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 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits) 230 { 231 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 232 233 if (small_const_nbits(nbits)) 234 *dst = 0; 235 else 236 memset(dst, 0, len); 237 } 238 239 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits) 240 { 241 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 242 243 if (small_const_nbits(nbits)) 244 *dst = ~0UL; 245 else 246 memset(dst, 0xff, len); 247 } 248 249 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src, 250 unsigned int nbits) 251 { 252 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 253 254 if (small_const_nbits(nbits)) 255 *dst = *src; 256 else 257 memcpy(dst, src, len); 258 } 259 260 /* 261 * Copy bitmap and clear tail bits in last word. 262 */ 263 static inline void bitmap_copy_clear_tail(unsigned long *dst, 264 const unsigned long *src, unsigned int nbits) 265 { 266 bitmap_copy(dst, src, nbits); 267 if (nbits % BITS_PER_LONG) 268 dst[nbits / BITS_PER_LONG] &= BITMAP_LAST_WORD_MASK(nbits); 269 } 270 271 /* 272 * On 32-bit systems bitmaps are represented as u32 arrays internally. On LE64 273 * machines the order of hi and lo parts of numbers match the bitmap structure. 274 * In both cases conversion is not needed when copying data from/to arrays of 275 * u32. But in LE64 case, typecast in bitmap_copy_clear_tail() may lead 276 * to out-of-bound access. To avoid that, both LE and BE variants of 64-bit 277 * architectures are not using bitmap_copy_clear_tail(). 278 */ 279 #if BITS_PER_LONG == 64 280 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, 281 unsigned int nbits); 282 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, 283 unsigned int nbits); 284 #else 285 #define bitmap_from_arr32(bitmap, buf, nbits) \ 286 bitmap_copy_clear_tail((unsigned long *) (bitmap), \ 287 (const unsigned long *) (buf), (nbits)) 288 #define bitmap_to_arr32(buf, bitmap, nbits) \ 289 bitmap_copy_clear_tail((unsigned long *) (buf), \ 290 (const unsigned long *) (bitmap), (nbits)) 291 #endif 292 293 /* 294 * On 64-bit systems bitmaps are represented as u64 arrays internally. So, 295 * the conversion is not needed when copying data from/to arrays of u64. 296 */ 297 #if BITS_PER_LONG == 32 298 void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits); 299 void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits); 300 #else 301 #define bitmap_from_arr64(bitmap, buf, nbits) \ 302 bitmap_copy_clear_tail((unsigned long *)(bitmap), (const unsigned long *)(buf), (nbits)) 303 #define bitmap_to_arr64(buf, bitmap, nbits) \ 304 bitmap_copy_clear_tail((unsigned long *)(buf), (const unsigned long *)(bitmap), (nbits)) 305 #endif 306 307 static inline bool bitmap_and(unsigned long *dst, const unsigned long *src1, 308 const unsigned long *src2, unsigned int nbits) 309 { 310 if (small_const_nbits(nbits)) 311 return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0; 312 return __bitmap_and(dst, src1, src2, nbits); 313 } 314 315 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1, 316 const unsigned long *src2, unsigned int nbits) 317 { 318 if (small_const_nbits(nbits)) 319 *dst = *src1 | *src2; 320 else 321 __bitmap_or(dst, src1, src2, nbits); 322 } 323 324 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1, 325 const unsigned long *src2, unsigned int nbits) 326 { 327 if (small_const_nbits(nbits)) 328 *dst = *src1 ^ *src2; 329 else 330 __bitmap_xor(dst, src1, src2, nbits); 331 } 332 333 static inline bool bitmap_andnot(unsigned long *dst, const unsigned long *src1, 334 const unsigned long *src2, unsigned int nbits) 335 { 336 if (small_const_nbits(nbits)) 337 return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0; 338 return __bitmap_andnot(dst, src1, src2, nbits); 339 } 340 341 static inline void bitmap_complement(unsigned long *dst, const unsigned long *src, 342 unsigned int nbits) 343 { 344 if (small_const_nbits(nbits)) 345 *dst = ~(*src); 346 else 347 __bitmap_complement(dst, src, nbits); 348 } 349 350 #ifdef __LITTLE_ENDIAN 351 #define BITMAP_MEM_ALIGNMENT 8 352 #else 353 #define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long)) 354 #endif 355 #define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1) 356 357 static inline bool bitmap_equal(const unsigned long *src1, 358 const unsigned long *src2, unsigned int nbits) 359 { 360 if (small_const_nbits(nbits)) 361 return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits)); 362 if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) && 363 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 364 return !memcmp(src1, src2, nbits / 8); 365 return __bitmap_equal(src1, src2, nbits); 366 } 367 368 /** 369 * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third 370 * @src1: Pointer to bitmap 1 371 * @src2: Pointer to bitmap 2 will be or'ed with bitmap 1 372 * @src3: Pointer to bitmap 3. Compare to the result of *@src1 | *@src2 373 * @nbits: number of bits in each of these bitmaps 374 * 375 * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise 376 */ 377 static inline bool bitmap_or_equal(const unsigned long *src1, 378 const unsigned long *src2, 379 const unsigned long *src3, 380 unsigned int nbits) 381 { 382 if (!small_const_nbits(nbits)) 383 return __bitmap_or_equal(src1, src2, src3, nbits); 384 385 return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits)); 386 } 387 388 static inline bool bitmap_intersects(const unsigned long *src1, 389 const unsigned long *src2, 390 unsigned int nbits) 391 { 392 if (small_const_nbits(nbits)) 393 return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0; 394 else 395 return __bitmap_intersects(src1, src2, nbits); 396 } 397 398 static inline bool bitmap_subset(const unsigned long *src1, 399 const unsigned long *src2, unsigned int nbits) 400 { 401 if (small_const_nbits(nbits)) 402 return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits)); 403 else 404 return __bitmap_subset(src1, src2, nbits); 405 } 406 407 static inline bool bitmap_empty(const unsigned long *src, unsigned nbits) 408 { 409 if (small_const_nbits(nbits)) 410 return ! (*src & BITMAP_LAST_WORD_MASK(nbits)); 411 412 return find_first_bit(src, nbits) == nbits; 413 } 414 415 static inline bool bitmap_full(const unsigned long *src, unsigned int nbits) 416 { 417 if (small_const_nbits(nbits)) 418 return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits)); 419 420 return find_first_zero_bit(src, nbits) == nbits; 421 } 422 423 static __always_inline 424 unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits) 425 { 426 if (small_const_nbits(nbits)) 427 return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)); 428 return __bitmap_weight(src, nbits); 429 } 430 431 static __always_inline 432 unsigned long bitmap_weight_and(const unsigned long *src1, 433 const unsigned long *src2, unsigned int nbits) 434 { 435 if (small_const_nbits(nbits)) 436 return hweight_long(*src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)); 437 return __bitmap_weight_and(src1, src2, nbits); 438 } 439 440 static __always_inline 441 unsigned long bitmap_weight_andnot(const unsigned long *src1, 442 const unsigned long *src2, unsigned int nbits) 443 { 444 if (small_const_nbits(nbits)) 445 return hweight_long(*src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)); 446 return __bitmap_weight_andnot(src1, src2, nbits); 447 } 448 449 static __always_inline void bitmap_set(unsigned long *map, unsigned int start, 450 unsigned int nbits) 451 { 452 if (__builtin_constant_p(nbits) && nbits == 1) 453 __set_bit(start, map); 454 else if (small_const_nbits(start + nbits)) 455 *map |= GENMASK(start + nbits - 1, start); 456 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 457 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 458 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 459 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 460 memset((char *)map + start / 8, 0xff, nbits / 8); 461 else 462 __bitmap_set(map, start, nbits); 463 } 464 465 static __always_inline void bitmap_clear(unsigned long *map, unsigned int start, 466 unsigned int nbits) 467 { 468 if (__builtin_constant_p(nbits) && nbits == 1) 469 __clear_bit(start, map); 470 else if (small_const_nbits(start + nbits)) 471 *map &= ~GENMASK(start + nbits - 1, start); 472 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 473 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 474 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 475 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 476 memset((char *)map + start / 8, 0, nbits / 8); 477 else 478 __bitmap_clear(map, start, nbits); 479 } 480 481 static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src, 482 unsigned int shift, unsigned int nbits) 483 { 484 if (small_const_nbits(nbits)) 485 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift; 486 else 487 __bitmap_shift_right(dst, src, shift, nbits); 488 } 489 490 static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src, 491 unsigned int shift, unsigned int nbits) 492 { 493 if (small_const_nbits(nbits)) 494 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits); 495 else 496 __bitmap_shift_left(dst, src, shift, nbits); 497 } 498 499 static inline void bitmap_replace(unsigned long *dst, 500 const unsigned long *old, 501 const unsigned long *new, 502 const unsigned long *mask, 503 unsigned int nbits) 504 { 505 if (small_const_nbits(nbits)) 506 *dst = (*old & ~(*mask)) | (*new & *mask); 507 else 508 __bitmap_replace(dst, old, new, mask, nbits); 509 } 510 511 /** 512 * bitmap_scatter - Scatter a bitmap according to the given mask 513 * @dst: scattered bitmap 514 * @src: gathered bitmap 515 * @mask: mask representing bits to assign to in the scattered bitmap 516 * @nbits: number of bits in each of these bitmaps 517 * 518 * Scatters bitmap with sequential bits according to the given @mask. 519 * 520 * Example: 521 * If @src bitmap = 0x005a, with @mask = 0x1313, @dst will be 0x0302. 522 * 523 * Or in binary form 524 * @src @mask @dst 525 * 0000000001011010 0001001100010011 0000001100000010 526 * 527 * (Bits 0, 1, 2, 3, 4, 5 are copied to the bits 0, 1, 4, 8, 9, 12) 528 * 529 * A more 'visual' description of the operation:: 530 * 531 * src: 0000000001011010 532 * |||||| 533 * +------+||||| 534 * | +----+|||| 535 * | |+----+||| 536 * | || +-+|| 537 * | || | || 538 * mask: ...v..vv...v..vv 539 * ...0..11...0..10 540 * dst: 0000001100000010 541 * 542 * A relationship exists between bitmap_scatter() and bitmap_gather(). 543 * bitmap_gather() can be seen as the 'reverse' bitmap_scatter() operation. 544 * See bitmap_scatter() for details related to this relationship. 545 */ 546 static inline void bitmap_scatter(unsigned long *dst, const unsigned long *src, 547 const unsigned long *mask, unsigned int nbits) 548 { 549 unsigned int n = 0; 550 unsigned int bit; 551 552 bitmap_zero(dst, nbits); 553 554 for_each_set_bit(bit, mask, nbits) 555 __assign_bit(bit, dst, test_bit(n++, src)); 556 } 557 558 /** 559 * bitmap_gather - Gather a bitmap according to given mask 560 * @dst: gathered bitmap 561 * @src: scattered bitmap 562 * @mask: mask representing bits to extract from in the scattered bitmap 563 * @nbits: number of bits in each of these bitmaps 564 * 565 * Gathers bitmap with sparse bits according to the given @mask. 566 * 567 * Example: 568 * If @src bitmap = 0x0302, with @mask = 0x1313, @dst will be 0x001a. 569 * 570 * Or in binary form 571 * @src @mask @dst 572 * 0000001100000010 0001001100010011 0000000000011010 573 * 574 * (Bits 0, 1, 4, 8, 9, 12 are copied to the bits 0, 1, 2, 3, 4, 5) 575 * 576 * A more 'visual' description of the operation:: 577 * 578 * mask: ...v..vv...v..vv 579 * src: 0000001100000010 580 * ^ ^^ ^ 0 581 * | || | 10 582 * | || > 010 583 * | |+--> 1010 584 * | +--> 11010 585 * +----> 011010 586 * dst: 0000000000011010 587 * 588 * A relationship exists between bitmap_gather() and bitmap_scatter(). See 589 * bitmap_scatter() for the bitmap scatter detailed operations. 590 * Suppose scattered computed using bitmap_scatter(scattered, src, mask, n). 591 * The operation bitmap_gather(result, scattered, mask, n) leads to a result 592 * equal or equivalent to src. 593 * 594 * The result can be 'equivalent' because bitmap_scatter() and bitmap_gather() 595 * are not bijective. 596 * The result and src values are equivalent in that sense that a call to 597 * bitmap_scatter(res, src, mask, n) and a call to 598 * bitmap_scatter(res, result, mask, n) will lead to the same res value. 599 */ 600 static inline void bitmap_gather(unsigned long *dst, const unsigned long *src, 601 const unsigned long *mask, unsigned int nbits) 602 { 603 unsigned int n = 0; 604 unsigned int bit; 605 606 bitmap_zero(dst, nbits); 607 608 for_each_set_bit(bit, mask, nbits) 609 __assign_bit(n++, dst, test_bit(bit, src)); 610 } 611 612 static inline void bitmap_next_set_region(unsigned long *bitmap, 613 unsigned int *rs, unsigned int *re, 614 unsigned int end) 615 { 616 *rs = find_next_bit(bitmap, end, *rs); 617 *re = find_next_zero_bit(bitmap, end, *rs + 1); 618 } 619 620 /** 621 * bitmap_release_region - release allocated bitmap region 622 * @bitmap: array of unsigned longs corresponding to the bitmap 623 * @pos: beginning of bit region to release 624 * @order: region size (log base 2 of number of bits) to release 625 * 626 * This is the complement to __bitmap_find_free_region() and releases 627 * the found region (by clearing it in the bitmap). 628 */ 629 static inline void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) 630 { 631 bitmap_clear(bitmap, pos, BIT(order)); 632 } 633 634 /** 635 * bitmap_allocate_region - allocate bitmap region 636 * @bitmap: array of unsigned longs corresponding to the bitmap 637 * @pos: beginning of bit region to allocate 638 * @order: region size (log base 2 of number of bits) to allocate 639 * 640 * Allocate (set bits in) a specified region of a bitmap. 641 * 642 * Returns: 0 on success, or %-EBUSY if specified region wasn't 643 * free (not all bits were zero). 644 */ 645 static inline int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) 646 { 647 unsigned int len = BIT(order); 648 649 if (find_next_bit(bitmap, pos + len, pos) < pos + len) 650 return -EBUSY; 651 bitmap_set(bitmap, pos, len); 652 return 0; 653 } 654 655 /** 656 * bitmap_find_free_region - find a contiguous aligned mem region 657 * @bitmap: array of unsigned longs corresponding to the bitmap 658 * @bits: number of bits in the bitmap 659 * @order: region size (log base 2 of number of bits) to find 660 * 661 * Find a region of free (zero) bits in a @bitmap of @bits bits and 662 * allocate them (set them to one). Only consider regions of length 663 * a power (@order) of two, aligned to that power of two, which 664 * makes the search algorithm much faster. 665 * 666 * Returns: the bit offset in bitmap of the allocated region, 667 * or -errno on failure. 668 */ 669 static inline int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order) 670 { 671 unsigned int pos, end; /* scans bitmap by regions of size order */ 672 673 for (pos = 0; (end = pos + BIT(order)) <= bits; pos = end) { 674 if (!bitmap_allocate_region(bitmap, pos, order)) 675 return pos; 676 } 677 return -ENOMEM; 678 } 679 680 /** 681 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap. 682 * @n: u64 value 683 * 684 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit 685 * integers in 32-bit environment, and 64-bit integers in 64-bit one. 686 * 687 * There are four combinations of endianness and length of the word in linux 688 * ABIs: LE64, BE64, LE32 and BE32. 689 * 690 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in 691 * bitmaps and therefore don't require any special handling. 692 * 693 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory 694 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the 695 * other hand is represented as an array of 32-bit words and the position of 696 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that 697 * word. For example, bit #42 is located at 10th position of 2nd word. 698 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit 699 * values in memory as it usually does. But for BE we need to swap hi and lo 700 * words manually. 701 * 702 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and 703 * lo parts of u64. For LE32 it does nothing, and for BE environment it swaps 704 * hi and lo words, as is expected by bitmap. 705 */ 706 #if __BITS_PER_LONG == 64 707 #define BITMAP_FROM_U64(n) (n) 708 #else 709 #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \ 710 ((unsigned long) ((u64)(n) >> 32)) 711 #endif 712 713 /** 714 * bitmap_from_u64 - Check and swap words within u64. 715 * @mask: source bitmap 716 * @dst: destination bitmap 717 * 718 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]`` 719 * to read u64 mask, we will get the wrong word. 720 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits, 721 * but we expect the lower 32-bits of u64. 722 */ 723 static inline void bitmap_from_u64(unsigned long *dst, u64 mask) 724 { 725 bitmap_from_arr64(dst, &mask, 64); 726 } 727 728 /** 729 * bitmap_get_value8 - get an 8-bit value within a memory region 730 * @map: address to the bitmap memory region 731 * @start: bit offset of the 8-bit value; must be a multiple of 8 732 * 733 * Returns the 8-bit value located at the @start bit offset within the @src 734 * memory region. 735 */ 736 static inline unsigned long bitmap_get_value8(const unsigned long *map, 737 unsigned long start) 738 { 739 const size_t index = BIT_WORD(start); 740 const unsigned long offset = start % BITS_PER_LONG; 741 742 return (map[index] >> offset) & 0xFF; 743 } 744 745 /** 746 * bitmap_set_value8 - set an 8-bit value within a memory region 747 * @map: address to the bitmap memory region 748 * @value: the 8-bit value; values wider than 8 bits may clobber bitmap 749 * @start: bit offset of the 8-bit value; must be a multiple of 8 750 */ 751 static inline void bitmap_set_value8(unsigned long *map, unsigned long value, 752 unsigned long start) 753 { 754 const size_t index = BIT_WORD(start); 755 const unsigned long offset = start % BITS_PER_LONG; 756 757 map[index] &= ~(0xFFUL << offset); 758 map[index] |= value << offset; 759 } 760 761 /** 762 * bitmap_read - read a value of n-bits from the memory region 763 * @map: address to the bitmap memory region 764 * @start: bit offset of the n-bit value 765 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG 766 * 767 * Returns: value of @nbits bits located at the @start bit offset within the 768 * @map memory region. For @nbits = 0 and @nbits > BITS_PER_LONG the return 769 * value is undefined. 770 */ 771 static inline unsigned long bitmap_read(const unsigned long *map, 772 unsigned long start, 773 unsigned long nbits) 774 { 775 size_t index = BIT_WORD(start); 776 unsigned long offset = start % BITS_PER_LONG; 777 unsigned long space = BITS_PER_LONG - offset; 778 unsigned long value_low, value_high; 779 780 if (unlikely(!nbits || nbits > BITS_PER_LONG)) 781 return 0; 782 783 if (space >= nbits) 784 return (map[index] >> offset) & BITMAP_LAST_WORD_MASK(nbits); 785 786 value_low = map[index] & BITMAP_FIRST_WORD_MASK(start); 787 value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits); 788 return (value_low >> offset) | (value_high << space); 789 } 790 791 /** 792 * bitmap_write - write n-bit value within a memory region 793 * @map: address to the bitmap memory region 794 * @value: value to write, clamped to nbits 795 * @start: bit offset of the n-bit value 796 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG. 797 * 798 * bitmap_write() behaves as-if implemented as @nbits calls of __assign_bit(), 799 * i.e. bits beyond @nbits are ignored: 800 * 801 * for (bit = 0; bit < nbits; bit++) 802 * __assign_bit(start + bit, bitmap, val & BIT(bit)); 803 * 804 * For @nbits == 0 and @nbits > BITS_PER_LONG no writes are performed. 805 */ 806 static inline void bitmap_write(unsigned long *map, unsigned long value, 807 unsigned long start, unsigned long nbits) 808 { 809 size_t index; 810 unsigned long offset; 811 unsigned long space; 812 unsigned long mask; 813 bool fit; 814 815 if (unlikely(!nbits || nbits > BITS_PER_LONG)) 816 return; 817 818 mask = BITMAP_LAST_WORD_MASK(nbits); 819 value &= mask; 820 offset = start % BITS_PER_LONG; 821 space = BITS_PER_LONG - offset; 822 fit = space >= nbits; 823 index = BIT_WORD(start); 824 825 map[index] &= (fit ? (~(mask << offset)) : ~BITMAP_FIRST_WORD_MASK(start)); 826 map[index] |= value << offset; 827 if (fit) 828 return; 829 830 map[index + 1] &= BITMAP_FIRST_WORD_MASK(start + nbits); 831 map[index + 1] |= (value >> space); 832 } 833 834 #endif /* __ASSEMBLY__ */ 835 836 #endif /* __LINUX_BITMAP_H */ 837