1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __LINUX_BITMAP_H
3#define __LINUX_BITMAP_H
4
5#ifndef __ASSEMBLY__
6
7#include <linux/align.h>
8#include <linux/bitops.h>
9#include <linux/cleanup.h>
10#include <linux/errno.h>
11#include <linux/find.h>
12#include <linux/limits.h>
13#include <linux/string.h>
14#include <linux/types.h>
15#include <linux/bitmap-str.h>
16
17struct device;
18
19/*
20 * bitmaps provide bit arrays that consume one or more unsigned
21 * longs. The bitmap interface and available operations are listed
22 * here, in bitmap.h
23 *
24 * Function implementations generic to all architectures are in
25 * lib/bitmap.c. Functions implementations that are architecture
26 * specific are in various arch/<arch>/include/asm/bitops.h headers
27 * and other arch/<arch> specific files.
28 *
29 * See lib/bitmap.c for more details.
30 */
31
32/**
33 * DOC: bitmap overview
34 *
35 * The available bitmap operations and their rough meaning in the
36 * case that the bitmap is a single unsigned long are thus:
37 *
38 * The generated code is more efficient when nbits is known at
39 * compile-time and at most BITS_PER_LONG.
40 *
41 * ::
42 *
43 * bitmap_zero(dst, nbits) *dst = 0UL
44 * bitmap_fill(dst, nbits) *dst = ~0UL
45 * bitmap_copy(dst, src, nbits) *dst = *src
46 * bitmap_and(dst, src1, src2, nbits) *dst = *src1 & *src2
47 * bitmap_or(dst, src1, src2, nbits) *dst = *src1 | *src2
48 * bitmap_xor(dst, src1, src2, nbits) *dst = *src1 ^ *src2
49 * bitmap_andnot(dst, src1, src2, nbits) *dst = *src1 & ~(*src2)
50 * bitmap_complement(dst, src, nbits) *dst = ~(*src)
51 * bitmap_equal(src1, src2, nbits) Are *src1 and *src2 equal?
52 * bitmap_intersects(src1, src2, nbits) Do *src1 and *src2 overlap?
53 * bitmap_subset(src1, src2, nbits) Is *src1 a subset of *src2?
54 * bitmap_empty(src, nbits) Are all bits zero in *src?
55 * bitmap_full(src, nbits) Are all bits set in *src?
56 * bitmap_weight(src, nbits) Hamming Weight: number set bits
57 * bitmap_weight_and(src1, src2, nbits) Hamming Weight of and'ed bitmap
58 * bitmap_weight_andnot(src1, src2, nbits) Hamming Weight of andnot'ed bitmap
59 * bitmap_set(dst, pos, nbits) Set specified bit area
60 * bitmap_clear(dst, pos, nbits) Clear specified bit area
61 * bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area
62 * bitmap_find_next_zero_area_off(buf, len, pos, n, mask, mask_off) as above
63 * bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n
64 * bitmap_shift_left(dst, src, n, nbits) *dst = *src << n
65 * bitmap_cut(dst, src, first, n, nbits) Cut n bits from first, copy rest
66 * bitmap_replace(dst, old, new, mask, nbits) *dst = (*old & ~(*mask)) | (*new & *mask)
67 * bitmap_scatter(dst, src, mask, nbits) *dst = map(dense, sparse)(src)
68 * bitmap_gather(dst, src, mask, nbits) *dst = map(sparse, dense)(src)
69 * bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src)
70 * bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit)
71 * bitmap_onto(dst, orig, relmap, nbits) *dst = orig relative to relmap
72 * bitmap_fold(dst, orig, sz, nbits) dst bits = orig bits mod sz
73 * bitmap_parse(buf, buflen, dst, nbits) Parse bitmap dst from kernel buf
74 * bitmap_parse_user(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf
75 * bitmap_parselist(buf, dst, nbits) Parse bitmap dst from kernel buf
76 * bitmap_parselist_user(buf, dst, nbits) Parse bitmap dst from user buf
77 * bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region
78 * bitmap_release_region(bitmap, pos, order) Free specified bit region
79 * bitmap_allocate_region(bitmap, pos, order) Allocate specified bit region
80 * bitmap_from_arr32(dst, buf, nbits) Copy nbits from u32[] buf to dst
81 * bitmap_from_arr64(dst, buf, nbits) Copy nbits from u64[] buf to dst
82 * bitmap_to_arr32(buf, src, nbits) Copy nbits from buf to u32[] dst
83 * bitmap_to_arr64(buf, src, nbits) Copy nbits from buf to u64[] dst
84 * bitmap_get_value8(map, start) Get 8bit value from map at start
85 * bitmap_set_value8(map, value, start) Set 8bit value to map at start
86 * bitmap_read(map, start, nbits) Read an nbits-sized value from
87 * map at start
88 * bitmap_write(map, value, start, nbits) Write an nbits-sized value to
89 * map at start
90 *
91 * Note, bitmap_zero() and bitmap_fill() operate over the region of
92 * unsigned longs, that is, bits behind bitmap till the unsigned long
93 * boundary will be zeroed or filled as well. Consider to use
94 * bitmap_clear() or bitmap_set() to make explicit zeroing or filling
95 * respectively.
96 */
97
98/**
99 * DOC: bitmap bitops
100 *
101 * Also the following operations in asm/bitops.h apply to bitmaps.::
102 *
103 * set_bit(bit, addr) *addr |= bit
104 * clear_bit(bit, addr) *addr &= ~bit
105 * change_bit(bit, addr) *addr ^= bit
106 * test_bit(bit, addr) Is bit set in *addr?
107 * test_and_set_bit(bit, addr) Set bit and return old value
108 * test_and_clear_bit(bit, addr) Clear bit and return old value
109 * test_and_change_bit(bit, addr) Change bit and return old value
110 * find_first_zero_bit(addr, nbits) Position first zero bit in *addr
111 * find_first_bit(addr, nbits) Position first set bit in *addr
112 * find_next_zero_bit(addr, nbits, bit)
113 * Position next zero bit in *addr >= bit
114 * find_next_bit(addr, nbits, bit) Position next set bit in *addr >= bit
115 * find_next_and_bit(addr1, addr2, nbits, bit)
116 * Same as find_next_bit, but in
117 * (*addr1 & *addr2)
118 *
119 */
120
121/**
122 * DOC: declare bitmap
123 * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
124 * to declare an array named 'name' of just enough unsigned longs to
125 * contain all bit positions from 0 to 'bits' - 1.
126 */
127
128/*
129 * Allocation and deallocation of bitmap.
130 * Provided in lib/bitmap.c to avoid circular dependency.
131 */
132unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
133unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
134unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node);
135unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node);
136void bitmap_free(const unsigned long *bitmap);
137
138DEFINE_FREE(bitmap, unsigned long *, if (_T) bitmap_free(_T))
139
140/* Managed variants of the above. */
141unsigned long *devm_bitmap_alloc(struct device *dev,
142 unsigned int nbits, gfp_t flags);
143unsigned long *devm_bitmap_zalloc(struct device *dev,
144 unsigned int nbits, gfp_t flags);
145
146/*
147 * lib/bitmap.c provides these functions:
148 */
149
150bool __bitmap_equal(const unsigned long *bitmap1,
151 const unsigned long *bitmap2, unsigned int nbits);
152bool __pure __bitmap_or_equal(const unsigned long *src1,
153 const unsigned long *src2,
154 const unsigned long *src3,
155 unsigned int nbits);
156void __bitmap_complement(unsigned long *dst, const unsigned long *src,
157 unsigned int nbits);
158void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
159 unsigned int shift, unsigned int nbits);
160void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
161 unsigned int shift, unsigned int nbits);
162void bitmap_cut(unsigned long *dst, const unsigned long *src,
163 unsigned int first, unsigned int cut, unsigned int nbits);
164bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
165 const unsigned long *bitmap2, unsigned int nbits);
166void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
167 const unsigned long *bitmap2, unsigned int nbits);
168void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
169 const unsigned long *bitmap2, unsigned int nbits);
170bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
171 const unsigned long *bitmap2, unsigned int nbits);
172void __bitmap_replace(unsigned long *dst,
173 const unsigned long *old, const unsigned long *new,
174 const unsigned long *mask, unsigned int nbits);
175bool __bitmap_intersects(const unsigned long *bitmap1,
176 const unsigned long *bitmap2, unsigned int nbits);
177bool __bitmap_subset(const unsigned long *bitmap1,
178 const unsigned long *bitmap2, unsigned int nbits);
179unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
180unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
181 const unsigned long *bitmap2, unsigned int nbits);
182unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1,
183 const unsigned long *bitmap2, unsigned int nbits);
184void __bitmap_set(unsigned long *map, unsigned int start, int len);
185void __bitmap_clear(unsigned long *map, unsigned int start, int len);
186
187unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
188 unsigned long size,
189 unsigned long start,
190 unsigned int nr,
191 unsigned long align_mask,
192 unsigned long align_offset);
193
194/**
195 * bitmap_find_next_zero_area - find a contiguous aligned zero area
196 * @map: The address to base the search on
197 * @size: The bitmap size in bits
198 * @start: The bitnumber to start searching at
199 * @nr: The number of zeroed bits we're looking for
200 * @align_mask: Alignment mask for zero area
201 *
202 * The @align_mask should be one less than a power of 2; the effect is that
203 * the bit offset of all zero areas this function finds is multiples of that
204 * power of 2. A @align_mask of 0 means no alignment is required.
205 */
206static __always_inline
207unsigned long bitmap_find_next_zero_area(unsigned long *map,
208 unsigned long size,
209 unsigned long start,
210 unsigned int nr,
211 unsigned long align_mask)
212{
213 return bitmap_find_next_zero_area_off(map, size, start, nr,
214 align_mask, align_offset: 0);
215}
216
217void bitmap_remap(unsigned long *dst, const unsigned long *src,
218 const unsigned long *old, const unsigned long *new, unsigned int nbits);
219int bitmap_bitremap(int oldbit,
220 const unsigned long *old, const unsigned long *new, int bits);
221void bitmap_onto(unsigned long *dst, const unsigned long *orig,
222 const unsigned long *relmap, unsigned int bits);
223void bitmap_fold(unsigned long *dst, const unsigned long *orig,
224 unsigned int sz, unsigned int nbits);
225
226#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
227#define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
228
229#define bitmap_size(nbits) (ALIGN(nbits, BITS_PER_LONG) / BITS_PER_BYTE)
230
231static __always_inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
232{
233 unsigned int len = bitmap_size(nbits);
234
235 if (small_const_nbits(nbits))
236 *dst = 0;
237 else
238 memset(dst, 0, len);
239}
240
241static __always_inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
242{
243 unsigned int len = bitmap_size(nbits);
244
245 if (small_const_nbits(nbits))
246 *dst = ~0UL;
247 else
248 memset(dst, 0xff, len);
249}
250
251static __always_inline
252void bitmap_copy(unsigned long *dst, const unsigned long *src, unsigned int nbits)
253{
254 unsigned int len = bitmap_size(nbits);
255
256 if (small_const_nbits(nbits))
257 *dst = *src;
258 else
259 memcpy(dst, src, len);
260}
261
262/*
263 * Copy bitmap and clear tail bits in last word.
264 */
265static __always_inline
266void bitmap_copy_clear_tail(unsigned long *dst, const unsigned long *src, unsigned int nbits)
267{
268 bitmap_copy(dst, src, nbits);
269 if (nbits % BITS_PER_LONG)
270 dst[nbits / BITS_PER_LONG] &= BITMAP_LAST_WORD_MASK(nbits);
271}
272
273static inline void bitmap_copy_and_extend(unsigned long *to,
274 const unsigned long *from,
275 unsigned int count, unsigned int size)
276{
277 unsigned int copy = BITS_TO_LONGS(count);
278
279 memcpy(to, from, copy * sizeof(long));
280 if (count % BITS_PER_LONG)
281 to[copy - 1] &= BITMAP_LAST_WORD_MASK(count);
282 memset(to + copy, 0, bitmap_size(size) - copy * sizeof(long));
283}
284
285/*
286 * On 32-bit systems bitmaps are represented as u32 arrays internally. On LE64
287 * machines the order of hi and lo parts of numbers match the bitmap structure.
288 * In both cases conversion is not needed when copying data from/to arrays of
289 * u32. But in LE64 case, typecast in bitmap_copy_clear_tail() may lead
290 * to out-of-bound access. To avoid that, both LE and BE variants of 64-bit
291 * architectures are not using bitmap_copy_clear_tail().
292 */
293#if BITS_PER_LONG == 64
294void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,
295 unsigned int nbits);
296void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,
297 unsigned int nbits);
298#else
299#define bitmap_from_arr32(bitmap, buf, nbits) \
300 bitmap_copy_clear_tail((unsigned long *) (bitmap), \
301 (const unsigned long *) (buf), (nbits))
302#define bitmap_to_arr32(buf, bitmap, nbits) \
303 bitmap_copy_clear_tail((unsigned long *) (buf), \
304 (const unsigned long *) (bitmap), (nbits))
305#endif
306
307/*
308 * On 64-bit systems bitmaps are represented as u64 arrays internally. So,
309 * the conversion is not needed when copying data from/to arrays of u64.
310 */
311#if BITS_PER_LONG == 32
312void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits);
313void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits);
314#else
315#define bitmap_from_arr64(bitmap, buf, nbits) \
316 bitmap_copy_clear_tail((unsigned long *)(bitmap), (const unsigned long *)(buf), (nbits))
317#define bitmap_to_arr64(buf, bitmap, nbits) \
318 bitmap_copy_clear_tail((unsigned long *)(buf), (const unsigned long *)(bitmap), (nbits))
319#endif
320
321static __always_inline
322bool bitmap_and(unsigned long *dst, const unsigned long *src1,
323 const unsigned long *src2, unsigned int nbits)
324{
325 if (small_const_nbits(nbits))
326 return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
327 return __bitmap_and(dst, bitmap1: src1, bitmap2: src2, nbits);
328}
329
330static __always_inline
331void bitmap_or(unsigned long *dst, const unsigned long *src1,
332 const unsigned long *src2, unsigned int nbits)
333{
334 if (small_const_nbits(nbits))
335 *dst = *src1 | *src2;
336 else
337 __bitmap_or(dst, bitmap1: src1, bitmap2: src2, nbits);
338}
339
340static __always_inline
341void bitmap_xor(unsigned long *dst, const unsigned long *src1,
342 const unsigned long *src2, unsigned int nbits)
343{
344 if (small_const_nbits(nbits))
345 *dst = *src1 ^ *src2;
346 else
347 __bitmap_xor(dst, bitmap1: src1, bitmap2: src2, nbits);
348}
349
350static __always_inline
351bool bitmap_andnot(unsigned long *dst, const unsigned long *src1,
352 const unsigned long *src2, unsigned int nbits)
353{
354 if (small_const_nbits(nbits))
355 return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
356 return __bitmap_andnot(dst, bitmap1: src1, bitmap2: src2, nbits);
357}
358
359static __always_inline
360void bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int nbits)
361{
362 if (small_const_nbits(nbits))
363 *dst = ~(*src);
364 else
365 __bitmap_complement(dst, src, nbits);
366}
367
368#ifdef __LITTLE_ENDIAN
369#define BITMAP_MEM_ALIGNMENT 8
370#else
371#define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
372#endif
373#define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)
374
375static __always_inline
376bool bitmap_equal(const unsigned long *src1, const unsigned long *src2, unsigned int nbits)
377{
378 if (small_const_nbits(nbits))
379 return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
380 if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
381 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
382 return !memcmp(p: src1, q: src2, size: nbits / 8);
383 return __bitmap_equal(bitmap1: src1, bitmap2: src2, nbits);
384}
385
386/**
387 * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third
388 * @src1: Pointer to bitmap 1
389 * @src2: Pointer to bitmap 2 will be or'ed with bitmap 1
390 * @src3: Pointer to bitmap 3. Compare to the result of *@src1 | *@src2
391 * @nbits: number of bits in each of these bitmaps
392 *
393 * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
394 */
395static __always_inline
396bool bitmap_or_equal(const unsigned long *src1, const unsigned long *src2,
397 const unsigned long *src3, unsigned int nbits)
398{
399 if (!small_const_nbits(nbits))
400 return __bitmap_or_equal(src1, src2, src3, nbits);
401
402 return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
403}
404
405static __always_inline
406bool bitmap_intersects(const unsigned long *src1, const unsigned long *src2, unsigned int nbits)
407{
408 if (small_const_nbits(nbits))
409 return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
410 else
411 return __bitmap_intersects(bitmap1: src1, bitmap2: src2, nbits);
412}
413
414static __always_inline
415bool bitmap_subset(const unsigned long *src1, const unsigned long *src2, unsigned int nbits)
416{
417 if (small_const_nbits(nbits))
418 return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
419 else
420 return __bitmap_subset(bitmap1: src1, bitmap2: src2, nbits);
421}
422
423static __always_inline
424bool bitmap_empty(const unsigned long *src, unsigned nbits)
425{
426 if (small_const_nbits(nbits))
427 return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
428
429 return find_first_bit(addr: src, size: nbits) == nbits;
430}
431
432static __always_inline
433bool bitmap_full(const unsigned long *src, unsigned int nbits)
434{
435 if (small_const_nbits(nbits))
436 return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
437
438 return find_first_zero_bit(addr: src, size: nbits) == nbits;
439}
440
441static __always_inline
442unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits)
443{
444 if (small_const_nbits(nbits))
445 return hweight_long(w: *src & BITMAP_LAST_WORD_MASK(nbits));
446 return __bitmap_weight(bitmap: src, nbits);
447}
448
449static __always_inline
450unsigned long bitmap_weight_and(const unsigned long *src1,
451 const unsigned long *src2, unsigned int nbits)
452{
453 if (small_const_nbits(nbits))
454 return hweight_long(w: *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits));
455 return __bitmap_weight_and(bitmap1: src1, bitmap2: src2, nbits);
456}
457
458static __always_inline
459unsigned long bitmap_weight_andnot(const unsigned long *src1,
460 const unsigned long *src2, unsigned int nbits)
461{
462 if (small_const_nbits(nbits))
463 return hweight_long(w: *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits));
464 return __bitmap_weight_andnot(bitmap1: src1, bitmap2: src2, nbits);
465}
466
467static __always_inline
468void bitmap_set(unsigned long *map, unsigned int start, unsigned int nbits)
469{
470 if (__builtin_constant_p(nbits) && nbits == 1)
471 __set_bit(start, map);
472 else if (small_const_nbits(start + nbits))
473 *map |= GENMASK(start + nbits - 1, start);
474 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
475 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
476 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
477 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
478 memset((char *)map + start / 8, 0xff, nbits / 8);
479 else
480 __bitmap_set(map, start, len: nbits);
481}
482
483static __always_inline
484void bitmap_clear(unsigned long *map, unsigned int start, unsigned int nbits)
485{
486 if (__builtin_constant_p(nbits) && nbits == 1)
487 __clear_bit(start, map);
488 else if (small_const_nbits(start + nbits))
489 *map &= ~GENMASK(start + nbits - 1, start);
490 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
491 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
492 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
493 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
494 memset((char *)map + start / 8, 0, nbits / 8);
495 else
496 __bitmap_clear(map, start, len: nbits);
497}
498
499static __always_inline
500void bitmap_shift_right(unsigned long *dst, const unsigned long *src,
501 unsigned int shift, unsigned int nbits)
502{
503 if (small_const_nbits(nbits))
504 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;
505 else
506 __bitmap_shift_right(dst, src, shift, nbits);
507}
508
509static __always_inline
510void bitmap_shift_left(unsigned long *dst, const unsigned long *src,
511 unsigned int shift, unsigned int nbits)
512{
513 if (small_const_nbits(nbits))
514 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits);
515 else
516 __bitmap_shift_left(dst, src, shift, nbits);
517}
518
519static __always_inline
520void bitmap_replace(unsigned long *dst,
521 const unsigned long *old,
522 const unsigned long *new,
523 const unsigned long *mask,
524 unsigned int nbits)
525{
526 if (small_const_nbits(nbits))
527 *dst = (*old & ~(*mask)) | (*new & *mask);
528 else
529 __bitmap_replace(dst, old, new, mask, nbits);
530}
531
532/**
533 * bitmap_scatter - Scatter a bitmap according to the given mask
534 * @dst: scattered bitmap
535 * @src: gathered bitmap
536 * @mask: mask representing bits to assign to in the scattered bitmap
537 * @nbits: number of bits in each of these bitmaps
538 *
539 * Scatters bitmap with sequential bits according to the given @mask.
540 *
541 * Example:
542 * If @src bitmap = 0x005a, with @mask = 0x1313, @dst will be 0x0302.
543 *
544 * Or in binary form
545 * @src @mask @dst
546 * 0000000001011010 0001001100010011 0000001100000010
547 *
548 * (Bits 0, 1, 2, 3, 4, 5 are copied to the bits 0, 1, 4, 8, 9, 12)
549 *
550 * A more 'visual' description of the operation::
551 *
552 * src: 0000000001011010
553 * ||||||
554 * +------+|||||
555 * | +----+||||
556 * | |+----+|||
557 * | || +-+||
558 * | || | ||
559 * mask: ...v..vv...v..vv
560 * ...0..11...0..10
561 * dst: 0000001100000010
562 *
563 * A relationship exists between bitmap_scatter() and bitmap_gather(). See
564 * bitmap_gather() for the bitmap gather detailed operations. TL;DR:
565 * bitmap_gather() can be seen as the 'reverse' bitmap_scatter() operation.
566 */
567static __always_inline
568void bitmap_scatter(unsigned long *dst, const unsigned long *src,
569 const unsigned long *mask, unsigned int nbits)
570{
571 unsigned int n = 0;
572 unsigned int bit;
573
574 bitmap_zero(dst, nbits);
575
576 for_each_set_bit(bit, mask, nbits)
577 __assign_bit(bit, dst, test_bit(n++, src));
578}
579
580/**
581 * bitmap_gather - Gather a bitmap according to given mask
582 * @dst: gathered bitmap
583 * @src: scattered bitmap
584 * @mask: mask representing bits to extract from in the scattered bitmap
585 * @nbits: number of bits in each of these bitmaps
586 *
587 * Gathers bitmap with sparse bits according to the given @mask.
588 *
589 * Example:
590 * If @src bitmap = 0x0302, with @mask = 0x1313, @dst will be 0x001a.
591 *
592 * Or in binary form
593 * @src @mask @dst
594 * 0000001100000010 0001001100010011 0000000000011010
595 *
596 * (Bits 0, 1, 4, 8, 9, 12 are copied to the bits 0, 1, 2, 3, 4, 5)
597 *
598 * A more 'visual' description of the operation::
599 *
600 * mask: ...v..vv...v..vv
601 * src: 0000001100000010
602 * ^ ^^ ^ 0
603 * | || | 10
604 * | || > 010
605 * | |+--> 1010
606 * | +--> 11010
607 * +----> 011010
608 * dst: 0000000000011010
609 *
610 * A relationship exists between bitmap_gather() and bitmap_scatter(). See
611 * bitmap_scatter() for the bitmap scatter detailed operations. TL;DR:
612 * bitmap_scatter() can be seen as the 'reverse' bitmap_gather() operation.
613 *
614 * Suppose scattered computed using bitmap_scatter(scattered, src, mask, n).
615 * The operation bitmap_gather(result, scattered, mask, n) leads to a result
616 * equal or equivalent to src.
617 *
618 * The result can be 'equivalent' because bitmap_scatter() and bitmap_gather()
619 * are not bijective.
620 * The result and src values are equivalent in that sense that a call to
621 * bitmap_scatter(res, src, mask, n) and a call to
622 * bitmap_scatter(res, result, mask, n) will lead to the same res value.
623 */
624static __always_inline
625void bitmap_gather(unsigned long *dst, const unsigned long *src,
626 const unsigned long *mask, unsigned int nbits)
627{
628 unsigned int n = 0;
629 unsigned int bit;
630
631 bitmap_zero(dst, nbits);
632
633 for_each_set_bit(bit, mask, nbits)
634 __assign_bit(n++, dst, test_bit(bit, src));
635}
636
637static __always_inline
638void bitmap_next_set_region(unsigned long *bitmap, unsigned int *rs,
639 unsigned int *re, unsigned int end)
640{
641 *rs = find_next_bit(addr: bitmap, size: end, offset: *rs);
642 *re = find_next_zero_bit(addr: bitmap, size: end, offset: *rs + 1);
643}
644
645/**
646 * bitmap_release_region - release allocated bitmap region
647 * @bitmap: array of unsigned longs corresponding to the bitmap
648 * @pos: beginning of bit region to release
649 * @order: region size (log base 2 of number of bits) to release
650 *
651 * This is the complement to __bitmap_find_free_region() and releases
652 * the found region (by clearing it in the bitmap).
653 */
654static __always_inline
655void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
656{
657 bitmap_clear(map: bitmap, start: pos, BIT(order));
658}
659
660/**
661 * bitmap_allocate_region - allocate bitmap region
662 * @bitmap: array of unsigned longs corresponding to the bitmap
663 * @pos: beginning of bit region to allocate
664 * @order: region size (log base 2 of number of bits) to allocate
665 *
666 * Allocate (set bits in) a specified region of a bitmap.
667 *
668 * Returns: 0 on success, or %-EBUSY if specified region wasn't
669 * free (not all bits were zero).
670 */
671static __always_inline
672int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
673{
674 unsigned int len = BIT(order);
675
676 if (find_next_bit(addr: bitmap, size: pos + len, offset: pos) < pos + len)
677 return -EBUSY;
678 bitmap_set(map: bitmap, start: pos, nbits: len);
679 return 0;
680}
681
682/**
683 * bitmap_find_free_region - find a contiguous aligned mem region
684 * @bitmap: array of unsigned longs corresponding to the bitmap
685 * @bits: number of bits in the bitmap
686 * @order: region size (log base 2 of number of bits) to find
687 *
688 * Find a region of free (zero) bits in a @bitmap of @bits bits and
689 * allocate them (set them to one). Only consider regions of length
690 * a power (@order) of two, aligned to that power of two, which
691 * makes the search algorithm much faster.
692 *
693 * Returns: the bit offset in bitmap of the allocated region,
694 * or -errno on failure.
695 */
696static __always_inline
697int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
698{
699 unsigned int pos, end; /* scans bitmap by regions of size order */
700
701 for (pos = 0; (end = pos + BIT(order)) <= bits; pos = end) {
702 if (!bitmap_allocate_region(bitmap, pos, order))
703 return pos;
704 }
705 return -ENOMEM;
706}
707
708/**
709 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
710 * @n: u64 value
711 *
712 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit
713 * integers in 32-bit environment, and 64-bit integers in 64-bit one.
714 *
715 * There are four combinations of endianness and length of the word in linux
716 * ABIs: LE64, BE64, LE32 and BE32.
717 *
718 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in
719 * bitmaps and therefore don't require any special handling.
720 *
721 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory
722 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the
723 * other hand is represented as an array of 32-bit words and the position of
724 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that
725 * word. For example, bit #42 is located at 10th position of 2nd word.
726 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit
727 * values in memory as it usually does. But for BE we need to swap hi and lo
728 * words manually.
729 *
730 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and
731 * lo parts of u64. For LE32 it does nothing, and for BE environment it swaps
732 * hi and lo words, as is expected by bitmap.
733 */
734#if __BITS_PER_LONG == 64
735#define BITMAP_FROM_U64(n) (n)
736#else
737#define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \
738 ((unsigned long) ((u64)(n) >> 32))
739#endif
740
741/**
742 * bitmap_from_u64 - Check and swap words within u64.
743 * @mask: source bitmap
744 * @dst: destination bitmap
745 *
746 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``
747 * to read u64 mask, we will get the wrong word.
748 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,
749 * but we expect the lower 32-bits of u64.
750 */
751static __always_inline void bitmap_from_u64(unsigned long *dst, u64 mask)
752{
753 bitmap_from_arr64(dst, &mask, 64);
754}
755
756/**
757 * bitmap_read - read a value of n-bits from the memory region
758 * @map: address to the bitmap memory region
759 * @start: bit offset of the n-bit value
760 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG
761 *
762 * Returns: value of @nbits bits located at the @start bit offset within the
763 * @map memory region. For @nbits = 0 and @nbits > BITS_PER_LONG the return
764 * value is undefined.
765 */
766static __always_inline
767unsigned long bitmap_read(const unsigned long *map, unsigned long start, unsigned long nbits)
768{
769 size_t index = BIT_WORD(start);
770 unsigned long offset = start % BITS_PER_LONG;
771 unsigned long space = BITS_PER_LONG - offset;
772 unsigned long value_low, value_high;
773
774 if (unlikely(!nbits || nbits > BITS_PER_LONG))
775 return 0;
776
777 if (space >= nbits)
778 return (map[index] >> offset) & BITMAP_LAST_WORD_MASK(nbits);
779
780 value_low = map[index] & BITMAP_FIRST_WORD_MASK(start);
781 value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits);
782 return (value_low >> offset) | (value_high << space);
783}
784
785/**
786 * bitmap_write - write n-bit value within a memory region
787 * @map: address to the bitmap memory region
788 * @value: value to write, clamped to nbits
789 * @start: bit offset of the n-bit value
790 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG.
791 *
792 * bitmap_write() behaves as-if implemented as @nbits calls of __assign_bit(),
793 * i.e. bits beyond @nbits are ignored:
794 *
795 * for (bit = 0; bit < nbits; bit++)
796 * __assign_bit(start + bit, bitmap, val & BIT(bit));
797 *
798 * For @nbits == 0 and @nbits > BITS_PER_LONG no writes are performed.
799 */
800static __always_inline
801void bitmap_write(unsigned long *map, unsigned long value,
802 unsigned long start, unsigned long nbits)
803{
804 size_t index;
805 unsigned long offset;
806 unsigned long space;
807 unsigned long mask;
808 bool fit;
809
810 if (unlikely(!nbits || nbits > BITS_PER_LONG))
811 return;
812
813 mask = BITMAP_LAST_WORD_MASK(nbits);
814 value &= mask;
815 offset = start % BITS_PER_LONG;
816 space = BITS_PER_LONG - offset;
817 fit = space >= nbits;
818 index = BIT_WORD(start);
819
820 map[index] &= (fit ? (~(mask << offset)) : ~BITMAP_FIRST_WORD_MASK(start));
821 map[index] |= value << offset;
822 if (fit)
823 return;
824
825 map[index + 1] &= BITMAP_FIRST_WORD_MASK(start + nbits);
826 map[index + 1] |= (value >> space);
827}
828
829#define bitmap_get_value8(map, start) \
830 bitmap_read(map, start, BITS_PER_BYTE)
831#define bitmap_set_value8(map, value, start) \
832 bitmap_write(map, value, start, BITS_PER_BYTE)
833
834#endif /* __ASSEMBLY__ */
835
836#endif /* __LINUX_BITMAP_H */
837

source code of linux/include/linux/bitmap.h

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