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