linux/include/linux/bitmap.h
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   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/limits.h>
  10#include <linux/string.h>
  11#include <linux/types.h>
  12
  13struct device;
  14
  15/*
  16 * bitmaps provide bit arrays that consume one or more unsigned
  17 * longs.  The bitmap interface and available operations are listed
  18 * here, in bitmap.h
  19 *
  20 * Function implementations generic to all architectures are in
  21 * lib/bitmap.c.  Functions implementations that are architecture
  22 * specific are in various include/asm-<arch>/bitops.h headers
  23 * and other arch/<arch> specific files.
  24 *
  25 * See lib/bitmap.c for more details.
  26 */
  27
  28/**
  29 * DOC: bitmap overview
  30 *
  31 * The available bitmap operations and their rough meaning in the
  32 * case that the bitmap is a single unsigned long are thus:
  33 *
  34 * The generated code is more efficient when nbits is known at
  35 * compile-time and at most BITS_PER_LONG.
  36 *
  37 * ::
  38 *
  39 *  bitmap_zero(dst, nbits)                     *dst = 0UL
  40 *  bitmap_fill(dst, nbits)                     *dst = ~0UL
  41 *  bitmap_copy(dst, src, nbits)                *dst = *src
  42 *  bitmap_and(dst, src1, src2, nbits)          *dst = *src1 & *src2
  43 *  bitmap_or(dst, src1, src2, nbits)           *dst = *src1 | *src2
  44 *  bitmap_xor(dst, src1, src2, nbits)          *dst = *src1 ^ *src2
  45 *  bitmap_andnot(dst, src1, src2, nbits)       *dst = *src1 & ~(*src2)
  46 *  bitmap_complement(dst, src, nbits)          *dst = ~(*src)
  47 *  bitmap_equal(src1, src2, nbits)             Are *src1 and *src2 equal?
  48 *  bitmap_intersects(src1, src2, nbits)        Do *src1 and *src2 overlap?
  49 *  bitmap_subset(src1, src2, nbits)            Is *src1 a subset of *src2?
  50 *  bitmap_empty(src, nbits)                    Are all bits zero in *src?
  51 *  bitmap_full(src, nbits)                     Are all bits set in *src?
  52 *  bitmap_weight(src, nbits)                   Hamming Weight: number set bits
  53 *  bitmap_set(dst, pos, nbits)                 Set specified bit area
  54 *  bitmap_clear(dst, pos, nbits)               Clear specified bit area
  55 *  bitmap_find_next_zero_area(buf, len, pos, n, mask)  Find bit free area
  56 *  bitmap_find_next_zero_area_off(buf, len, pos, n, mask, mask_off)  as above
  57 *  bitmap_next_clear_region(map, &start, &end, nbits)  Find next clear region
  58 *  bitmap_next_set_region(map, &start, &end, nbits)  Find next set region
  59 *  bitmap_for_each_clear_region(map, rs, re, start, end)
  60 *                                              Iterate over all clear regions
  61 *  bitmap_for_each_set_region(map, rs, re, start, end)
  62 *                                              Iterate over all set regions
  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_remap(dst, src, old, new, nbits)     *dst = map(old, new)(src)
  68 *  bitmap_bitremap(oldbit, old, new, nbits)    newbit = map(old, new)(oldbit)
  69 *  bitmap_onto(dst, orig, relmap, nbits)       *dst = orig relative to relmap
  70 *  bitmap_fold(dst, orig, sz, nbits)           dst bits = orig bits mod sz
  71 *  bitmap_parse(buf, buflen, dst, nbits)       Parse bitmap dst from kernel buf
  72 *  bitmap_parse_user(ubuf, ulen, dst, nbits)   Parse bitmap dst from user buf
  73 *  bitmap_parselist(buf, dst, nbits)           Parse bitmap dst from kernel buf
  74 *  bitmap_parselist_user(buf, dst, nbits)      Parse bitmap dst from user buf
  75 *  bitmap_find_free_region(bitmap, bits, order)  Find and allocate bit region
  76 *  bitmap_release_region(bitmap, pos, order)   Free specified bit region
  77 *  bitmap_allocate_region(bitmap, pos, order)  Allocate specified bit region
  78 *  bitmap_from_arr32(dst, buf, nbits)          Copy nbits from u32[] buf to dst
  79 *  bitmap_to_arr32(buf, src, nbits)            Copy nbits from buf to u32[] dst
  80 *  bitmap_get_value8(map, start)               Get 8bit value from map at start
  81 *  bitmap_set_value8(map, value, start)        Set 8bit value to map at start
  82 *
  83 * Note, bitmap_zero() and bitmap_fill() operate over the region of
  84 * unsigned longs, that is, bits behind bitmap till the unsigned long
  85 * boundary will be zeroed or filled as well. Consider to use
  86 * bitmap_clear() or bitmap_set() to make explicit zeroing or filling
  87 * respectively.
  88 */
  89
  90/**
  91 * DOC: bitmap bitops
  92 *
  93 * Also the following operations in asm/bitops.h apply to bitmaps.::
  94 *
  95 *  set_bit(bit, addr)                  *addr |= bit
  96 *  clear_bit(bit, addr)                *addr &= ~bit
  97 *  change_bit(bit, addr)               *addr ^= bit
  98 *  test_bit(bit, addr)                 Is bit set in *addr?
  99 *  test_and_set_bit(bit, addr)         Set bit and return old value
 100 *  test_and_clear_bit(bit, addr)       Clear bit and return old value
 101 *  test_and_change_bit(bit, addr)      Change bit and return old value
 102 *  find_first_zero_bit(addr, nbits)    Position first zero bit in *addr
 103 *  find_first_bit(addr, nbits)         Position first set bit in *addr
 104 *  find_next_zero_bit(addr, nbits, bit)
 105 *                                      Position next zero bit in *addr >= bit
 106 *  find_next_bit(addr, nbits, bit)     Position next set bit in *addr >= bit
 107 *  find_next_and_bit(addr1, addr2, nbits, bit)
 108 *                                      Same as find_next_bit, but in
 109 *                                      (*addr1 & *addr2)
 110 *
 111 */
 112
 113/**
 114 * DOC: declare bitmap
 115 * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
 116 * to declare an array named 'name' of just enough unsigned longs to
 117 * contain all bit positions from 0 to 'bits' - 1.
 118 */
 119
 120/*
 121 * Allocation and deallocation of bitmap.
 122 * Provided in lib/bitmap.c to avoid circular dependency.
 123 */
 124unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
 125unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
 126unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node);
 127unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node);
 128void bitmap_free(const unsigned long *bitmap);
 129
 130/* Managed variants of the above. */
 131unsigned long *devm_bitmap_alloc(struct device *dev,
 132                                 unsigned int nbits, gfp_t flags);
 133unsigned long *devm_bitmap_zalloc(struct device *dev,
 134                                  unsigned int nbits, gfp_t flags);
 135
 136/*
 137 * lib/bitmap.c provides these functions:
 138 */
 139
 140int __bitmap_equal(const unsigned long *bitmap1,
 141                   const unsigned long *bitmap2, unsigned int nbits);
 142bool __pure __bitmap_or_equal(const unsigned long *src1,
 143                              const unsigned long *src2,
 144                              const unsigned long *src3,
 145                              unsigned int nbits);
 146void __bitmap_complement(unsigned long *dst, const unsigned long *src,
 147                         unsigned int nbits);
 148void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
 149                          unsigned int shift, unsigned int nbits);
 150void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
 151                         unsigned int shift, unsigned int nbits);
 152void bitmap_cut(unsigned long *dst, const unsigned long *src,
 153                unsigned int first, unsigned int cut, unsigned int nbits);
 154int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
 155                 const unsigned long *bitmap2, unsigned int nbits);
 156void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
 157                 const unsigned long *bitmap2, unsigned int nbits);
 158void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
 159                  const unsigned long *bitmap2, unsigned int nbits);
 160int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
 161                    const unsigned long *bitmap2, unsigned int nbits);
 162void __bitmap_replace(unsigned long *dst,
 163                      const unsigned long *old, const unsigned long *new,
 164                      const unsigned long *mask, unsigned int nbits);
 165int __bitmap_intersects(const unsigned long *bitmap1,
 166                        const unsigned long *bitmap2, unsigned int nbits);
 167int __bitmap_subset(const unsigned long *bitmap1,
 168                    const unsigned long *bitmap2, unsigned int nbits);
 169int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
 170void __bitmap_set(unsigned long *map, unsigned int start, int len);
 171void __bitmap_clear(unsigned long *map, unsigned int start, int len);
 172
 173unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
 174                                             unsigned long size,
 175                                             unsigned long start,
 176                                             unsigned int nr,
 177                                             unsigned long align_mask,
 178                                             unsigned long align_offset);
 179
 180/**
 181 * bitmap_find_next_zero_area - find a contiguous aligned zero area
 182 * @map: The address to base the search on
 183 * @size: The bitmap size in bits
 184 * @start: The bitnumber to start searching at
 185 * @nr: The number of zeroed bits we're looking for
 186 * @align_mask: Alignment mask for zero area
 187 *
 188 * The @align_mask should be one less than a power of 2; the effect is that
 189 * the bit offset of all zero areas this function finds is multiples of that
 190 * power of 2. A @align_mask of 0 means no alignment is required.
 191 */
 192static inline unsigned long
 193bitmap_find_next_zero_area(unsigned long *map,
 194                           unsigned long size,
 195                           unsigned long start,
 196                           unsigned int nr,
 197                           unsigned long align_mask)
 198{
 199        return bitmap_find_next_zero_area_off(map, size, start, nr,
 200                                              align_mask, 0);
 201}
 202
 203int bitmap_parse(const char *buf, unsigned int buflen,
 204                        unsigned long *dst, int nbits);
 205int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
 206                        unsigned long *dst, int nbits);
 207int bitmap_parselist(const char *buf, unsigned long *maskp,
 208                        int nmaskbits);
 209int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
 210                        unsigned long *dst, int nbits);
 211void bitmap_remap(unsigned long *dst, const unsigned long *src,
 212                const unsigned long *old, const unsigned long *new, unsigned int nbits);
 213int bitmap_bitremap(int oldbit,
 214                const unsigned long *old, const unsigned long *new, int bits);
 215void bitmap_onto(unsigned long *dst, const unsigned long *orig,
 216                const unsigned long *relmap, unsigned int bits);
 217void bitmap_fold(unsigned long *dst, const unsigned long *orig,
 218                unsigned int sz, unsigned int nbits);
 219int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order);
 220void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order);
 221int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order);
 222
 223#ifdef __BIG_ENDIAN
 224void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits);
 225#else
 226#define bitmap_copy_le bitmap_copy
 227#endif
 228unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int ord, unsigned int nbits);
 229int bitmap_print_to_pagebuf(bool list, char *buf,
 230                                   const unsigned long *maskp, int nmaskbits);
 231
 232extern int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
 233                                      int nmaskbits, loff_t off, size_t count);
 234
 235extern int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
 236                                      int nmaskbits, loff_t off, size_t count);
 237
 238#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
 239#define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
 240
 241static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
 242{
 243        unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 244        memset(dst, 0, len);
 245}
 246
 247static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
 248{
 249        unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 250        memset(dst, 0xff, len);
 251}
 252
 253static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
 254                        unsigned int nbits)
 255{
 256        unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 257        memcpy(dst, src, len);
 258}
 259
 260/*
 261 * Copy bitmap and clear tail bits in last word.
 262 */
 263static 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, and
 273 * therefore conversion is not needed when copying data from/to arrays of u32.
 274 */
 275#if BITS_PER_LONG == 64
 276void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,
 277                                                        unsigned int nbits);
 278void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,
 279                                                        unsigned int nbits);
 280#else
 281#define bitmap_from_arr32(bitmap, buf, nbits)                   \
 282        bitmap_copy_clear_tail((unsigned long *) (bitmap),      \
 283                        (const unsigned long *) (buf), (nbits))
 284#define bitmap_to_arr32(buf, bitmap, nbits)                     \
 285        bitmap_copy_clear_tail((unsigned long *) (buf),         \
 286                        (const unsigned long *) (bitmap), (nbits))
 287#endif
 288
 289static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
 290                        const unsigned long *src2, unsigned int nbits)
 291{
 292        if (small_const_nbits(nbits))
 293                return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 294        return __bitmap_and(dst, src1, src2, nbits);
 295}
 296
 297static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
 298                        const unsigned long *src2, unsigned int nbits)
 299{
 300        if (small_const_nbits(nbits))
 301                *dst = *src1 | *src2;
 302        else
 303                __bitmap_or(dst, src1, src2, nbits);
 304}
 305
 306static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
 307                        const unsigned long *src2, unsigned int nbits)
 308{
 309        if (small_const_nbits(nbits))
 310                *dst = *src1 ^ *src2;
 311        else
 312                __bitmap_xor(dst, src1, src2, nbits);
 313}
 314
 315static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
 316                        const unsigned long *src2, unsigned int nbits)
 317{
 318        if (small_const_nbits(nbits))
 319                return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 320        return __bitmap_andnot(dst, src1, src2, nbits);
 321}
 322
 323static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
 324                        unsigned int nbits)
 325{
 326        if (small_const_nbits(nbits))
 327                *dst = ~(*src);
 328        else
 329                __bitmap_complement(dst, src, nbits);
 330}
 331
 332#ifdef __LITTLE_ENDIAN
 333#define BITMAP_MEM_ALIGNMENT 8
 334#else
 335#define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
 336#endif
 337#define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)
 338
 339static inline int bitmap_equal(const unsigned long *src1,
 340                        const unsigned long *src2, unsigned int nbits)
 341{
 342        if (small_const_nbits(nbits))
 343                return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
 344        if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 345            IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 346                return !memcmp(src1, src2, nbits / 8);
 347        return __bitmap_equal(src1, src2, nbits);
 348}
 349
 350/**
 351 * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third
 352 * @src1:       Pointer to bitmap 1
 353 * @src2:       Pointer to bitmap 2 will be or'ed with bitmap 1
 354 * @src3:       Pointer to bitmap 3. Compare to the result of *@src1 | *@src2
 355 * @nbits:      number of bits in each of these bitmaps
 356 *
 357 * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
 358 */
 359static inline bool bitmap_or_equal(const unsigned long *src1,
 360                                   const unsigned long *src2,
 361                                   const unsigned long *src3,
 362                                   unsigned int nbits)
 363{
 364        if (!small_const_nbits(nbits))
 365                return __bitmap_or_equal(src1, src2, src3, nbits);
 366
 367        return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
 368}
 369
 370static inline int bitmap_intersects(const unsigned long *src1,
 371                        const unsigned long *src2, unsigned int nbits)
 372{
 373        if (small_const_nbits(nbits))
 374                return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 375        else
 376                return __bitmap_intersects(src1, src2, nbits);
 377}
 378
 379static inline int bitmap_subset(const unsigned long *src1,
 380                        const unsigned long *src2, unsigned int nbits)
 381{
 382        if (small_const_nbits(nbits))
 383                return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
 384        else
 385                return __bitmap_subset(src1, src2, nbits);
 386}
 387
 388static inline bool bitmap_empty(const unsigned long *src, unsigned nbits)
 389{
 390        if (small_const_nbits(nbits))
 391                return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
 392
 393        return find_first_bit(src, nbits) == nbits;
 394}
 395
 396static inline bool bitmap_full(const unsigned long *src, unsigned int nbits)
 397{
 398        if (small_const_nbits(nbits))
 399                return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
 400
 401        return find_first_zero_bit(src, nbits) == nbits;
 402}
 403
 404static __always_inline int bitmap_weight(const unsigned long *src, unsigned int nbits)
 405{
 406        if (small_const_nbits(nbits))
 407                return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
 408        return __bitmap_weight(src, nbits);
 409}
 410
 411static __always_inline void bitmap_set(unsigned long *map, unsigned int start,
 412                unsigned int nbits)
 413{
 414        if (__builtin_constant_p(nbits) && nbits == 1)
 415                __set_bit(start, map);
 416        else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
 417                 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
 418                 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 419                 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 420                memset((char *)map + start / 8, 0xff, nbits / 8);
 421        else
 422                __bitmap_set(map, start, nbits);
 423}
 424
 425static __always_inline void bitmap_clear(unsigned long *map, unsigned int start,
 426                unsigned int nbits)
 427{
 428        if (__builtin_constant_p(nbits) && nbits == 1)
 429                __clear_bit(start, map);
 430        else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
 431                 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
 432                 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 433                 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 434                memset((char *)map + start / 8, 0, nbits / 8);
 435        else
 436                __bitmap_clear(map, start, nbits);
 437}
 438
 439static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src,
 440                                unsigned int shift, unsigned int nbits)
 441{
 442        if (small_const_nbits(nbits))
 443                *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;
 444        else
 445                __bitmap_shift_right(dst, src, shift, nbits);
 446}
 447
 448static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src,
 449                                unsigned int shift, unsigned int nbits)
 450{
 451        if (small_const_nbits(nbits))
 452                *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits);
 453        else
 454                __bitmap_shift_left(dst, src, shift, nbits);
 455}
 456
 457static inline void bitmap_replace(unsigned long *dst,
 458                                  const unsigned long *old,
 459                                  const unsigned long *new,
 460                                  const unsigned long *mask,
 461                                  unsigned int nbits)
 462{
 463        if (small_const_nbits(nbits))
 464                *dst = (*old & ~(*mask)) | (*new & *mask);
 465        else
 466                __bitmap_replace(dst, old, new, mask, nbits);
 467}
 468
 469static inline void bitmap_next_clear_region(unsigned long *bitmap,
 470                                            unsigned int *rs, unsigned int *re,
 471                                            unsigned int end)
 472{
 473        *rs = find_next_zero_bit(bitmap, end, *rs);
 474        *re = find_next_bit(bitmap, end, *rs + 1);
 475}
 476
 477static inline void bitmap_next_set_region(unsigned long *bitmap,
 478                                          unsigned int *rs, unsigned int *re,
 479                                          unsigned int end)
 480{
 481        *rs = find_next_bit(bitmap, end, *rs);
 482        *re = find_next_zero_bit(bitmap, end, *rs + 1);
 483}
 484
 485/*
 486 * Bitmap region iterators.  Iterates over the bitmap between [@start, @end).
 487 * @rs and @re should be integer variables and will be set to start and end
 488 * index of the current clear or set region.
 489 */
 490#define bitmap_for_each_clear_region(bitmap, rs, re, start, end)             \
 491        for ((rs) = (start),                                                 \
 492             bitmap_next_clear_region((bitmap), &(rs), &(re), (end));        \
 493             (rs) < (re);                                                    \
 494             (rs) = (re) + 1,                                                \
 495             bitmap_next_clear_region((bitmap), &(rs), &(re), (end)))
 496
 497#define bitmap_for_each_set_region(bitmap, rs, re, start, end)               \
 498        for ((rs) = (start),                                                 \
 499             bitmap_next_set_region((bitmap), &(rs), &(re), (end));          \
 500             (rs) < (re);                                                    \
 501             (rs) = (re) + 1,                                                \
 502             bitmap_next_set_region((bitmap), &(rs), &(re), (end)))
 503
 504/**
 505 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
 506 * @n: u64 value
 507 *
 508 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit
 509 * integers in 32-bit environment, and 64-bit integers in 64-bit one.
 510 *
 511 * There are four combinations of endianness and length of the word in linux
 512 * ABIs: LE64, BE64, LE32 and BE32.
 513 *
 514 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in
 515 * bitmaps and therefore don't require any special handling.
 516 *
 517 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory
 518 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the
 519 * other hand is represented as an array of 32-bit words and the position of
 520 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that
 521 * word.  For example, bit #42 is located at 10th position of 2nd word.
 522 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit
 523 * values in memory as it usually does. But for BE we need to swap hi and lo
 524 * words manually.
 525 *
 526 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and
 527 * lo parts of u64.  For LE32 it does nothing, and for BE environment it swaps
 528 * hi and lo words, as is expected by bitmap.
 529 */
 530#if __BITS_PER_LONG == 64
 531#define BITMAP_FROM_U64(n) (n)
 532#else
 533#define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \
 534                                ((unsigned long) ((u64)(n) >> 32))
 535#endif
 536
 537/**
 538 * bitmap_from_u64 - Check and swap words within u64.
 539 *  @mask: source bitmap
 540 *  @dst:  destination bitmap
 541 *
 542 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``
 543 * to read u64 mask, we will get the wrong word.
 544 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,
 545 * but we expect the lower 32-bits of u64.
 546 */
 547static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
 548{
 549        dst[0] = mask & ULONG_MAX;
 550
 551        if (sizeof(mask) > sizeof(unsigned long))
 552                dst[1] = mask >> 32;
 553}
 554
 555/**
 556 * bitmap_get_value8 - get an 8-bit value within a memory region
 557 * @map: address to the bitmap memory region
 558 * @start: bit offset of the 8-bit value; must be a multiple of 8
 559 *
 560 * Returns the 8-bit value located at the @start bit offset within the @src
 561 * memory region.
 562 */
 563static inline unsigned long bitmap_get_value8(const unsigned long *map,
 564                                              unsigned long start)
 565{
 566        const size_t index = BIT_WORD(start);
 567        const unsigned long offset = start % BITS_PER_LONG;
 568
 569        return (map[index] >> offset) & 0xFF;
 570}
 571
 572/**
 573 * bitmap_set_value8 - set an 8-bit value within a memory region
 574 * @map: address to the bitmap memory region
 575 * @value: the 8-bit value; values wider than 8 bits may clobber bitmap
 576 * @start: bit offset of the 8-bit value; must be a multiple of 8
 577 */
 578static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
 579                                     unsigned long start)
 580{
 581        const size_t index = BIT_WORD(start);
 582        const unsigned long offset = start % BITS_PER_LONG;
 583
 584        map[index] &= ~(0xFFUL << offset);
 585        map[index] |= value << offset;
 586}
 587
 588#endif /* __ASSEMBLY__ */
 589
 590#endif /* __LINUX_BITMAP_H */
 591