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
17 struct 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 include/asm-<arch>/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 */
132 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
133 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
134 unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node);
135 unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node);
136 void bitmap_free(const unsigned long *bitmap);
137
138 DEFINE_FREE(bitmap, unsigned long *, if (_T) bitmap_free(_T))
139
140 /* Managed variants of the above. */
141 unsigned long *devm_bitmap_alloc(struct device *dev,
142 unsigned int nbits, gfp_t flags);
143 unsigned 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
150 bool __bitmap_equal(const unsigned long *bitmap1,
151 const unsigned long *bitmap2, unsigned int nbits);
152 bool __pure __bitmap_or_equal(const unsigned long *src1,
153 const unsigned long *src2,
154 const unsigned long *src3,
155 unsigned int nbits);
156 void __bitmap_complement(unsigned long *dst, const unsigned long *src,
157 unsigned int nbits);
158 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
159 unsigned int shift, unsigned int nbits);
160 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
161 unsigned int shift, unsigned int nbits);
162 void bitmap_cut(unsigned long *dst, const unsigned long *src,
163 unsigned int first, unsigned int cut, unsigned int nbits);
164 bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
165 const unsigned long *bitmap2, unsigned int nbits);
166 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
167 const unsigned long *bitmap2, unsigned int nbits);
168 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
169 const unsigned long *bitmap2, unsigned int nbits);
170 bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
171 const unsigned long *bitmap2, unsigned int nbits);
172 void __bitmap_replace(unsigned long *dst,
173 const unsigned long *old, const unsigned long *new,
174 const unsigned long *mask, unsigned int nbits);
175 bool __bitmap_intersects(const unsigned long *bitmap1,
176 const unsigned long *bitmap2, unsigned int nbits);
177 bool __bitmap_subset(const unsigned long *bitmap1,
178 const unsigned long *bitmap2, unsigned int nbits);
179 unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
180 unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
181 const unsigned long *bitmap2, unsigned int nbits);
182 unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1,
183 const unsigned long *bitmap2, unsigned int nbits);
184 void __bitmap_set(unsigned long *map, unsigned int start, int len);
185 void __bitmap_clear(unsigned long *map, unsigned int start, int len);
186
187 unsigned 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 */
206 static inline unsigned long
207 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, 0);
215 }
216
217 void bitmap_remap(unsigned long *dst, const unsigned long *src,
218 const unsigned long *old, const unsigned long *new, unsigned int nbits);
219 int bitmap_bitremap(int oldbit,
220 const unsigned long *old, const unsigned long *new, int bits);
221 void bitmap_onto(unsigned long *dst, const unsigned long *orig,
222 const unsigned long *relmap, unsigned int bits);
223 void 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
231 static 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
241 static 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
251 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
252 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 */
265 static inline void bitmap_copy_clear_tail(unsigned long *dst,
266 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
273 static 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
294 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,
295 unsigned int nbits);
296 void 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
312 void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits);
313 void 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
321 static inline bool bitmap_and(unsigned long *dst, const unsigned long *src1,
322 const unsigned long *src2, unsigned int nbits)
323 {
324 if (small_const_nbits(nbits))
325 return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
326 return __bitmap_and(dst, src1, src2, nbits);
327 }
328
329 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
330 const unsigned long *src2, unsigned int nbits)
331 {
332 if (small_const_nbits(nbits))
333 *dst = *src1 | *src2;
334 else
335 __bitmap_or(dst, src1, src2, nbits);
336 }
337
338 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
339 const unsigned long *src2, unsigned int nbits)
340 {
341 if (small_const_nbits(nbits))
342 *dst = *src1 ^ *src2;
343 else
344 __bitmap_xor(dst, src1, src2, nbits);
345 }
346
347 static inline bool bitmap_andnot(unsigned long *dst, const unsigned long *src1,
348 const unsigned long *src2, unsigned int nbits)
349 {
350 if (small_const_nbits(nbits))
351 return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
352 return __bitmap_andnot(dst, src1, src2, nbits);
353 }
354
355 static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
356 unsigned int nbits)
357 {
358 if (small_const_nbits(nbits))
359 *dst = ~(*src);
360 else
361 __bitmap_complement(dst, src, nbits);
362 }
363
364 #ifdef __LITTLE_ENDIAN
365 #define BITMAP_MEM_ALIGNMENT 8
366 #else
367 #define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
368 #endif
369 #define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)
370
371 static inline bool bitmap_equal(const unsigned long *src1,
372 const unsigned long *src2, unsigned int nbits)
373 {
374 if (small_const_nbits(nbits))
375 return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
376 if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
377 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
378 return !memcmp(src1, src2, nbits / 8);
379 return __bitmap_equal(src1, src2, nbits);
380 }
381
382 /**
383 * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third
384 * @src1: Pointer to bitmap 1
385 * @src2: Pointer to bitmap 2 will be or'ed with bitmap 1
386 * @src3: Pointer to bitmap 3. Compare to the result of *@src1 | *@src2
387 * @nbits: number of bits in each of these bitmaps
388 *
389 * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
390 */
391 static inline bool bitmap_or_equal(const unsigned long *src1,
392 const unsigned long *src2,
393 const unsigned long *src3,
394 unsigned int nbits)
395 {
396 if (!small_const_nbits(nbits))
397 return __bitmap_or_equal(src1, src2, src3, nbits);
398
399 return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
400 }
401
402 static inline bool bitmap_intersects(const unsigned long *src1,
403 const unsigned long *src2,
404 unsigned int nbits)
405 {
406 if (small_const_nbits(nbits))
407 return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
408 else
409 return __bitmap_intersects(src1, src2, nbits);
410 }
411
412 static inline bool bitmap_subset(const unsigned long *src1,
413 const unsigned long *src2, unsigned int nbits)
414 {
415 if (small_const_nbits(nbits))
416 return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
417 else
418 return __bitmap_subset(src1, src2, nbits);
419 }
420
421 static inline bool bitmap_empty(const unsigned long *src, unsigned nbits)
422 {
423 if (small_const_nbits(nbits))
424 return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
425
426 return find_first_bit(src, nbits) == nbits;
427 }
428
429 static inline bool bitmap_full(const unsigned long *src, unsigned int nbits)
430 {
431 if (small_const_nbits(nbits))
432 return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
433
434 return find_first_zero_bit(src, nbits) == nbits;
435 }
436
437 static __always_inline
438 unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits)
439 {
440 if (small_const_nbits(nbits))
441 return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
442 return __bitmap_weight(src, nbits);
443 }
444
445 static __always_inline
446 unsigned long bitmap_weight_and(const unsigned long *src1,
447 const unsigned long *src2, unsigned int nbits)
448 {
449 if (small_const_nbits(nbits))
450 return hweight_long(*src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits));
451 return __bitmap_weight_and(src1, src2, nbits);
452 }
453
454 static __always_inline
455 unsigned long bitmap_weight_andnot(const unsigned long *src1,
456 const unsigned long *src2, unsigned int nbits)
457 {
458 if (small_const_nbits(nbits))
459 return hweight_long(*src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits));
460 return __bitmap_weight_andnot(src1, src2, nbits);
461 }
462
463 static __always_inline void bitmap_set(unsigned long *map, unsigned int start,
464 unsigned int nbits)
465 {
466 if (__builtin_constant_p(nbits) && nbits == 1)
467 __set_bit(start, map);
468 else if (small_const_nbits(start + nbits))
469 *map |= GENMASK(start + nbits - 1, start);
470 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
471 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
472 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
473 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
474 memset((char *)map + start / 8, 0xff, nbits / 8);
475 else
476 __bitmap_set(map, start, nbits);
477 }
478
479 static __always_inline void bitmap_clear(unsigned long *map, unsigned int start,
480 unsigned int nbits)
481 {
482 if (__builtin_constant_p(nbits) && nbits == 1)
483 __clear_bit(start, map);
484 else if (small_const_nbits(start + nbits))
485 *map &= ~GENMASK(start + nbits - 1, start);
486 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
487 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
488 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
489 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
490 memset((char *)map + start / 8, 0, nbits / 8);
491 else
492 __bitmap_clear(map, start, nbits);
493 }
494
495 static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src,
496 unsigned int shift, unsigned int nbits)
497 {
498 if (small_const_nbits(nbits))
499 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;
500 else
501 __bitmap_shift_right(dst, src, shift, nbits);
502 }
503
504 static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src,
505 unsigned int shift, unsigned int nbits)
506 {
507 if (small_const_nbits(nbits))
508 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits);
509 else
510 __bitmap_shift_left(dst, src, shift, nbits);
511 }
512
513 static inline void bitmap_replace(unsigned long *dst,
514 const unsigned long *old,
515 const unsigned long *new,
516 const unsigned long *mask,
517 unsigned int nbits)
518 {
519 if (small_const_nbits(nbits))
520 *dst = (*old & ~(*mask)) | (*new & *mask);
521 else
522 __bitmap_replace(dst, old, new, mask, nbits);
523 }
524
525 /**
526 * bitmap_scatter - Scatter a bitmap according to the given mask
527 * @dst: scattered bitmap
528 * @src: gathered bitmap
529 * @mask: mask representing bits to assign to in the scattered bitmap
530 * @nbits: number of bits in each of these bitmaps
531 *
532 * Scatters bitmap with sequential bits according to the given @mask.
533 *
534 * Example:
535 * If @src bitmap = 0x005a, with @mask = 0x1313, @dst will be 0x0302.
536 *
537 * Or in binary form
538 * @src @mask @dst
539 * 0000000001011010 0001001100010011 0000001100000010
540 *
541 * (Bits 0, 1, 2, 3, 4, 5 are copied to the bits 0, 1, 4, 8, 9, 12)
542 *
543 * A more 'visual' description of the operation::
544 *
545 * src: 0000000001011010
546 * ||||||
547 * +------+|||||
548 * | +----+||||
549 * | |+----+|||
550 * | || +-+||
551 * | || | ||
552 * mask: ...v..vv...v..vv
553 * ...0..11...0..10
554 * dst: 0000001100000010
555 *
556 * A relationship exists between bitmap_scatter() and bitmap_gather().
557 * bitmap_gather() can be seen as the 'reverse' bitmap_scatter() operation.
558 * See bitmap_scatter() for details related to this relationship.
559 */
560 static inline void bitmap_scatter(unsigned long *dst, const unsigned long *src,
561 const unsigned long *mask, unsigned int nbits)
562 {
563 unsigned int n = 0;
564 unsigned int bit;
565
566 bitmap_zero(dst, nbits);
567
568 for_each_set_bit(bit, mask, nbits)
569 __assign_bit(bit, dst, test_bit(n++, src));
570 }
571
572 /**
573 * bitmap_gather - Gather a bitmap according to given mask
574 * @dst: gathered bitmap
575 * @src: scattered bitmap
576 * @mask: mask representing bits to extract from in the scattered bitmap
577 * @nbits: number of bits in each of these bitmaps
578 *
579 * Gathers bitmap with sparse bits according to the given @mask.
580 *
581 * Example:
582 * If @src bitmap = 0x0302, with @mask = 0x1313, @dst will be 0x001a.
583 *
584 * Or in binary form
585 * @src @mask @dst
586 * 0000001100000010 0001001100010011 0000000000011010
587 *
588 * (Bits 0, 1, 4, 8, 9, 12 are copied to the bits 0, 1, 2, 3, 4, 5)
589 *
590 * A more 'visual' description of the operation::
591 *
592 * mask: ...v..vv...v..vv
593 * src: 0000001100000010
594 * ^ ^^ ^ 0
595 * | || | 10
596 * | || > 010
597 * | |+--> 1010
598 * | +--> 11010
599 * +----> 011010
600 * dst: 0000000000011010
601 *
602 * A relationship exists between bitmap_gather() and bitmap_scatter(). See
603 * bitmap_scatter() for the bitmap scatter detailed operations.
604 * Suppose scattered computed using bitmap_scatter(scattered, src, mask, n).
605 * The operation bitmap_gather(result, scattered, mask, n) leads to a result
606 * equal or equivalent to src.
607 *
608 * The result can be 'equivalent' because bitmap_scatter() and bitmap_gather()
609 * are not bijective.
610 * The result and src values are equivalent in that sense that a call to
611 * bitmap_scatter(res, src, mask, n) and a call to
612 * bitmap_scatter(res, result, mask, n) will lead to the same res value.
613 */
614 static inline void bitmap_gather(unsigned long *dst, const unsigned long *src,
615 const unsigned long *mask, unsigned int nbits)
616 {
617 unsigned int n = 0;
618 unsigned int bit;
619
620 bitmap_zero(dst, nbits);
621
622 for_each_set_bit(bit, mask, nbits)
623 __assign_bit(n++, dst, test_bit(bit, src));
624 }
625
626 static inline void bitmap_next_set_region(unsigned long *bitmap,
627 unsigned int *rs, unsigned int *re,
628 unsigned int end)
629 {
630 *rs = find_next_bit(bitmap, end, *rs);
631 *re = find_next_zero_bit(bitmap, end, *rs + 1);
632 }
633
634 /**
635 * bitmap_release_region - release allocated bitmap region
636 * @bitmap: array of unsigned longs corresponding to the bitmap
637 * @pos: beginning of bit region to release
638 * @order: region size (log base 2 of number of bits) to release
639 *
640 * This is the complement to __bitmap_find_free_region() and releases
641 * the found region (by clearing it in the bitmap).
642 */
643 static inline void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
644 {
645 bitmap_clear(bitmap, pos, BIT(order));
646 }
647
648 /**
649 * bitmap_allocate_region - allocate bitmap region
650 * @bitmap: array of unsigned longs corresponding to the bitmap
651 * @pos: beginning of bit region to allocate
652 * @order: region size (log base 2 of number of bits) to allocate
653 *
654 * Allocate (set bits in) a specified region of a bitmap.
655 *
656 * Returns: 0 on success, or %-EBUSY if specified region wasn't
657 * free (not all bits were zero).
658 */
659 static inline int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
660 {
661 unsigned int len = BIT(order);
662
663 if (find_next_bit(bitmap, pos + len, pos) < pos + len)
664 return -EBUSY;
665 bitmap_set(bitmap, pos, len);
666 return 0;
667 }
668
669 /**
670 * bitmap_find_free_region - find a contiguous aligned mem region
671 * @bitmap: array of unsigned longs corresponding to the bitmap
672 * @bits: number of bits in the bitmap
673 * @order: region size (log base 2 of number of bits) to find
674 *
675 * Find a region of free (zero) bits in a @bitmap of @bits bits and
676 * allocate them (set them to one). Only consider regions of length
677 * a power (@order) of two, aligned to that power of two, which
678 * makes the search algorithm much faster.
679 *
680 * Returns: the bit offset in bitmap of the allocated region,
681 * or -errno on failure.
682 */
683 static inline int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
684 {
685 unsigned int pos, end; /* scans bitmap by regions of size order */
686
687 for (pos = 0; (end = pos + BIT(order)) <= bits; pos = end) {
688 if (!bitmap_allocate_region(bitmap, pos, order))
689 return pos;
690 }
691 return -ENOMEM;
692 }
693
694 /**
695 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
696 * @n: u64 value
697 *
698 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit
699 * integers in 32-bit environment, and 64-bit integers in 64-bit one.
700 *
701 * There are four combinations of endianness and length of the word in linux
702 * ABIs: LE64, BE64, LE32 and BE32.
703 *
704 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in
705 * bitmaps and therefore don't require any special handling.
706 *
707 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory
708 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the
709 * other hand is represented as an array of 32-bit words and the position of
710 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that
711 * word. For example, bit #42 is located at 10th position of 2nd word.
712 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit
713 * values in memory as it usually does. But for BE we need to swap hi and lo
714 * words manually.
715 *
716 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and
717 * lo parts of u64. For LE32 it does nothing, and for BE environment it swaps
718 * hi and lo words, as is expected by bitmap.
719 */
720 #if __BITS_PER_LONG == 64
721 #define BITMAP_FROM_U64(n) (n)
722 #else
723 #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \
724 ((unsigned long) ((u64)(n) >> 32))
725 #endif
726
727 /**
728 * bitmap_from_u64 - Check and swap words within u64.
729 * @mask: source bitmap
730 * @dst: destination bitmap
731 *
732 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``
733 * to read u64 mask, we will get the wrong word.
734 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,
735 * but we expect the lower 32-bits of u64.
736 */
737 static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
738 {
739 bitmap_from_arr64(dst, &mask, 64);
740 }
741
742 /**
743 * bitmap_read - read a value of n-bits from the memory region
744 * @map: address to the bitmap memory region
745 * @start: bit offset of the n-bit value
746 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG
747 *
748 * Returns: value of @nbits bits located at the @start bit offset within the
749 * @map memory region. For @nbits = 0 and @nbits > BITS_PER_LONG the return
750 * value is undefined.
751 */
752 static inline unsigned long bitmap_read(const unsigned long *map,
753 unsigned long start,
754 unsigned long nbits)
755 {
756 size_t index = BIT_WORD(start);
757 unsigned long offset = start % BITS_PER_LONG;
758 unsigned long space = BITS_PER_LONG - offset;
759 unsigned long value_low, value_high;
760
761 if (unlikely(!nbits || nbits > BITS_PER_LONG))
762 return 0;
763
764 if (space >= nbits)
765 return (map[index] >> offset) & BITMAP_LAST_WORD_MASK(nbits);
766
767 value_low = map[index] & BITMAP_FIRST_WORD_MASK(start);
768 value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits);
769 return (value_low >> offset) | (value_high << space);
770 }
771
772 /**
773 * bitmap_write - write n-bit value within a memory region
774 * @map: address to the bitmap memory region
775 * @value: value to write, clamped to nbits
776 * @start: bit offset of the n-bit value
777 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG.
778 *
779 * bitmap_write() behaves as-if implemented as @nbits calls of __assign_bit(),
780 * i.e. bits beyond @nbits are ignored:
781 *
782 * for (bit = 0; bit < nbits; bit++)
783 * __assign_bit(start + bit, bitmap, val & BIT(bit));
784 *
785 * For @nbits == 0 and @nbits > BITS_PER_LONG no writes are performed.
786 */
787 static inline void bitmap_write(unsigned long *map, unsigned long value,
788 unsigned long start, unsigned long nbits)
789 {
790 size_t index;
791 unsigned long offset;
792 unsigned long space;
793 unsigned long mask;
794 bool fit;
795
796 if (unlikely(!nbits || nbits > BITS_PER_LONG))
797 return;
798
799 mask = BITMAP_LAST_WORD_MASK(nbits);
800 value &= mask;
801 offset = start % BITS_PER_LONG;
802 space = BITS_PER_LONG - offset;
803 fit = space >= nbits;
804 index = BIT_WORD(start);
805
806 map[index] &= (fit ? (~(mask << offset)) : ~BITMAP_FIRST_WORD_MASK(start));
807 map[index] |= value << offset;
808 if (fit)
809 return;
810
811 map[index + 1] &= BITMAP_FIRST_WORD_MASK(start + nbits);
812 map[index + 1] |= (value >> space);
813 }
814
815 #define bitmap_get_value8(map, start) \
816 bitmap_read(map, start, BITS_PER_BYTE)
817 #define bitmap_set_value8(map, value, start) \
818 bitmap_write(map, value, start, BITS_PER_BYTE)
819
820 #endif /* __ASSEMBLY__ */
821
822 #endif /* __LINUX_BITMAP_H */
823
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