262 for (k = 0; k < nr; k++)
263 dst[k] = bitmap1[k] ^ bitmap2[k];
264}
265EXPORT_SYMBOL(__bitmap_xor);
266
267bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
268 const unsigned long *bitmap2, unsigned int bits)
269{
270 unsigned int k;
271 unsigned int lim = bits/BITS_PER_LONG;
272 unsigned long result = 0;
273
274 for (k = 0; k < lim; k++)
275 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
276 if (bits % BITS_PER_LONG)
277 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
278 BITMAP_LAST_WORD_MASK(bits));
279 return result != 0;
280}
281EXPORT_SYMBOL(__bitmap_andnot);
282
283void __bitmap_replace(unsigned long *dst,
284 const unsigned long *old, const unsigned long *new,
285 const unsigned long *mask, unsigned int nbits)
286{
287 unsigned int k;
288 unsigned int nr = BITS_TO_LONGS(nbits);
289
290 for (k = 0; k < nr; k++)
291 dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]);
292}
293EXPORT_SYMBOL(__bitmap_replace);
294
295bool __bitmap_intersects(const unsigned long *bitmap1,
296 const unsigned long *bitmap2, unsigned int bits)
297{
298 unsigned int k, lim = bits/BITS_PER_LONG;
299 for (k = 0; k < lim; ++k)
300 if (bitmap1[k] & bitmap2[k])
301 return true;
302
303 if (bits % BITS_PER_LONG)
304 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
305 return true;
306 return false;
307}
308EXPORT_SYMBOL(__bitmap_intersects);
309
310bool __bitmap_subset(const unsigned long *bitmap1,
311 const unsigned long *bitmap2, unsigned int bits)
312{
313 unsigned int k, lim = bits/BITS_PER_LONG;
314 for (k = 0; k < lim; ++k)
315 if (bitmap1[k] & ~bitmap2[k])
316 return false;
317
318 if (bits % BITS_PER_LONG)
319 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
320 return false;
321 return true;
322}
323EXPORT_SYMBOL(__bitmap_subset);
324
325#define BITMAP_WEIGHT(FETCH, bits) \
326({ \
327 unsigned int __bits = (bits), idx, w = 0; \
328 \
329 for (idx = 0; idx < __bits / BITS_PER_LONG; idx++) \
330 w += hweight_long(FETCH); \
331 \
332 if (__bits % BITS_PER_LONG) \
333 w += hweight_long((FETCH) & BITMAP_LAST_WORD_MASK(__bits)); \
334 \
335 w; \
336})
337
338unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
339{
340 return BITMAP_WEIGHT(bitmap[idx], bits);
341}
342EXPORT_SYMBOL(__bitmap_weight);
343
344unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
345 const unsigned long *bitmap2, unsigned int bits)
346{
347 return BITMAP_WEIGHT(bitmap1[idx] & bitmap2[idx], bits);
348}
349EXPORT_SYMBOL(__bitmap_weight_and);
350
351void __bitmap_set(unsigned long *map, unsigned int start, int len)
352{
353 unsigned long *p = map + BIT_WORD(start);
354 const unsigned int size = start + len;
355 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
356 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
357
358 while (len - bits_to_set >= 0) {
359 *p |= mask_to_set;
360 len -= bits_to_set;
361 bits_to_set = BITS_PER_LONG;
362 mask_to_set = ~0UL;
363 p++;
364 }
365 if (len) {
366 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
367 *p |= mask_to_set;
368 }
369}
370EXPORT_SYMBOL(__bitmap_set);
371
372void __bitmap_clear(unsigned long *map, unsigned int start, int len)
373{
374 unsigned long *p = map + BIT_WORD(start);
375 const unsigned int size = start + len;
376 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
377 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
378
379 while (len - bits_to_clear >= 0) {
380 *p &= ~mask_to_clear;
381 len -= bits_to_clear;
382 bits_to_clear = BITS_PER_LONG;
383 mask_to_clear = ~0UL;
384 p++;
385 }
386 if (len) {
387 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
388 *p &= ~mask_to_clear;
389 }
390}
391EXPORT_SYMBOL(__bitmap_clear);
392
393/**
394 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
395 * @map: The address to base the search on
396 * @size: The bitmap size in bits
397 * @start: The bitnumber to start searching at
398 * @nr: The number of zeroed bits we're looking for
399 * @align_mask: Alignment mask for zero area
400 * @align_offset: Alignment offset for zero area.
401 *
402 * The @align_mask should be one less than a power of 2; the effect is that
403 * the bit offset of all zero areas this function finds plus @align_offset
404 * is multiple of that power of 2.
405 */
406unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
407 unsigned long size,
408 unsigned long start,
409 unsigned int nr,
410 unsigned long align_mask,
411 unsigned long align_offset)
412{
413 unsigned long index, end, i;
414again:
415 index = find_next_zero_bit(map, size, start);
416
417 /* Align allocation */
418 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
419
420 end = index + nr;
421 if (end > size)
422 return end;
423 i = find_next_bit(map, end, index);
424 if (i < end) {
425 start = i + 1;
426 goto again;
427 }
428 return index;
429}
430EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
431
432/**
433 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
434 * @buf: pointer to a bitmap
435 * @pos: a bit position in @buf (0 <= @pos < @nbits)
436 * @nbits: number of valid bit positions in @buf
437 *
438 * Map the bit at position @pos in @buf (of length @nbits) to the
439 * ordinal of which set bit it is. If it is not set or if @pos
440 * is not a valid bit position, map to -1.
441 *
442 * If for example, just bits 4 through 7 are set in @buf, then @pos
443 * values 4 through 7 will get mapped to 0 through 3, respectively,
444 * and other @pos values will get mapped to -1. When @pos value 7
445 * gets mapped to (returns) @ord value 3 in this example, that means
446 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
447 *
448 * The bit positions 0 through @bits are valid positions in @buf.
449 */
450static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
451{
452 if (pos >= nbits || !test_bit(pos, buf))
453 return -1;
454
455 return bitmap_weight(buf, pos);
456}
457
458/**
459 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
460 * @dst: remapped result
461 * @src: subset to be remapped
462 * @old: defines domain of map
463 * @new: defines range of map
464 * @nbits: number of bits in each of these bitmaps
465 *
466 * Let @old and @new define a mapping of bit positions, such that
467 * whatever position is held by the n-th set bit in @old is mapped
468 * to the n-th set bit in @new. In the more general case, allowing
469 * for the possibility that the weight 'w' of @new is less than the
470 * weight of @old, map the position of the n-th set bit in @old to
471 * the position of the m-th set bit in @new, where m == n % w.
472 *
473 * If either of the @old and @new bitmaps are empty, or if @src and
474 * @dst point to the same location, then this routine copies @src
475 * to @dst.
476 *
477 * The positions of unset bits in @old are mapped to themselves
478 * (the identity map).
479 *
480 * Apply the above specified mapping to @src, placing the result in
481 * @dst, clearing any bits previously set in @dst.
482 *
483 * For example, lets say that @old has bits 4 through 7 set, and
484 * @new has bits 12 through 15 set. This defines the mapping of bit
485 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
486 * bit positions unchanged. So if say @src comes into this routine
487 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
488 * 13 and 15 set.
489 */
490void bitmap_remap(unsigned long *dst, const unsigned long *src,
491 const unsigned long *old, const unsigned long *new,
492 unsigned int nbits)
493{
494 unsigned int oldbit, w;
495
496 if (dst == src) /* following doesn't handle inplace remaps */
497 return;
498 bitmap_zero(dst, nbits);
499
500 w = bitmap_weight(new, nbits);
501 for_each_set_bit(oldbit, src, nbits) {
502 int n = bitmap_pos_to_ord(old, oldbit, nbits);
503
504 if (n < 0 || w == 0)
505 set_bit(oldbit, dst); /* identity map */
506 else
507 set_bit(find_nth_bit(new, nbits, n % w), dst);
508 }
509}
510EXPORT_SYMBOL(bitmap_remap);
511
512/**
513 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
514 * @oldbit: bit position to be mapped
515 * @old: defines domain of map
516 * @new: defines range of map
517 * @bits: number of bits in each of these bitmaps
518 *
519 * Let @old and @new define a mapping of bit positions, such that
520 * whatever position is held by the n-th set bit in @old is mapped
521 * to the n-th set bit in @new. In the more general case, allowing
522 * for the possibility that the weight 'w' of @new is less than the
523 * weight of @old, map the position of the n-th set bit in @old to
524 * the position of the m-th set bit in @new, where m == n % w.
525 *
526 * The positions of unset bits in @old are mapped to themselves
527 * (the identity map).
528 *
529 * Apply the above specified mapping to bit position @oldbit, returning
530 * the new bit position.
531 *
532 * For example, lets say that @old has bits 4 through 7 set, and
533 * @new has bits 12 through 15 set. This defines the mapping of bit
534 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
535 * bit positions unchanged. So if say @oldbit is 5, then this routine
536 * returns 13.
537 */
538int bitmap_bitremap(int oldbit, const unsigned long *old,
539 const unsigned long *new, int bits)
540{
541 int w = bitmap_weight(new, bits);
542 int n = bitmap_pos_to_ord(old, oldbit, bits);
543 if (n < 0 || w == 0)
544 return oldbit;
545 else
546 return find_nth_bit(new, bits, n % w);
547}
548EXPORT_SYMBOL(bitmap_bitremap);
549
550#ifdef CONFIG_NUMA
551/**
552 * bitmap_onto - translate one bitmap relative to another
553 * @dst: resulting translated bitmap
554 * @orig: original untranslated bitmap
555 * @relmap: bitmap relative to which translated
556 * @bits: number of bits in each of these bitmaps
557 *
558 * Set the n-th bit of @dst iff there exists some m such that the
559 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
560 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
561 * (If you understood the previous sentence the first time your
562 * read it, you're overqualified for your current job.)
563 *
564 * In other words, @orig is mapped onto (surjectively) @dst,
565 * using the map { <n, m> | the n-th bit of @relmap is the
566 * m-th set bit of @relmap }.
567 *
568 * Any set bits in @orig above bit number W, where W is the
569 * weight of (number of set bits in) @relmap are mapped nowhere.
570 * In particular, if for all bits m set in @orig, m >= W, then
571 * @dst will end up empty. In situations where the possibility
572 * of such an empty result is not desired, one way to avoid it is
573 * to use the bitmap_fold() operator, below, to first fold the
574 * @orig bitmap over itself so that all its set bits x are in the
575 * range 0 <= x < W. The bitmap_fold() operator does this by
576 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
577 *
578 * Example [1] for bitmap_onto():
579 * Let's say @relmap has bits 30-39 set, and @orig has bits
580 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
581 * @dst will have bits 31, 33, 35, 37 and 39 set.
582 *
583 * When bit 0 is set in @orig, it means turn on the bit in
584 * @dst corresponding to whatever is the first bit (if any)
585 * that is turned on in @relmap. Since bit 0 was off in the
586 * above example, we leave off that bit (bit 30) in @dst.
587 *
588 * When bit 1 is set in @orig (as in the above example), it
589 * means turn on the bit in @dst corresponding to whatever
590 * is the second bit that is turned on in @relmap. The second
591 * bit in @relmap that was turned on in the above example was
592 * bit 31, so we turned on bit 31 in @dst.
593 *
594 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
595 * because they were the 4th, 6th, 8th and 10th set bits
596 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
597 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
598 *
599 * When bit 11 is set in @orig, it means turn on the bit in
600 * @dst corresponding to whatever is the twelfth bit that is
601 * turned on in @relmap. In the above example, there were
602 * only ten bits turned on in @relmap (30..39), so that bit
603 * 11 was set in @orig had no affect on @dst.
604 *
605 * Example [2] for bitmap_fold() + bitmap_onto():
606 * Let's say @relmap has these ten bits set::
607 *
608 * 40 41 42 43 45 48 53 61 74 95
609 *
610 * (for the curious, that's 40 plus the first ten terms of the
611 * Fibonacci sequence.)
612 *
613 * Further lets say we use the following code, invoking
614 * bitmap_fold() then bitmap_onto, as suggested above to
615 * avoid the possibility of an empty @dst result::
616 *
617 * unsigned long *tmp; // a temporary bitmap's bits
618 *
619 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
620 * bitmap_onto(dst, tmp, relmap, bits);
621 *
622 * Then this table shows what various values of @dst would be, for
623 * various @orig's. I list the zero-based positions of each set bit.
624 * The tmp column shows the intermediate result, as computed by
625 * using bitmap_fold() to fold the @orig bitmap modulo ten
626 * (the weight of @relmap):
627 *
628 * =============== ============== =================
629 * @orig tmp @dst
630 * 0 0 40
631 * 1 1 41
632 * 9 9 95
633 * 10 0 40 [#f1]_
634 * 1 3 5 7 1 3 5 7 41 43 48 61
635 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
636 * 0 9 18 27 0 9 8 7 40 61 74 95
637 * 0 10 20 30 0 40
638 * 0 11 22 33 0 1 2 3 40 41 42 43
639 * 0 12 24 36 0 2 4 6 40 42 45 53
640 * 78 102 211 1 2 8 41 42 74 [#f1]_
641 * =============== ============== =================
642 *
643 * .. [#f1]
644 *
645 * For these marked lines, if we hadn't first done bitmap_fold()
646 * into tmp, then the @dst result would have been empty.
647 *
648 * If either of @orig or @relmap is empty (no set bits), then @dst
649 * will be returned empty.
650 *
651 * If (as explained above) the only set bits in @orig are in positions
652 * m where m >= W, (where W is the weight of @relmap) then @dst will
653 * once again be returned empty.
654 *
655 * All bits in @dst not set by the above rule are cleared.
656 */
657void bitmap_onto(unsigned long *dst, const unsigned long *orig,
658 const unsigned long *relmap, unsigned int bits)
659{
660 unsigned int n, m; /* same meaning as in above comment */
661
662 if (dst == orig) /* following doesn't handle inplace mappings */
663 return;
664 bitmap_zero(dst, bits);
665
666 /*
667 * The following code is a more efficient, but less
668 * obvious, equivalent to the loop:
669 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
670 * n = find_nth_bit(orig, bits, m);
671 * if (test_bit(m, orig))
672 * set_bit(n, dst);
673 * }
674 */
675
676 m = 0;
677 for_each_set_bit(n, relmap, bits) {
678 /* m == bitmap_pos_to_ord(relmap, n, bits) */
679 if (test_bit(m, orig))
680 set_bit(n, dst);
681 m++;
682 }
683}
684
685/**
686 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
687 * @dst: resulting smaller bitmap
688 * @orig: original larger bitmap
689 * @sz: specified size
690 * @nbits: number of bits in each of these bitmaps
691 *
692 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
693 * Clear all other bits in @dst. See further the comment and
694 * Example [2] for bitmap_onto() for why and how to use this.
695 */
696void bitmap_fold(unsigned long *dst, const unsigned long *orig,
697 unsigned int sz, unsigned int nbits)
698{
699 unsigned int oldbit;
700
701 if (dst == orig) /* following doesn't handle inplace mappings */
702 return;
703 bitmap_zero(dst, nbits);
704
705 for_each_set_bit(oldbit, orig, nbits)
706 set_bit(oldbit % sz, dst);
707}
708#endif /* CONFIG_NUMA */
709
710unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
711{
712 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
713 flags);
714}
715EXPORT_SYMBOL(bitmap_alloc);
716
717unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
718{
719 return bitmap_alloc(nbits, flags | __GFP_ZERO);
720}
721EXPORT_SYMBOL(bitmap_zalloc);
722
723unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node)
724{
725 return kmalloc_array_node(BITS_TO_LONGS(nbits), sizeof(unsigned long),
726 flags, node);
727}
728EXPORT_SYMBOL(bitmap_alloc_node);
729
730unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node)
731{
732 return bitmap_alloc_node(nbits, flags | __GFP_ZERO, node);
733}
734EXPORT_SYMBOL(bitmap_zalloc_node);
735
736void bitmap_free(const unsigned long *bitmap)
737{
738 kfree(bitmap);
739}
740EXPORT_SYMBOL(bitmap_free);
741
742static void devm_bitmap_free(void *data)
743{
744 unsigned long *bitmap = data;
745
746 bitmap_free(bitmap);
747}
748
749unsigned long *devm_bitmap_alloc(struct device *dev,
750 unsigned int nbits, gfp_t flags)
751{
752 unsigned long *bitmap;
753 int ret;
754
755 bitmap = bitmap_alloc(nbits, flags);
756 if (!bitmap)
757 return NULL;
758
759 ret = devm_add_action_or_reset(dev, devm_bitmap_free, bitmap);
760 if (ret)
761 return NULL;
762
763 return bitmap;
764}
765EXPORT_SYMBOL_GPL(devm_bitmap_alloc);
766
767unsigned long *devm_bitmap_zalloc(struct device *dev,
768 unsigned int nbits, gfp_t flags)
769{
770 return devm_bitmap_alloc(dev, nbits, flags | __GFP_ZERO);
771}
772EXPORT_SYMBOL_GPL(devm_bitmap_zalloc);
773
774#if BITS_PER_LONG == 64
775/**
776 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
777 * @bitmap: array of unsigned longs, the destination bitmap
778 * @buf: array of u32 (in host byte order), the source bitmap
779 * @nbits: number of bits in @bitmap
780 */
781void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)
782{
783 unsigned int i, halfwords;
784
785 halfwords = DIV_ROUND_UP(nbits, 32);
786 for (i = 0; i < halfwords; i++) {
787 bitmap[i/2] = (unsigned long) buf[i];
788 if (++i < halfwords)
789 bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
790 }
791
792 /* Clear tail bits in last word beyond nbits. */
793 if (nbits % BITS_PER_LONG)
794 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
795}
796EXPORT_SYMBOL(bitmap_from_arr32);
797
798/**
799 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
800 * @buf: array of u32 (in host byte order), the dest bitmap
801 * @bitmap: array of unsigned longs, the source bitmap
802 * @nbits: number of bits in @bitmap
803 */
804void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
805{
806 unsigned int i, halfwords;
807
808 halfwords = DIV_ROUND_UP(nbits, 32);
809 for (i = 0; i < halfwords; i++) {
810 buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
811 if (++i < halfwords)
812 buf[i] = (u32) (bitmap[i/2] >> 32);
813 }
814
815 /* Clear tail bits in last element of array beyond nbits. */
816 if (nbits % BITS_PER_LONG)
817 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
818}
819EXPORT_SYMBOL(bitmap_to_arr32);
820#endif
821
822#if BITS_PER_LONG == 32
823/**
824 * bitmap_from_arr64 - copy the contents of u64 array of bits to bitmap
825 * @bitmap: array of unsigned longs, the destination bitmap
826 * @buf: array of u64 (in host byte order), the source bitmap
827 * @nbits: number of bits in @bitmap
828 */
829void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits)
830{
831 int n;
832
833 for (n = nbits; n > 0; n -= 64) {
834 u64 val = *buf++;
835
836 *bitmap++ = val;
837 if (n > 32)
838 *bitmap++ = val >> 32;
839 }
840
841 /*
842 * Clear tail bits in the last word beyond nbits.
843 *
844 * Negative index is OK because here we point to the word next
845 * to the last word of the bitmap, except for nbits == 0, which
846 * is tested implicitly.
847 */
848 if (nbits % BITS_PER_LONG)
849 bitmap[-1] &= BITMAP_LAST_WORD_MASK(nbits);
850}
851EXPORT_SYMBOL(bitmap_from_arr64);
852
853/**
854 * bitmap_to_arr64 - copy the contents of bitmap to a u64 array of bits
855 * @buf: array of u64 (in host byte order), the dest bitmap
856 * @bitmap: array of unsigned longs, the source bitmap
857 * @nbits: number of bits in @bitmap
858 */
859void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits)
860{
861 const unsigned long *end = bitmap + BITS_TO_LONGS(nbits);
862
863 while (bitmap < end) {
864 *buf = *bitmap++;
865 if (bitmap < end)
866 *buf |= (u64)(*bitmap++) << 32;
867 buf++;
868 }
869
870 /* Clear tail bits in the last element of array beyond nbits. */
871 if (nbits % 64)
872 buf[-1] &= GENMASK_ULL((nbits - 1) % 64, 0);
873}
874EXPORT_SYMBOL(bitmap_to_arr64);
875#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/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 * DOC: bitmap introduction
23 *
24 * bitmaps provide an array of bits, implemented using an an
25 * array of unsigned longs. The number of valid bits in a
26 * given bitmap does _not_ need to be an exact multiple of
27 * BITS_PER_LONG.
28 *
29 * The possible unused bits in the last, partially used word
30 * of a bitmap are 'don't care'. The implementation makes
31 * no particular effort to keep them zero. It ensures that
32 * their value will not affect the results of any operation.
33 * The bitmap operations that return Boolean (bitmap_empty,
34 * for example) or scalar (bitmap_weight, for example) results
35 * carefully filter out these unused bits from impacting their
36 * results.
37 *
38 * These operations actually hold to a slightly stronger rule:
39 * if you don't input any bitmaps to these ops that have some
40 * unused bits set, then they won't output any set unused bits
41 * in output bitmaps.
42 *
43 * The byte ordering of bitmaps is more natural on little
44 * endian architectures. See the big-endian headers
45 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
46 * for the best explanations of this ordering.
47 */
48
49int __bitmap_equal(const unsigned long *bitmap1,
50 const unsigned long *bitmap2, unsigned int bits)
51{
52 unsigned int k, lim = bits/BITS_PER_LONG;
53 for (k = 0; k < lim; ++k)
54 if (bitmap1[k] != bitmap2[k])
55 return 0;
56
57 if (bits % BITS_PER_LONG)
58 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
59 return 0;
60
61 return 1;
62}
63EXPORT_SYMBOL(__bitmap_equal);
64
65void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
66{
67 unsigned int k, lim = bits/BITS_PER_LONG;
68 for (k = 0; k < lim; ++k)
69 dst[k] = ~src[k];
70
71 if (bits % BITS_PER_LONG)
72 dst[k] = ~src[k];
73}
74EXPORT_SYMBOL(__bitmap_complement);
75
76/**
77 * __bitmap_shift_right - logical right shift of the bits in a bitmap
78 * @dst : destination bitmap
79 * @src : source bitmap
80 * @shift : shift by this many bits
81 * @nbits : bitmap size, in bits
82 *
83 * Shifting right (dividing) means moving bits in the MS -> LS bit
84 * direction. Zeros are fed into the vacated MS positions and the
85 * LS bits shifted off the bottom are lost.
86 */
87void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
88 unsigned shift, unsigned nbits)
89{
90 unsigned k, lim = BITS_TO_LONGS(nbits);
91 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
92 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
93 for (k = 0; off + k < lim; ++k) {
94 unsigned long upper, lower;
95
96 /*
97 * If shift is not word aligned, take lower rem bits of
98 * word above and make them the top rem bits of result.
99 */
100 if (!rem || off + k + 1 >= lim)
101 upper = 0;
102 else {
103 upper = src[off + k + 1];
104 if (off + k + 1 == lim - 1)
105 upper &= mask;
106 upper <<= (BITS_PER_LONG - rem);
107 }
108 lower = src[off + k];
109 if (off + k == lim - 1)
110 lower &= mask;
111 lower >>= rem;
112 dst[k] = lower | upper;
113 }
114 if (off)
115 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
116}
117EXPORT_SYMBOL(__bitmap_shift_right);
118
119
120/**
121 * __bitmap_shift_left - logical left shift of the bits in a bitmap
122 * @dst : destination bitmap
123 * @src : source bitmap
124 * @shift : shift by this many bits
125 * @nbits : bitmap size, in bits
126 *
127 * Shifting left (multiplying) means moving bits in the LS -> MS
128 * direction. Zeros are fed into the vacated LS bit positions
129 * and those MS bits shifted off the top are lost.
130 */
131
132void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
133 unsigned int shift, unsigned int nbits)
134{
135 int k;
136 unsigned int lim = BITS_TO_LONGS(nbits);
137 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
138 for (k = lim - off - 1; k >= 0; --k) {
139 unsigned long upper, lower;
140
141 /*
142 * If shift is not word aligned, take upper rem bits of
143 * word below and make them the bottom rem bits of result.
144 */
145 if (rem && k > 0)
146 lower = src[k - 1] >> (BITS_PER_LONG - rem);
147 else
148 lower = 0;
149 upper = src[k] << rem;
150 dst[k + off] = lower | upper;
151 }
152 if (off)
153 memset(dst, 0, off*sizeof(unsigned long));
154}
155EXPORT_SYMBOL(__bitmap_shift_left);
156
157int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
158 const unsigned long *bitmap2, unsigned int bits)
159{
160 unsigned int k;
161 unsigned int lim = bits/BITS_PER_LONG;
162 unsigned long result = 0;
163
164 for (k = 0; k < lim; k++)
165 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
166 if (bits % BITS_PER_LONG)
167 result |= (dst[k] = bitmap1[k] & bitmap2[k] &
168 BITMAP_LAST_WORD_MASK(bits));
169 return result != 0;
170}
171EXPORT_SYMBOL(__bitmap_and);
172
173void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
174 const unsigned long *bitmap2, unsigned int bits)
175{
176 unsigned int k;
177 unsigned int nr = BITS_TO_LONGS(bits);
178
179 for (k = 0; k < nr; k++)
180 dst[k] = bitmap1[k] | bitmap2[k];
181}
182EXPORT_SYMBOL(__bitmap_or);
183
184void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
185 const unsigned long *bitmap2, unsigned int bits)
186{
187 unsigned int k;
188 unsigned int nr = BITS_TO_LONGS(bits);
189
190 for (k = 0; k < nr; k++)
191 dst[k] = bitmap1[k] ^ bitmap2[k];
192}
193EXPORT_SYMBOL(__bitmap_xor);
194
195int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
196 const unsigned long *bitmap2, unsigned int bits)
197{
198 unsigned int k;
199 unsigned int lim = bits/BITS_PER_LONG;
200 unsigned long result = 0;
201
202 for (k = 0; k < lim; k++)
203 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
204 if (bits % BITS_PER_LONG)
205 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
206 BITMAP_LAST_WORD_MASK(bits));
207 return result != 0;
208}
209EXPORT_SYMBOL(__bitmap_andnot);
210
211int __bitmap_intersects(const unsigned long *bitmap1,
212 const unsigned long *bitmap2, unsigned int bits)
213{
214 unsigned int k, lim = bits/BITS_PER_LONG;
215 for (k = 0; k < lim; ++k)
216 if (bitmap1[k] & bitmap2[k])
217 return 1;
218
219 if (bits % BITS_PER_LONG)
220 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
221 return 1;
222 return 0;
223}
224EXPORT_SYMBOL(__bitmap_intersects);
225
226int __bitmap_subset(const unsigned long *bitmap1,
227 const unsigned long *bitmap2, unsigned int bits)
228{
229 unsigned int k, lim = bits/BITS_PER_LONG;
230 for (k = 0; k < lim; ++k)
231 if (bitmap1[k] & ~bitmap2[k])
232 return 0;
233
234 if (bits % BITS_PER_LONG)
235 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
236 return 0;
237 return 1;
238}
239EXPORT_SYMBOL(__bitmap_subset);
240
241int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
242{
243 unsigned int k, lim = bits/BITS_PER_LONG;
244 int w = 0;
245
246 for (k = 0; k < lim; k++)
247 w += hweight_long(bitmap[k]);
248
249 if (bits % BITS_PER_LONG)
250 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
251
252 return w;
253}
254EXPORT_SYMBOL(__bitmap_weight);
255
256void __bitmap_set(unsigned long *map, unsigned int start, int len)
257{
258 unsigned long *p = map + BIT_WORD(start);
259 const unsigned int size = start + len;
260 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
261 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
262
263 while (len - bits_to_set >= 0) {
264 *p |= mask_to_set;
265 len -= bits_to_set;
266 bits_to_set = BITS_PER_LONG;
267 mask_to_set = ~0UL;
268 p++;
269 }
270 if (len) {
271 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
272 *p |= mask_to_set;
273 }
274}
275EXPORT_SYMBOL(__bitmap_set);
276
277void __bitmap_clear(unsigned long *map, unsigned int start, int len)
278{
279 unsigned long *p = map + BIT_WORD(start);
280 const unsigned int size = start + len;
281 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
282 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
283
284 while (len - bits_to_clear >= 0) {
285 *p &= ~mask_to_clear;
286 len -= bits_to_clear;
287 bits_to_clear = BITS_PER_LONG;
288 mask_to_clear = ~0UL;
289 p++;
290 }
291 if (len) {
292 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
293 *p &= ~mask_to_clear;
294 }
295}
296EXPORT_SYMBOL(__bitmap_clear);
297
298/**
299 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
300 * @map: The address to base the search on
301 * @size: The bitmap size in bits
302 * @start: The bitnumber to start searching at
303 * @nr: The number of zeroed bits we're looking for
304 * @align_mask: Alignment mask for zero area
305 * @align_offset: Alignment offset for zero area.
306 *
307 * The @align_mask should be one less than a power of 2; the effect is that
308 * the bit offset of all zero areas this function finds plus @align_offset
309 * is multiple of that power of 2.
310 */
311unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
312 unsigned long size,
313 unsigned long start,
314 unsigned int nr,
315 unsigned long align_mask,
316 unsigned long align_offset)
317{
318 unsigned long index, end, i;
319again:
320 index = find_next_zero_bit(map, size, start);
321
322 /* Align allocation */
323 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
324
325 end = index + nr;
326 if (end > size)
327 return end;
328 i = find_next_bit(map, end, index);
329 if (i < end) {
330 start = i + 1;
331 goto again;
332 }
333 return index;
334}
335EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
336
337/*
338 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
339 * second version by Paul Jackson, third by Joe Korty.
340 */
341
342#define CHUNKSZ 32
343#define nbits_to_hold_value(val) fls(val)
344#define BASEDEC 10 /* fancier cpuset lists input in decimal */
345
346/**
347 * __bitmap_parse - convert an ASCII hex string into a bitmap.
348 * @buf: pointer to buffer containing string.
349 * @buflen: buffer size in bytes. If string is smaller than this
350 * then it must be terminated with a \0.
351 * @is_user: location of buffer, 0 indicates kernel space
352 * @maskp: pointer to bitmap array that will contain result.
353 * @nmaskbits: size of bitmap, in bits.
354 *
355 * Commas group hex digits into chunks. Each chunk defines exactly 32
356 * bits of the resultant bitmask. No chunk may specify a value larger
357 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
358 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
359 * characters and for grouping errors such as "1,,5", ",44", "," and "".
360 * Leading and trailing whitespace accepted, but not embedded whitespace.
361 */
362int __bitmap_parse(const char *buf, unsigned int buflen,
363 int is_user, unsigned long *maskp,
364 int nmaskbits)
365{
366 int c, old_c, totaldigits, ndigits, nchunks, nbits;
367 u32 chunk;
368 const char __user __force *ubuf = (const char __user __force *)buf;
369
370 bitmap_zero(maskp, nmaskbits);
371
372 nchunks = nbits = totaldigits = c = 0;
373 do {
374 chunk = 0;
375 ndigits = totaldigits;
376
377 /* Get the next chunk of the bitmap */
378 while (buflen) {
379 old_c = c;
380 if (is_user) {
381 if (__get_user(c, ubuf++))
382 return -EFAULT;
383 }
384 else
385 c = *buf++;
386 buflen--;
387 if (isspace(c))
388 continue;
389
390 /*
391 * If the last character was a space and the current
392 * character isn't '\0', we've got embedded whitespace.
393 * This is a no-no, so throw an error.
394 */
395 if (totaldigits && c && isspace(old_c))
396 return -EINVAL;
397
398 /* A '\0' or a ',' signal the end of the chunk */
399 if (c == '\0' || c == ',')
400 break;
401
402 if (!isxdigit(c))
403 return -EINVAL;
404
405 /*
406 * Make sure there are at least 4 free bits in 'chunk'.
407 * If not, this hexdigit will overflow 'chunk', so
408 * throw an error.
409 */
410 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
411 return -EOVERFLOW;
412
413 chunk = (chunk << 4) | hex_to_bin(c);
414 totaldigits++;
415 }
416 if (ndigits == totaldigits)
417 return -EINVAL;
418 if (nchunks == 0 && chunk == 0)
419 continue;
420
421 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
422 *maskp |= chunk;
423 nchunks++;
424 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
425 if (nbits > nmaskbits)
426 return -EOVERFLOW;
427 } while (buflen && c == ',');
428
429 return 0;
430}
431EXPORT_SYMBOL(__bitmap_parse);
432
433/**
434 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
435 *
436 * @ubuf: pointer to user buffer containing string.
437 * @ulen: buffer size in bytes. If string is smaller than this
438 * then it must be terminated with a \0.
439 * @maskp: pointer to bitmap array that will contain result.
440 * @nmaskbits: size of bitmap, in bits.
441 *
442 * Wrapper for __bitmap_parse(), providing it with user buffer.
443 *
444 * We cannot have this as an inline function in bitmap.h because it needs
445 * linux/uaccess.h to get the access_ok() declaration and this causes
446 * cyclic dependencies.
447 */
448int bitmap_parse_user(const char __user *ubuf,
449 unsigned int ulen, unsigned long *maskp,
450 int nmaskbits)
451{
452 if (!access_ok(VERIFY_READ, ubuf, ulen))
453 return -EFAULT;
454 return __bitmap_parse((const char __force *)ubuf,
455 ulen, 1, maskp, nmaskbits);
456
457}
458EXPORT_SYMBOL(bitmap_parse_user);
459
460/**
461 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
462 * @list: indicates whether the bitmap must be list
463 * @buf: page aligned buffer into which string is placed
464 * @maskp: pointer to bitmap to convert
465 * @nmaskbits: size of bitmap, in bits
466 *
467 * Output format is a comma-separated list of decimal numbers and
468 * ranges if list is specified or hex digits grouped into comma-separated
469 * sets of 8 digits/set. Returns the number of characters written to buf.
470 *
471 * It is assumed that @buf is a pointer into a PAGE_SIZE area and that
472 * sufficient storage remains at @buf to accommodate the
473 * bitmap_print_to_pagebuf() output.
474 */
475int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
476 int nmaskbits)
477{
478 ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf;
479 int n = 0;
480
481 if (len > 1)
482 n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
483 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
484 return n;
485}
486EXPORT_SYMBOL(bitmap_print_to_pagebuf);
487
488/**
489 * __bitmap_parselist - convert list format ASCII string to bitmap
490 * @buf: read nul-terminated user string from this buffer
491 * @buflen: buffer size in bytes. If string is smaller than this
492 * then it must be terminated with a \0.
493 * @is_user: location of buffer, 0 indicates kernel space
494 * @maskp: write resulting mask here
495 * @nmaskbits: number of bits in mask to be written
496 *
497 * Input format is a comma-separated list of decimal numbers and
498 * ranges. Consecutively set bits are shown as two hyphen-separated
499 * decimal numbers, the smallest and largest bit numbers set in
500 * the range.
501 * Optionally each range can be postfixed to denote that only parts of it
502 * should be set. The range will divided to groups of specific size.
503 * From each group will be used only defined amount of bits.
504 * Syntax: range:used_size/group_size
505 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
506 *
507 * Returns: 0 on success, -errno on invalid input strings. Error values:
508 *
509 * - ``-EINVAL``: second number in range smaller than first
510 * - ``-EINVAL``: invalid character in string
511 * - ``-ERANGE``: bit number specified too large for mask
512 */
513static int __bitmap_parselist(const char *buf, unsigned int buflen,
514 int is_user, unsigned long *maskp,
515 int nmaskbits)
516{
517 unsigned int a, b, old_a, old_b;
518 unsigned int group_size, used_size, off;
519 int c, old_c, totaldigits, ndigits;
520 const char __user __force *ubuf = (const char __user __force *)buf;
521 int at_start, in_range, in_partial_range;
522
523 totaldigits = c = 0;
524 old_a = old_b = 0;
525 group_size = used_size = 0;
526 bitmap_zero(maskp, nmaskbits);
527 do {
528 at_start = 1;
529 in_range = 0;
530 in_partial_range = 0;
531 a = b = 0;
532 ndigits = totaldigits;
533
534 /* Get the next cpu# or a range of cpu#'s */
535 while (buflen) {
536 old_c = c;
537 if (is_user) {
538 if (__get_user(c, ubuf++))
539 return -EFAULT;
540 } else
541 c = *buf++;
542 buflen--;
543 if (isspace(c))
544 continue;
545
546 /* A '\0' or a ',' signal the end of a cpu# or range */
547 if (c == '\0' || c == ',')
548 break;
549 /*
550 * whitespaces between digits are not allowed,
551 * but it's ok if whitespaces are on head or tail.
552 * when old_c is whilespace,
553 * if totaldigits == ndigits, whitespace is on head.
554 * if whitespace is on tail, it should not run here.
555 * as c was ',' or '\0',
556 * the last code line has broken the current loop.
557 */
558 if ((totaldigits != ndigits) && isspace(old_c))
559 return -EINVAL;
560
561 if (c == '/') {
562 used_size = a;
563 at_start = 1;
564 in_range = 0;
565 a = b = 0;
566 continue;
567 }
568
569 if (c == ':') {
570 old_a = a;
571 old_b = b;
572 at_start = 1;
573 in_range = 0;
574 in_partial_range = 1;
575 a = b = 0;
576 continue;
577 }
578
579 if (c == '-') {
580 if (at_start || in_range)
581 return -EINVAL;
582 b = 0;
583 in_range = 1;
584 at_start = 1;
585 continue;
586 }
587
588 if (!isdigit(c))
589 return -EINVAL;
590
591 b = b * 10 + (c - '0');
592 if (!in_range)
593 a = b;
594 at_start = 0;
595 totaldigits++;
596 }
597 if (ndigits == totaldigits)
598 continue;
599 if (in_partial_range) {
600 group_size = a;
601 a = old_a;
602 b = old_b;
603 old_a = old_b = 0;
604 } else {
605 used_size = group_size = b - a + 1;
606 }
607 /* if no digit is after '-', it's wrong*/
608 if (at_start && in_range)
609 return -EINVAL;
610 if (!(a <= b) || group_size == 0 || !(used_size <= group_size))
611 return -EINVAL;
612 if (b >= nmaskbits)
613 return -ERANGE;
614 while (a <= b) {
615 off = min(b - a + 1, used_size);
616 bitmap_set(maskp, a, off);
617 a += group_size;
618 }
619 } while (buflen && c == ',');
620 return 0;
621}
622
623int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
624{
625 char *nl = strchrnul(bp, '\n');
626 int len = nl - bp;
627
628 return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
629}
630EXPORT_SYMBOL(bitmap_parselist);
631
632
633/**
634 * bitmap_parselist_user()
635 *
636 * @ubuf: pointer to user buffer containing string.
637 * @ulen: buffer size in bytes. If string is smaller than this
638 * then it must be terminated with a \0.
639 * @maskp: pointer to bitmap array that will contain result.
640 * @nmaskbits: size of bitmap, in bits.
641 *
642 * Wrapper for bitmap_parselist(), providing it with user buffer.
643 *
644 * We cannot have this as an inline function in bitmap.h because it needs
645 * linux/uaccess.h to get the access_ok() declaration and this causes
646 * cyclic dependencies.
647 */
648int bitmap_parselist_user(const char __user *ubuf,
649 unsigned int ulen, unsigned long *maskp,
650 int nmaskbits)
651{
652 if (!access_ok(VERIFY_READ, ubuf, ulen))
653 return -EFAULT;
654 return __bitmap_parselist((const char __force *)ubuf,
655 ulen, 1, maskp, nmaskbits);
656}
657EXPORT_SYMBOL(bitmap_parselist_user);
658
659
660/**
661 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
662 * @buf: pointer to a bitmap
663 * @pos: a bit position in @buf (0 <= @pos < @nbits)
664 * @nbits: number of valid bit positions in @buf
665 *
666 * Map the bit at position @pos in @buf (of length @nbits) to the
667 * ordinal of which set bit it is. If it is not set or if @pos
668 * is not a valid bit position, map to -1.
669 *
670 * If for example, just bits 4 through 7 are set in @buf, then @pos
671 * values 4 through 7 will get mapped to 0 through 3, respectively,
672 * and other @pos values will get mapped to -1. When @pos value 7
673 * gets mapped to (returns) @ord value 3 in this example, that means
674 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
675 *
676 * The bit positions 0 through @bits are valid positions in @buf.
677 */
678static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
679{
680 if (pos >= nbits || !test_bit(pos, buf))
681 return -1;
682
683 return __bitmap_weight(buf, pos);
684}
685
686/**
687 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
688 * @buf: pointer to bitmap
689 * @ord: ordinal bit position (n-th set bit, n >= 0)
690 * @nbits: number of valid bit positions in @buf
691 *
692 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
693 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord
694 * >= weight(buf), returns @nbits.
695 *
696 * If for example, just bits 4 through 7 are set in @buf, then @ord
697 * values 0 through 3 will get mapped to 4 through 7, respectively,
698 * and all other @ord values returns @nbits. When @ord value 3
699 * gets mapped to (returns) @pos value 7 in this example, that means
700 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
701 *
702 * The bit positions 0 through @nbits-1 are valid positions in @buf.
703 */
704unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits)
705{
706 unsigned int pos;
707
708 for (pos = find_first_bit(buf, nbits);
709 pos < nbits && ord;
710 pos = find_next_bit(buf, nbits, pos + 1))
711 ord--;
712
713 return pos;
714}
715
716/**
717 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
718 * @dst: remapped result
719 * @src: subset to be remapped
720 * @old: defines domain of map
721 * @new: defines range of map
722 * @nbits: number of bits in each of these bitmaps
723 *
724 * Let @old and @new define a mapping of bit positions, such that
725 * whatever position is held by the n-th set bit in @old is mapped
726 * to the n-th set bit in @new. In the more general case, allowing
727 * for the possibility that the weight 'w' of @new is less than the
728 * weight of @old, map the position of the n-th set bit in @old to
729 * the position of the m-th set bit in @new, where m == n % w.
730 *
731 * If either of the @old and @new bitmaps are empty, or if @src and
732 * @dst point to the same location, then this routine copies @src
733 * to @dst.
734 *
735 * The positions of unset bits in @old are mapped to themselves
736 * (the identify map).
737 *
738 * Apply the above specified mapping to @src, placing the result in
739 * @dst, clearing any bits previously set in @dst.
740 *
741 * For example, lets say that @old has bits 4 through 7 set, and
742 * @new has bits 12 through 15 set. This defines the mapping of bit
743 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
744 * bit positions unchanged. So if say @src comes into this routine
745 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
746 * 13 and 15 set.
747 */
748void bitmap_remap(unsigned long *dst, const unsigned long *src,
749 const unsigned long *old, const unsigned long *new,
750 unsigned int nbits)
751{
752 unsigned int oldbit, w;
753
754 if (dst == src) /* following doesn't handle inplace remaps */
755 return;
756 bitmap_zero(dst, nbits);
757
758 w = bitmap_weight(new, nbits);
759 for_each_set_bit(oldbit, src, nbits) {
760 int n = bitmap_pos_to_ord(old, oldbit, nbits);
761
762 if (n < 0 || w == 0)
763 set_bit(oldbit, dst); /* identity map */
764 else
765 set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst);
766 }
767}
768EXPORT_SYMBOL(bitmap_remap);
769
770/**
771 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
772 * @oldbit: bit position to be mapped
773 * @old: defines domain of map
774 * @new: defines range of map
775 * @bits: number of bits in each of these bitmaps
776 *
777 * Let @old and @new define a mapping of bit positions, such that
778 * whatever position is held by the n-th set bit in @old is mapped
779 * to the n-th set bit in @new. In the more general case, allowing
780 * for the possibility that the weight 'w' of @new is less than the
781 * weight of @old, map the position of the n-th set bit in @old to
782 * the position of the m-th set bit in @new, where m == n % w.
783 *
784 * The positions of unset bits in @old are mapped to themselves
785 * (the identify map).
786 *
787 * Apply the above specified mapping to bit position @oldbit, returning
788 * the new bit position.
789 *
790 * For example, lets say that @old has bits 4 through 7 set, and
791 * @new has bits 12 through 15 set. This defines the mapping of bit
792 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
793 * bit positions unchanged. So if say @oldbit is 5, then this routine
794 * returns 13.
795 */
796int bitmap_bitremap(int oldbit, const unsigned long *old,
797 const unsigned long *new, int bits)
798{
799 int w = bitmap_weight(new, bits);
800 int n = bitmap_pos_to_ord(old, oldbit, bits);
801 if (n < 0 || w == 0)
802 return oldbit;
803 else
804 return bitmap_ord_to_pos(new, n % w, bits);
805}
806EXPORT_SYMBOL(bitmap_bitremap);
807
808/**
809 * bitmap_onto - translate one bitmap relative to another
810 * @dst: resulting translated bitmap
811 * @orig: original untranslated bitmap
812 * @relmap: bitmap relative to which translated
813 * @bits: number of bits in each of these bitmaps
814 *
815 * Set the n-th bit of @dst iff there exists some m such that the
816 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
817 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
818 * (If you understood the previous sentence the first time your
819 * read it, you're overqualified for your current job.)
820 *
821 * In other words, @orig is mapped onto (surjectively) @dst,
822 * using the map { <n, m> | the n-th bit of @relmap is the
823 * m-th set bit of @relmap }.
824 *
825 * Any set bits in @orig above bit number W, where W is the
826 * weight of (number of set bits in) @relmap are mapped nowhere.
827 * In particular, if for all bits m set in @orig, m >= W, then
828 * @dst will end up empty. In situations where the possibility
829 * of such an empty result is not desired, one way to avoid it is
830 * to use the bitmap_fold() operator, below, to first fold the
831 * @orig bitmap over itself so that all its set bits x are in the
832 * range 0 <= x < W. The bitmap_fold() operator does this by
833 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
834 *
835 * Example [1] for bitmap_onto():
836 * Let's say @relmap has bits 30-39 set, and @orig has bits
837 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
838 * @dst will have bits 31, 33, 35, 37 and 39 set.
839 *
840 * When bit 0 is set in @orig, it means turn on the bit in
841 * @dst corresponding to whatever is the first bit (if any)
842 * that is turned on in @relmap. Since bit 0 was off in the
843 * above example, we leave off that bit (bit 30) in @dst.
844 *
845 * When bit 1 is set in @orig (as in the above example), it
846 * means turn on the bit in @dst corresponding to whatever
847 * is the second bit that is turned on in @relmap. The second
848 * bit in @relmap that was turned on in the above example was
849 * bit 31, so we turned on bit 31 in @dst.
850 *
851 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
852 * because they were the 4th, 6th, 8th and 10th set bits
853 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
854 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
855 *
856 * When bit 11 is set in @orig, it means turn on the bit in
857 * @dst corresponding to whatever is the twelfth bit that is
858 * turned on in @relmap. In the above example, there were
859 * only ten bits turned on in @relmap (30..39), so that bit
860 * 11 was set in @orig had no affect on @dst.
861 *
862 * Example [2] for bitmap_fold() + bitmap_onto():
863 * Let's say @relmap has these ten bits set::
864 *
865 * 40 41 42 43 45 48 53 61 74 95
866 *
867 * (for the curious, that's 40 plus the first ten terms of the
868 * Fibonacci sequence.)
869 *
870 * Further lets say we use the following code, invoking
871 * bitmap_fold() then bitmap_onto, as suggested above to
872 * avoid the possibility of an empty @dst result::
873 *
874 * unsigned long *tmp; // a temporary bitmap's bits
875 *
876 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
877 * bitmap_onto(dst, tmp, relmap, bits);
878 *
879 * Then this table shows what various values of @dst would be, for
880 * various @orig's. I list the zero-based positions of each set bit.
881 * The tmp column shows the intermediate result, as computed by
882 * using bitmap_fold() to fold the @orig bitmap modulo ten
883 * (the weight of @relmap):
884 *
885 * =============== ============== =================
886 * @orig tmp @dst
887 * 0 0 40
888 * 1 1 41
889 * 9 9 95
890 * 10 0 40 [#f1]_
891 * 1 3 5 7 1 3 5 7 41 43 48 61
892 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
893 * 0 9 18 27 0 9 8 7 40 61 74 95
894 * 0 10 20 30 0 40
895 * 0 11 22 33 0 1 2 3 40 41 42 43
896 * 0 12 24 36 0 2 4 6 40 42 45 53
897 * 78 102 211 1 2 8 41 42 74 [#f1]_
898 * =============== ============== =================
899 *
900 * .. [#f1]
901 *
902 * For these marked lines, if we hadn't first done bitmap_fold()
903 * into tmp, then the @dst result would have been empty.
904 *
905 * If either of @orig or @relmap is empty (no set bits), then @dst
906 * will be returned empty.
907 *
908 * If (as explained above) the only set bits in @orig are in positions
909 * m where m >= W, (where W is the weight of @relmap) then @dst will
910 * once again be returned empty.
911 *
912 * All bits in @dst not set by the above rule are cleared.
913 */
914void bitmap_onto(unsigned long *dst, const unsigned long *orig,
915 const unsigned long *relmap, unsigned int bits)
916{
917 unsigned int n, m; /* same meaning as in above comment */
918
919 if (dst == orig) /* following doesn't handle inplace mappings */
920 return;
921 bitmap_zero(dst, bits);
922
923 /*
924 * The following code is a more efficient, but less
925 * obvious, equivalent to the loop:
926 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
927 * n = bitmap_ord_to_pos(orig, m, bits);
928 * if (test_bit(m, orig))
929 * set_bit(n, dst);
930 * }
931 */
932
933 m = 0;
934 for_each_set_bit(n, relmap, bits) {
935 /* m == bitmap_pos_to_ord(relmap, n, bits) */
936 if (test_bit(m, orig))
937 set_bit(n, dst);
938 m++;
939 }
940}
941EXPORT_SYMBOL(bitmap_onto);
942
943/**
944 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
945 * @dst: resulting smaller bitmap
946 * @orig: original larger bitmap
947 * @sz: specified size
948 * @nbits: number of bits in each of these bitmaps
949 *
950 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
951 * Clear all other bits in @dst. See further the comment and
952 * Example [2] for bitmap_onto() for why and how to use this.
953 */
954void bitmap_fold(unsigned long *dst, const unsigned long *orig,
955 unsigned int sz, unsigned int nbits)
956{
957 unsigned int oldbit;
958
959 if (dst == orig) /* following doesn't handle inplace mappings */
960 return;
961 bitmap_zero(dst, nbits);
962
963 for_each_set_bit(oldbit, orig, nbits)
964 set_bit(oldbit % sz, dst);
965}
966EXPORT_SYMBOL(bitmap_fold);
967
968/*
969 * Common code for bitmap_*_region() routines.
970 * bitmap: array of unsigned longs corresponding to the bitmap
971 * pos: the beginning of the region
972 * order: region size (log base 2 of number of bits)
973 * reg_op: operation(s) to perform on that region of bitmap
974 *
975 * Can set, verify and/or release a region of bits in a bitmap,
976 * depending on which combination of REG_OP_* flag bits is set.
977 *
978 * A region of a bitmap is a sequence of bits in the bitmap, of
979 * some size '1 << order' (a power of two), aligned to that same
980 * '1 << order' power of two.
981 *
982 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
983 * Returns 0 in all other cases and reg_ops.
984 */
985
986enum {
987 REG_OP_ISFREE, /* true if region is all zero bits */
988 REG_OP_ALLOC, /* set all bits in region */
989 REG_OP_RELEASE, /* clear all bits in region */
990};
991
992static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
993{
994 int nbits_reg; /* number of bits in region */
995 int index; /* index first long of region in bitmap */
996 int offset; /* bit offset region in bitmap[index] */
997 int nlongs_reg; /* num longs spanned by region in bitmap */
998 int nbitsinlong; /* num bits of region in each spanned long */
999 unsigned long mask; /* bitmask for one long of region */
1000 int i; /* scans bitmap by longs */
1001 int ret = 0; /* return value */
1002
1003 /*
1004 * Either nlongs_reg == 1 (for small orders that fit in one long)
1005 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1006 */
1007 nbits_reg = 1 << order;
1008 index = pos / BITS_PER_LONG;
1009 offset = pos - (index * BITS_PER_LONG);
1010 nlongs_reg = BITS_TO_LONGS(nbits_reg);
1011 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1012
1013 /*
1014 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1015 * overflows if nbitsinlong == BITS_PER_LONG.
1016 */
1017 mask = (1UL << (nbitsinlong - 1));
1018 mask += mask - 1;
1019 mask <<= offset;
1020
1021 switch (reg_op) {
1022 case REG_OP_ISFREE:
1023 for (i = 0; i < nlongs_reg; i++) {
1024 if (bitmap[index + i] & mask)
1025 goto done;
1026 }
1027 ret = 1; /* all bits in region free (zero) */
1028 break;
1029
1030 case REG_OP_ALLOC:
1031 for (i = 0; i < nlongs_reg; i++)
1032 bitmap[index + i] |= mask;
1033 break;
1034
1035 case REG_OP_RELEASE:
1036 for (i = 0; i < nlongs_reg; i++)
1037 bitmap[index + i] &= ~mask;
1038 break;
1039 }
1040done:
1041 return ret;
1042}
1043
1044/**
1045 * bitmap_find_free_region - find a contiguous aligned mem region
1046 * @bitmap: array of unsigned longs corresponding to the bitmap
1047 * @bits: number of bits in the bitmap
1048 * @order: region size (log base 2 of number of bits) to find
1049 *
1050 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1051 * allocate them (set them to one). Only consider regions of length
1052 * a power (@order) of two, aligned to that power of two, which
1053 * makes the search algorithm much faster.
1054 *
1055 * Return the bit offset in bitmap of the allocated region,
1056 * or -errno on failure.
1057 */
1058int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
1059{
1060 unsigned int pos, end; /* scans bitmap by regions of size order */
1061
1062 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
1063 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1064 continue;
1065 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1066 return pos;
1067 }
1068 return -ENOMEM;
1069}
1070EXPORT_SYMBOL(bitmap_find_free_region);
1071
1072/**
1073 * bitmap_release_region - release allocated bitmap region
1074 * @bitmap: array of unsigned longs corresponding to the bitmap
1075 * @pos: beginning of bit region to release
1076 * @order: region size (log base 2 of number of bits) to release
1077 *
1078 * This is the complement to __bitmap_find_free_region() and releases
1079 * the found region (by clearing it in the bitmap).
1080 *
1081 * No return value.
1082 */
1083void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
1084{
1085 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1086}
1087EXPORT_SYMBOL(bitmap_release_region);
1088
1089/**
1090 * bitmap_allocate_region - allocate bitmap region
1091 * @bitmap: array of unsigned longs corresponding to the bitmap
1092 * @pos: beginning of bit region to allocate
1093 * @order: region size (log base 2 of number of bits) to allocate
1094 *
1095 * Allocate (set bits in) a specified region of a bitmap.
1096 *
1097 * Return 0 on success, or %-EBUSY if specified region wasn't
1098 * free (not all bits were zero).
1099 */
1100int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
1101{
1102 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1103 return -EBUSY;
1104 return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1105}
1106EXPORT_SYMBOL(bitmap_allocate_region);
1107
1108/**
1109 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1110 * @dst: destination buffer
1111 * @src: bitmap to copy
1112 * @nbits: number of bits in the bitmap
1113 *
1114 * Require nbits % BITS_PER_LONG == 0.
1115 */
1116#ifdef __BIG_ENDIAN
1117void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
1118{
1119 unsigned int i;
1120
1121 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1122 if (BITS_PER_LONG == 64)
1123 dst[i] = cpu_to_le64(src[i]);
1124 else
1125 dst[i] = cpu_to_le32(src[i]);
1126 }
1127}
1128EXPORT_SYMBOL(bitmap_copy_le);
1129#endif
1130
1131#if BITS_PER_LONG == 64
1132/**
1133 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
1134 * @bitmap: array of unsigned longs, the destination bitmap
1135 * @buf: array of u32 (in host byte order), the source bitmap
1136 * @nbits: number of bits in @bitmap
1137 */
1138void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,
1139 unsigned int nbits)
1140{
1141 unsigned int i, halfwords;
1142
1143 if (!nbits)
1144 return;
1145
1146 halfwords = DIV_ROUND_UP(nbits, 32);
1147 for (i = 0; i < halfwords; i++) {
1148 bitmap[i/2] = (unsigned long) buf[i];
1149 if (++i < halfwords)
1150 bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
1151 }
1152
1153 /* Clear tail bits in last word beyond nbits. */
1154 if (nbits % BITS_PER_LONG)
1155 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
1156}
1157EXPORT_SYMBOL(bitmap_from_arr32);
1158
1159/**
1160 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
1161 * @buf: array of u32 (in host byte order), the dest bitmap
1162 * @bitmap: array of unsigned longs, the source bitmap
1163 * @nbits: number of bits in @bitmap
1164 */
1165void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
1166{
1167 unsigned int i, halfwords;
1168
1169 if (!nbits)
1170 return;
1171
1172 halfwords = DIV_ROUND_UP(nbits, 32);
1173 for (i = 0; i < halfwords; i++) {
1174 buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
1175 if (++i < halfwords)
1176 buf[i] = (u32) (bitmap[i/2] >> 32);
1177 }
1178
1179 /* Clear tail bits in last element of array beyond nbits. */
1180 if (nbits % BITS_PER_LONG)
1181 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
1182}
1183EXPORT_SYMBOL(bitmap_to_arr32);
1184
1185#endif