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 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 */ 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 __always_inline 207 unsigned 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, 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 __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 } 240 241 static __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 } 250 251 static __always_inline 252 void 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 */ 265 static __always_inline 266 void 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 } 272 273 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 __always_inline 322 bool 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, src1, src2, nbits); 328 } 329 330 static __always_inline 331 void 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, src1, src2, nbits); 338 } 339 340 static __always_inline 341 void 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, src1, src2, nbits); 348 } 349 350 static __always_inline 351 bool 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, src1, src2, nbits); 357 } 358 359 static __always_inline 360 void 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) 374 375 static __always_inline 376 bool 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(src1, src2, nbits / 8); 383 return __bitmap_equal(src1, 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 */ 395 static __always_inline 396 bool 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 } 404 405 static __always_inline 406 bool 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(src1, src2, nbits); 412 } 413 414 static __always_inline 415 bool 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(src1, src2, nbits); 421 } 422 423 static __always_inline 424 bool 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(src, nbits) == nbits; 430 } 431 432 static __always_inline 433 bool 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(src, nbits) == nbits; 439 } 440 441 static __always_inline 442 unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits) 443 { 444 if (small_const_nbits(nbits)) 445 return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)); 446 return __bitmap_weight(src, nbits); 447 } 448 449 static __always_inline 450 unsigned 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(*src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)); 455 return __bitmap_weight_and(src1, src2, nbits); 456 } 457 458 static __always_inline 459 unsigned 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(*src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)); 464 return __bitmap_weight_andnot(src1, src2, nbits); 465 } 466 467 static __always_inline 468 void 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, nbits); 481 } 482 483 static __always_inline 484 void 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, nbits); 497 } 498 499 static __always_inline 500 void 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 } 508 509 static __always_inline 510 void 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 } 518 519 static __always_inline 520 void 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(). 564 * bitmap_gather() can be seen as the 'reverse' bitmap_scatter() operation. 565 * See bitmap_scatter() for details related to this relationship. 566 */ 567 static __always_inline 568 void 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. 612 * Suppose scattered computed using bitmap_scatter(scattered, src, mask, n). 613 * The operation bitmap_gather(result, scattered, mask, n) leads to a result 614 * equal or equivalent to src. 615 * 616 * The result can be 'equivalent' because bitmap_scatter() and bitmap_gather() 617 * are not bijective. 618 * The result and src values are equivalent in that sense that a call to 619 * bitmap_scatter(res, src, mask, n) and a call to 620 * bitmap_scatter(res, result, mask, n) will lead to the same res value. 621 */ 622 static __always_inline 623 void bitmap_gather(unsigned long *dst, const unsigned long *src, 624 const unsigned long *mask, unsigned int nbits) 625 { 626 unsigned int n = 0; 627 unsigned int bit; 628 629 bitmap_zero(dst, nbits); 630 631 for_each_set_bit(bit, mask, nbits) 632 __assign_bit(n++, dst, test_bit(bit, src)); 633 } 634 635 static __always_inline 636 void bitmap_next_set_region(unsigned long *bitmap, unsigned int *rs, 637 unsigned int *re, unsigned int end) 638 { 639 *rs = find_next_bit(bitmap, end, *rs); 640 *re = find_next_zero_bit(bitmap, end, *rs + 1); 641 } 642 643 /** 644 * bitmap_release_region - release allocated bitmap region 645 * @bitmap: array of unsigned longs corresponding to the bitmap 646 * @pos: beginning of bit region to release 647 * @order: region size (log base 2 of number of bits) to release 648 * 649 * This is the complement to __bitmap_find_free_region() and releases 650 * the found region (by clearing it in the bitmap). 651 */ 652 static __always_inline 653 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) 654 { 655 bitmap_clear(bitmap, pos, BIT(order)); 656 } 657 658 /** 659 * bitmap_allocate_region - allocate bitmap region 660 * @bitmap: array of unsigned longs corresponding to the bitmap 661 * @pos: beginning of bit region to allocate 662 * @order: region size (log base 2 of number of bits) to allocate 663 * 664 * Allocate (set bits in) a specified region of a bitmap. 665 * 666 * Returns: 0 on success, or %-EBUSY if specified region wasn't 667 * free (not all bits were zero). 668 */ 669 static __always_inline 670 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) 671 { 672 unsigned int len = BIT(order); 673 674 if (find_next_bit(bitmap, pos + len, pos) < pos + len) 675 return -EBUSY; 676 bitmap_set(bitmap, pos, len); 677 return 0; 678 } 679 680 /** 681 * bitmap_find_free_region - find a contiguous aligned mem region 682 * @bitmap: array of unsigned longs corresponding to the bitmap 683 * @bits: number of bits in the bitmap 684 * @order: region size (log base 2 of number of bits) to find 685 * 686 * Find a region of free (zero) bits in a @bitmap of @bits bits and 687 * allocate them (set them to one). Only consider regions of length 688 * a power (@order) of two, aligned to that power of two, which 689 * makes the search algorithm much faster. 690 * 691 * Returns: the bit offset in bitmap of the allocated region, 692 * or -errno on failure. 693 */ 694 static __always_inline 695 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order) 696 { 697 unsigned int pos, end; /* scans bitmap by regions of size order */ 698 699 for (pos = 0; (end = pos + BIT(order)) <= bits; pos = end) { 700 if (!bitmap_allocate_region(bitmap, pos, order)) 701 return pos; 702 } 703 return -ENOMEM; 704 } 705 706 /** 707 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap. 708 * @n: u64 value 709 * 710 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit 711 * integers in 32-bit environment, and 64-bit integers in 64-bit one. 712 * 713 * There are four combinations of endianness and length of the word in linux 714 * ABIs: LE64, BE64, LE32 and BE32. 715 * 716 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in 717 * bitmaps and therefore don't require any special handling. 718 * 719 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory 720 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the 721 * other hand is represented as an array of 32-bit words and the position of 722 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that 723 * word. For example, bit #42 is located at 10th position of 2nd word. 724 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit 725 * values in memory as it usually does. But for BE we need to swap hi and lo 726 * words manually. 727 * 728 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and 729 * lo parts of u64. For LE32 it does nothing, and for BE environment it swaps 730 * hi and lo words, as is expected by bitmap. 731 */ 732 #if __BITS_PER_LONG == 64 733 #define BITMAP_FROM_U64(n) (n) 734 #else 735 #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \ 736 ((unsigned long) ((u64)(n) >> 32)) 737 #endif 738 739 /** 740 * bitmap_from_u64 - Check and swap words within u64. 741 * @mask: source bitmap 742 * @dst: destination bitmap 743 * 744 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]`` 745 * to read u64 mask, we will get the wrong word. 746 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits, 747 * but we expect the lower 32-bits of u64. 748 */ 749 static __always_inline void bitmap_from_u64(unsigned long *dst, u64 mask) 750 { 751 bitmap_from_arr64(dst, &mask, 64); 752 } 753 754 /** 755 * bitmap_read - read a value of n-bits from the memory region 756 * @map: address to the bitmap memory region 757 * @start: bit offset of the n-bit value 758 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG 759 * 760 * Returns: value of @nbits bits located at the @start bit offset within the 761 * @map memory region. For @nbits = 0 and @nbits > BITS_PER_LONG the return 762 * value is undefined. 763 */ 764 static __always_inline 765 unsigned long bitmap_read(const unsigned long *map, unsigned long start, unsigned long nbits) 766 { 767 size_t index = BIT_WORD(start); 768 unsigned long offset = start % BITS_PER_LONG; 769 unsigned long space = BITS_PER_LONG - offset; 770 unsigned long value_low, value_high; 771 772 if (unlikely(!nbits || nbits > BITS_PER_LONG)) 773 return 0; 774 775 if (space >= nbits) 776 return (map[index] >> offset) & BITMAP_LAST_WORD_MASK(nbits); 777 778 value_low = map[index] & BITMAP_FIRST_WORD_MASK(start); 779 value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits); 780 return (value_low >> offset) | (value_high << space); 781 } 782 783 /** 784 * bitmap_write - write n-bit value within a memory region 785 * @map: address to the bitmap memory region 786 * @value: value to write, clamped to nbits 787 * @start: bit offset of the n-bit value 788 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG. 789 * 790 * bitmap_write() behaves as-if implemented as @nbits calls of __assign_bit(), 791 * i.e. bits beyond @nbits are ignored: 792 * 793 * for (bit = 0; bit < nbits; bit++) 794 * __assign_bit(start + bit, bitmap, val & BIT(bit)); 795 * 796 * For @nbits == 0 and @nbits > BITS_PER_LONG no writes are performed. 797 */ 798 static __always_inline 799 void bitmap_write(unsigned long *map, unsigned long value, 800 unsigned long start, unsigned long nbits) 801 { 802 size_t index; 803 unsigned long offset; 804 unsigned long space; 805 unsigned long mask; 806 bool fit; 807 808 if (unlikely(!nbits || nbits > BITS_PER_LONG)) 809 return; 810 811 mask = BITMAP_LAST_WORD_MASK(nbits); 812 value &= mask; 813 offset = start % BITS_PER_LONG; 814 space = BITS_PER_LONG - offset; 815 fit = space >= nbits; 816 index = BIT_WORD(start); 817 818 map[index] &= (fit ? (~(mask << offset)) : ~BITMAP_FIRST_WORD_MASK(start)); 819 map[index] |= value << offset; 820 if (fit) 821 return; 822 823 map[index + 1] &= BITMAP_FIRST_WORD_MASK(start + nbits); 824 map[index + 1] |= (value >> space); 825 } 826 827 #define bitmap_get_value8(map, start) \ 828 bitmap_read(map, start, BITS_PER_BYTE) 829 #define bitmap_set_value8(map, value, start) \ 830 bitmap_write(map, value, start, BITS_PER_BYTE) 831 832 #endif /* __ASSEMBLY__ */ 833 834 #endif /* __LINUX_BITMAP_H */ 835