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 __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 /* 274 * On 32-bit systems bitmaps are represented as u32 arrays internally. On LE64 275 * machines the order of hi and lo parts of numbers match the bitmap structure. 276 * In both cases conversion is not needed when copying data from/to arrays of 277 * u32. But in LE64 case, typecast in bitmap_copy_clear_tail() may lead 278 * to out-of-bound access. To avoid that, both LE and BE variants of 64-bit 279 * architectures are not using bitmap_copy_clear_tail(). 280 */ 281 #if BITS_PER_LONG == 64 282 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, 283 unsigned int nbits); 284 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, 285 unsigned int nbits); 286 #else 287 #define bitmap_from_arr32(bitmap, buf, nbits) \ 288 bitmap_copy_clear_tail((unsigned long *) (bitmap), \ 289 (const unsigned long *) (buf), (nbits)) 290 #define bitmap_to_arr32(buf, bitmap, nbits) \ 291 bitmap_copy_clear_tail((unsigned long *) (buf), \ 292 (const unsigned long *) (bitmap), (nbits)) 293 #endif 294 295 /* 296 * On 64-bit systems bitmaps are represented as u64 arrays internally. So, 297 * the conversion is not needed when copying data from/to arrays of u64. 298 */ 299 #if BITS_PER_LONG == 32 300 void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits); 301 void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits); 302 #else 303 #define bitmap_from_arr64(bitmap, buf, nbits) \ 304 bitmap_copy_clear_tail((unsigned long *)(bitmap), (const unsigned long *)(buf), (nbits)) 305 #define bitmap_to_arr64(buf, bitmap, nbits) \ 306 bitmap_copy_clear_tail((unsigned long *)(buf), (const unsigned long *)(bitmap), (nbits)) 307 #endif 308 309 static __always_inline 310 bool bitmap_and(unsigned long *dst, const unsigned long *src1, 311 const unsigned long *src2, unsigned int nbits) 312 { 313 if (small_const_nbits(nbits)) 314 return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0; 315 return __bitmap_and(dst, src1, src2, nbits); 316 } 317 318 static __always_inline 319 void bitmap_or(unsigned long *dst, const unsigned long *src1, 320 const unsigned long *src2, unsigned int nbits) 321 { 322 if (small_const_nbits(nbits)) 323 *dst = *src1 | *src2; 324 else 325 __bitmap_or(dst, src1, src2, nbits); 326 } 327 328 static __always_inline 329 void bitmap_xor(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_xor(dst, src1, src2, nbits); 336 } 337 338 static __always_inline 339 bool bitmap_andnot(unsigned long *dst, const unsigned long *src1, 340 const unsigned long *src2, unsigned int nbits) 341 { 342 if (small_const_nbits(nbits)) 343 return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0; 344 return __bitmap_andnot(dst, src1, src2, nbits); 345 } 346 347 static __always_inline 348 void bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int nbits) 349 { 350 if (small_const_nbits(nbits)) 351 *dst = ~(*src); 352 else 353 __bitmap_complement(dst, src, nbits); 354 } 355 356 #ifdef __LITTLE_ENDIAN 357 #define BITMAP_MEM_ALIGNMENT 8 358 #else 359 #define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long)) 360 #endif 361 #define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1) 362 363 static __always_inline 364 bool bitmap_equal(const unsigned long *src1, const unsigned long *src2, unsigned int nbits) 365 { 366 if (small_const_nbits(nbits)) 367 return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits)); 368 if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) && 369 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 370 return !memcmp(src1, src2, nbits / 8); 371 return __bitmap_equal(src1, src2, nbits); 372 } 373 374 /** 375 * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third 376 * @src1: Pointer to bitmap 1 377 * @src2: Pointer to bitmap 2 will be or'ed with bitmap 1 378 * @src3: Pointer to bitmap 3. Compare to the result of *@src1 | *@src2 379 * @nbits: number of bits in each of these bitmaps 380 * 381 * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise 382 */ 383 static __always_inline 384 bool bitmap_or_equal(const unsigned long *src1, const unsigned long *src2, 385 const unsigned long *src3, unsigned int nbits) 386 { 387 if (!small_const_nbits(nbits)) 388 return __bitmap_or_equal(src1, src2, src3, nbits); 389 390 return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits)); 391 } 392 393 static __always_inline 394 bool bitmap_intersects(const unsigned long *src1, const unsigned long *src2, unsigned int nbits) 395 { 396 if (small_const_nbits(nbits)) 397 return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0; 398 else 399 return __bitmap_intersects(src1, src2, nbits); 400 } 401 402 static __always_inline 403 bool bitmap_subset(const unsigned long *src1, const unsigned long *src2, unsigned int nbits) 404 { 405 if (small_const_nbits(nbits)) 406 return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits)); 407 else 408 return __bitmap_subset(src1, src2, nbits); 409 } 410 411 static __always_inline 412 bool bitmap_empty(const unsigned long *src, unsigned nbits) 413 { 414 if (small_const_nbits(nbits)) 415 return ! (*src & BITMAP_LAST_WORD_MASK(nbits)); 416 417 return find_first_bit(src, nbits) == nbits; 418 } 419 420 static __always_inline 421 bool bitmap_full(const unsigned long *src, unsigned int nbits) 422 { 423 if (small_const_nbits(nbits)) 424 return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits)); 425 426 return find_first_zero_bit(src, nbits) == nbits; 427 } 428 429 static __always_inline 430 unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits) 431 { 432 if (small_const_nbits(nbits)) 433 return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)); 434 return __bitmap_weight(src, nbits); 435 } 436 437 static __always_inline 438 unsigned long bitmap_weight_and(const unsigned long *src1, 439 const unsigned long *src2, unsigned int nbits) 440 { 441 if (small_const_nbits(nbits)) 442 return hweight_long(*src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)); 443 return __bitmap_weight_and(src1, src2, nbits); 444 } 445 446 static __always_inline 447 unsigned long bitmap_weight_andnot(const unsigned long *src1, 448 const unsigned long *src2, unsigned int nbits) 449 { 450 if (small_const_nbits(nbits)) 451 return hweight_long(*src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)); 452 return __bitmap_weight_andnot(src1, src2, nbits); 453 } 454 455 static __always_inline 456 void bitmap_set(unsigned long *map, unsigned int start, unsigned int nbits) 457 { 458 if (__builtin_constant_p(nbits) && nbits == 1) 459 __set_bit(start, map); 460 else if (small_const_nbits(start + nbits)) 461 *map |= GENMASK(start + nbits - 1, start); 462 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 463 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 464 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 465 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 466 memset((char *)map + start / 8, 0xff, nbits / 8); 467 else 468 __bitmap_set(map, start, nbits); 469 } 470 471 static __always_inline 472 void bitmap_clear(unsigned long *map, unsigned int start, unsigned int nbits) 473 { 474 if (__builtin_constant_p(nbits) && nbits == 1) 475 __clear_bit(start, map); 476 else if (small_const_nbits(start + nbits)) 477 *map &= ~GENMASK(start + nbits - 1, start); 478 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 479 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 480 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 481 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 482 memset((char *)map + start / 8, 0, nbits / 8); 483 else 484 __bitmap_clear(map, start, nbits); 485 } 486 487 static __always_inline 488 void bitmap_shift_right(unsigned long *dst, const unsigned long *src, 489 unsigned int shift, unsigned int nbits) 490 { 491 if (small_const_nbits(nbits)) 492 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift; 493 else 494 __bitmap_shift_right(dst, src, shift, nbits); 495 } 496 497 static __always_inline 498 void bitmap_shift_left(unsigned long *dst, const unsigned long *src, 499 unsigned int shift, unsigned int nbits) 500 { 501 if (small_const_nbits(nbits)) 502 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits); 503 else 504 __bitmap_shift_left(dst, src, shift, nbits); 505 } 506 507 static __always_inline 508 void bitmap_replace(unsigned long *dst, 509 const unsigned long *old, 510 const unsigned long *new, 511 const unsigned long *mask, 512 unsigned int nbits) 513 { 514 if (small_const_nbits(nbits)) 515 *dst = (*old & ~(*mask)) | (*new & *mask); 516 else 517 __bitmap_replace(dst, old, new, mask, nbits); 518 } 519 520 /** 521 * bitmap_scatter - Scatter a bitmap according to the given mask 522 * @dst: scattered bitmap 523 * @src: gathered bitmap 524 * @mask: mask representing bits to assign to in the scattered bitmap 525 * @nbits: number of bits in each of these bitmaps 526 * 527 * Scatters bitmap with sequential bits according to the given @mask. 528 * 529 * Example: 530 * If @src bitmap = 0x005a, with @mask = 0x1313, @dst will be 0x0302. 531 * 532 * Or in binary form 533 * @src @mask @dst 534 * 0000000001011010 0001001100010011 0000001100000010 535 * 536 * (Bits 0, 1, 2, 3, 4, 5 are copied to the bits 0, 1, 4, 8, 9, 12) 537 * 538 * A more 'visual' description of the operation:: 539 * 540 * src: 0000000001011010 541 * |||||| 542 * +------+||||| 543 * | +----+|||| 544 * | |+----+||| 545 * | || +-+|| 546 * | || | || 547 * mask: ...v..vv...v..vv 548 * ...0..11...0..10 549 * dst: 0000001100000010 550 * 551 * A relationship exists between bitmap_scatter() and bitmap_gather(). 552 * bitmap_gather() can be seen as the 'reverse' bitmap_scatter() operation. 553 * See bitmap_scatter() for details related to this relationship. 554 */ 555 static __always_inline 556 void bitmap_scatter(unsigned long *dst, const unsigned long *src, 557 const unsigned long *mask, unsigned int nbits) 558 { 559 unsigned int n = 0; 560 unsigned int bit; 561 562 bitmap_zero(dst, nbits); 563 564 for_each_set_bit(bit, mask, nbits) 565 __assign_bit(bit, dst, test_bit(n++, src)); 566 } 567 568 /** 569 * bitmap_gather - Gather a bitmap according to given mask 570 * @dst: gathered bitmap 571 * @src: scattered bitmap 572 * @mask: mask representing bits to extract from in the scattered bitmap 573 * @nbits: number of bits in each of these bitmaps 574 * 575 * Gathers bitmap with sparse bits according to the given @mask. 576 * 577 * Example: 578 * If @src bitmap = 0x0302, with @mask = 0x1313, @dst will be 0x001a. 579 * 580 * Or in binary form 581 * @src @mask @dst 582 * 0000001100000010 0001001100010011 0000000000011010 583 * 584 * (Bits 0, 1, 4, 8, 9, 12 are copied to the bits 0, 1, 2, 3, 4, 5) 585 * 586 * A more 'visual' description of the operation:: 587 * 588 * mask: ...v..vv...v..vv 589 * src: 0000001100000010 590 * ^ ^^ ^ 0 591 * | || | 10 592 * | || > 010 593 * | |+--> 1010 594 * | +--> 11010 595 * +----> 011010 596 * dst: 0000000000011010 597 * 598 * A relationship exists between bitmap_gather() and bitmap_scatter(). See 599 * bitmap_scatter() for the bitmap scatter detailed operations. 600 * Suppose scattered computed using bitmap_scatter(scattered, src, mask, n). 601 * The operation bitmap_gather(result, scattered, mask, n) leads to a result 602 * equal or equivalent to src. 603 * 604 * The result can be 'equivalent' because bitmap_scatter() and bitmap_gather() 605 * are not bijective. 606 * The result and src values are equivalent in that sense that a call to 607 * bitmap_scatter(res, src, mask, n) and a call to 608 * bitmap_scatter(res, result, mask, n) will lead to the same res value. 609 */ 610 static __always_inline 611 void bitmap_gather(unsigned long *dst, const unsigned long *src, 612 const unsigned long *mask, unsigned int nbits) 613 { 614 unsigned int n = 0; 615 unsigned int bit; 616 617 bitmap_zero(dst, nbits); 618 619 for_each_set_bit(bit, mask, nbits) 620 __assign_bit(n++, dst, test_bit(bit, src)); 621 } 622 623 static __always_inline 624 void bitmap_next_set_region(unsigned long *bitmap, unsigned int *rs, 625 unsigned int *re, unsigned int end) 626 { 627 *rs = find_next_bit(bitmap, end, *rs); 628 *re = find_next_zero_bit(bitmap, end, *rs + 1); 629 } 630 631 /** 632 * bitmap_release_region - release allocated bitmap region 633 * @bitmap: array of unsigned longs corresponding to the bitmap 634 * @pos: beginning of bit region to release 635 * @order: region size (log base 2 of number of bits) to release 636 * 637 * This is the complement to __bitmap_find_free_region() and releases 638 * the found region (by clearing it in the bitmap). 639 */ 640 static __always_inline 641 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) 642 { 643 bitmap_clear(bitmap, pos, BIT(order)); 644 } 645 646 /** 647 * bitmap_allocate_region - allocate bitmap region 648 * @bitmap: array of unsigned longs corresponding to the bitmap 649 * @pos: beginning of bit region to allocate 650 * @order: region size (log base 2 of number of bits) to allocate 651 * 652 * Allocate (set bits in) a specified region of a bitmap. 653 * 654 * Returns: 0 on success, or %-EBUSY if specified region wasn't 655 * free (not all bits were zero). 656 */ 657 static __always_inline 658 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) 659 { 660 unsigned int len = BIT(order); 661 662 if (find_next_bit(bitmap, pos + len, pos) < pos + len) 663 return -EBUSY; 664 bitmap_set(bitmap, pos, len); 665 return 0; 666 } 667 668 /** 669 * bitmap_find_free_region - find a contiguous aligned mem region 670 * @bitmap: array of unsigned longs corresponding to the bitmap 671 * @bits: number of bits in the bitmap 672 * @order: region size (log base 2 of number of bits) to find 673 * 674 * Find a region of free (zero) bits in a @bitmap of @bits bits and 675 * allocate them (set them to one). Only consider regions of length 676 * a power (@order) of two, aligned to that power of two, which 677 * makes the search algorithm much faster. 678 * 679 * Returns: the bit offset in bitmap of the allocated region, 680 * or -errno on failure. 681 */ 682 static __always_inline 683 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 __always_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 __always_inline 753 unsigned long bitmap_read(const unsigned long *map, unsigned long start, unsigned long nbits) 754 { 755 size_t index = BIT_WORD(start); 756 unsigned long offset = start % BITS_PER_LONG; 757 unsigned long space = BITS_PER_LONG - offset; 758 unsigned long value_low, value_high; 759 760 if (unlikely(!nbits || nbits > BITS_PER_LONG)) 761 return 0; 762 763 if (space >= nbits) 764 return (map[index] >> offset) & BITMAP_LAST_WORD_MASK(nbits); 765 766 value_low = map[index] & BITMAP_FIRST_WORD_MASK(start); 767 value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits); 768 return (value_low >> offset) | (value_high << space); 769 } 770 771 /** 772 * bitmap_write - write n-bit value within a memory region 773 * @map: address to the bitmap memory region 774 * @value: value to write, clamped to nbits 775 * @start: bit offset of the n-bit value 776 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG. 777 * 778 * bitmap_write() behaves as-if implemented as @nbits calls of __assign_bit(), 779 * i.e. bits beyond @nbits are ignored: 780 * 781 * for (bit = 0; bit < nbits; bit++) 782 * __assign_bit(start + bit, bitmap, val & BIT(bit)); 783 * 784 * For @nbits == 0 and @nbits > BITS_PER_LONG no writes are performed. 785 */ 786 static __always_inline 787 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