include/linux/bitmap.h

   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
  13 struct 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  */
 124 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
 125 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
 126 void bitmap_free(const unsigned long *bitmap);
 127
 128 /* Managed variants of the above. */
 129 unsigned long *devm_bitmap_alloc(struct device *dev,
 130                                  unsigned int nbits, gfp_t flags);
 131 unsigned long *devm_bitmap_zalloc(struct device *dev,
 132                                   unsigned int nbits, gfp_t flags);
 133
 134 /*
 135  * lib/bitmap.c provides these functions:
 136  */
 137
 138 int __bitmap_equal(const unsigned long *bitmap1,
 139                    const unsigned long *bitmap2, unsigned int nbits);
 140 bool __pure __bitmap_or_equal(const unsigned long *src1,
 141                               const unsigned long *src2,
 142                               const unsigned long *src3,
 143                               unsigned int nbits);
 144 void __bitmap_complement(unsigned long *dst, const unsigned long *src,
 145                          unsigned int nbits);
 146 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
 147                           unsigned int shift, unsigned int nbits);
 148 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
 149                          unsigned int shift, unsigned int nbits);
 150 void bitmap_cut(unsigned long *dst, const unsigned long *src,
 151                 unsigned int first, unsigned int cut, unsigned int nbits);
 152 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
 153                  const unsigned long *bitmap2, unsigned int nbits);
 154 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
 155                  const unsigned long *bitmap2, unsigned int nbits);
 156 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
 157                   const unsigned long *bitmap2, unsigned int nbits);
 158 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
 159                     const unsigned long *bitmap2, unsigned int nbits);
 160 void __bitmap_replace(unsigned long *dst,
 161                       const unsigned long *old, const unsigned long *new,
 162                       const unsigned long *mask, unsigned int nbits);
 163 int __bitmap_intersects(const unsigned long *bitmap1,
 164                         const unsigned long *bitmap2, unsigned int nbits);
 165 int __bitmap_subset(const unsigned long *bitmap1,
 166                     const unsigned long *bitmap2, unsigned int nbits);
 167 int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
 168 void __bitmap_set(unsigned long *map, unsigned int start, int len);
 169 void __bitmap_clear(unsigned long *map, unsigned int start, int len);
 170
 171 unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
 172                                              unsigned long size,
 173                                              unsigned long start,
 174                                              unsigned int nr,
 175                                              unsigned long align_mask,
 176                                              unsigned long align_offset);
 177
 178 /**
 179  * bitmap_find_next_zero_area - find a contiguous aligned zero area
 180  * @map: The address to base the search on
 181  * @size: The bitmap size in bits
 182  * @start: The bitnumber to start searching at
 183  * @nr: The number of zeroed bits we're looking for
 184  * @align_mask: Alignment mask for zero area
 185  *
 186  * The @align_mask should be one less than a power of 2; the effect is that
 187  * the bit offset of all zero areas this function finds is multiples of that
 188  * power of 2. A @align_mask of 0 means no alignment is required.
 189  */
 190 static inline unsigned long
 191 bitmap_find_next_zero_area(unsigned long *map,
 192                            unsigned long size,
 193                            unsigned long start,
 194                            unsigned int nr,
 195                            unsigned long align_mask)
 196 {
 197         return bitmap_find_next_zero_area_off(map, size, start, nr,
 198                                               align_mask, 0);
 199 }
 200
 201 int bitmap_parse(const char *buf, unsigned int buflen,
 202                         unsigned long *dst, int nbits);
 203 int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
 204                         unsigned long *dst, int nbits);
 205 int bitmap_parselist(const char *buf, unsigned long *maskp,
 206                         int nmaskbits);
 207 int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
 208                         unsigned long *dst, int nbits);
 209 void bitmap_remap(unsigned long *dst, const unsigned long *src,
 210                 const unsigned long *old, const unsigned long *new, unsigned int nbits);
 211 int bitmap_bitremap(int oldbit,
 212                 const unsigned long *old, const unsigned long *new, int bits);
 213 void bitmap_onto(unsigned long *dst, const unsigned long *orig,
 214                 const unsigned long *relmap, unsigned int bits);
 215 void bitmap_fold(unsigned long *dst, const unsigned long *orig,
 216                 unsigned int sz, unsigned int nbits);
 217 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order);
 218 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order);
 219 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order);
 220
 221 #ifdef __BIG_ENDIAN
 222 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits);
 223 #else
 224 #define bitmap_copy_le bitmap_copy
 225 #endif
 226 unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int ord, unsigned int nbits);
 227 int bitmap_print_to_pagebuf(bool list, char *buf,
 228                                    const unsigned long *maskp, int nmaskbits);
 229
 230 extern int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
 231                                       int nmaskbits, loff_t off, size_t count);
 232
 233 extern int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
 234                                       int nmaskbits, loff_t off, size_t count);
 235
 236 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
 237 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
 238
 239 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
 240 {
 241         unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 242         memset(dst, 0, len);
 243 }
 244
 245 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
 246 {
 247         unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 248         memset(dst, 0xff, len);
 249 }
 250
 251 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
 252                         unsigned int nbits)
 253 {
 254         unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 255         memcpy(dst, src, len);
 256 }
 257
 258 /*
 259  * Copy bitmap and clear tail bits in last word.
 260  */
 261 static inline void bitmap_copy_clear_tail(unsigned long *dst,
 262                 const unsigned long *src, unsigned int nbits)
 263 {
 264         bitmap_copy(dst, src, nbits);
 265         if (nbits % BITS_PER_LONG)
 266                 dst[nbits / BITS_PER_LONG] &= BITMAP_LAST_WORD_MASK(nbits);
 267 }
 268
 269 /*
 270  * On 32-bit systems bitmaps are represented as u32 arrays internally, and
 271  * therefore conversion is not needed when copying data from/to arrays of u32.
 272  */
 273 #if BITS_PER_LONG == 64
 274 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,
 275                                                         unsigned int nbits);
 276 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,
 277                                                         unsigned int nbits);
 278 #else
 279 #define bitmap_from_arr32(bitmap, buf, nbits)                   \
 280         bitmap_copy_clear_tail((unsigned long *) (bitmap),      \
 281                         (const unsigned long *) (buf), (nbits))
 282 #define bitmap_to_arr32(buf, bitmap, nbits)                     \
 283         bitmap_copy_clear_tail((unsigned long *) (buf),         \
 284                         (const unsigned long *) (bitmap), (nbits))
 285 #endif
 286
 287 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
 288                         const unsigned long *src2, unsigned int nbits)
 289 {
 290         if (small_const_nbits(nbits))
 291                 return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 292         return __bitmap_and(dst, src1, src2, nbits);
 293 }
 294
 295 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
 296                         const unsigned long *src2, unsigned int nbits)
 297 {
 298         if (small_const_nbits(nbits))
 299                 *dst = *src1 | *src2;
 300         else
 301                 __bitmap_or(dst, src1, src2, nbits);
 302 }
 303
 304 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
 305                         const unsigned long *src2, unsigned int nbits)
 306 {
 307         if (small_const_nbits(nbits))
 308                 *dst = *src1 ^ *src2;
 309         else
 310                 __bitmap_xor(dst, src1, src2, nbits);
 311 }
 312
 313 static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
 314                         const unsigned long *src2, unsigned int nbits)
 315 {
 316         if (small_const_nbits(nbits))
 317                 return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 318         return __bitmap_andnot(dst, src1, src2, nbits);
 319 }
 320
 321 static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
 322                         unsigned int nbits)
 323 {
 324         if (small_const_nbits(nbits))
 325                 *dst = ~(*src);
 326         else
 327                 __bitmap_complement(dst, src, nbits);
 328 }
 329
 330 #ifdef __LITTLE_ENDIAN
 331 #define BITMAP_MEM_ALIGNMENT 8
 332 #else
 333 #define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
 334 #endif
 335 #define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)
 336
 337 static inline int bitmap_equal(const unsigned long *src1,
 338                         const unsigned long *src2, unsigned int nbits)
 339 {
 340         if (small_const_nbits(nbits))
 341                 return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
 342         if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 343             IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 344                 return !memcmp(src1, src2, nbits / 8);
 345         return __bitmap_equal(src1, src2, nbits);
 346 }
 347
 348 /**
 349  * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third
 350  * @src1:       Pointer to bitmap 1
 351  * @src2:       Pointer to bitmap 2 will be or'ed with bitmap 1
 352  * @src3:       Pointer to bitmap 3. Compare to the result of *@src1 | *@src2
 353  * @nbits:      number of bits in each of these bitmaps
 354  *
 355  * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
 356  */
 357 static inline bool bitmap_or_equal(const unsigned long *src1,
 358                                    const unsigned long *src2,
 359                                    const unsigned long *src3,
 360                                    unsigned int nbits)
 361 {
 362         if (!small_const_nbits(nbits))
 363                 return __bitmap_or_equal(src1, src2, src3, nbits);
 364
 365         return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
 366 }
 367
 368 static inline int bitmap_intersects(const unsigned long *src1,
 369                         const unsigned long *src2, unsigned int nbits)
 370 {
 371         if (small_const_nbits(nbits))
 372                 return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 373         else
 374                 return __bitmap_intersects(src1, src2, nbits);
 375 }
 376
 377 static inline int bitmap_subset(const unsigned long *src1,
 378                         const unsigned long *src2, unsigned int nbits)
 379 {
 380         if (small_const_nbits(nbits))
 381                 return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
 382         else
 383                 return __bitmap_subset(src1, src2, nbits);
 384 }
 385
 386 static inline bool bitmap_empty(const unsigned long *src, unsigned nbits)
 387 {
 388         if (small_const_nbits(nbits))
 389                 return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
 390
 391         return find_first_bit(src, nbits) == nbits;
 392 }
 393
 394 static inline bool bitmap_full(const unsigned long *src, unsigned int nbits)
 395 {
 396         if (small_const_nbits(nbits))
 397                 return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
 398
 399         return find_first_zero_bit(src, nbits) == nbits;
 400 }
 401
 402 static __always_inline int bitmap_weight(const unsigned long *src, unsigned int nbits)
 403 {
 404         if (small_const_nbits(nbits))
 405                 return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
 406         return __bitmap_weight(src, nbits);
 407 }
 408
 409 static __always_inline void bitmap_set(unsigned long *map, unsigned int start,
 410                 unsigned int nbits)
 411 {
 412         if (__builtin_constant_p(nbits) && nbits == 1)
 413                 __set_bit(start, map);
 414         else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
 415                  IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
 416                  __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 417                  IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 418                 memset((char *)map + start / 8, 0xff, nbits / 8);
 419         else
 420                 __bitmap_set(map, start, nbits);
 421 }
 422
 423 static __always_inline void bitmap_clear(unsigned long *map, unsigned int start,
 424                 unsigned int nbits)
 425 {
 426         if (__builtin_constant_p(nbits) && nbits == 1)
 427                 __clear_bit(start, map);
 428         else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
 429                  IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
 430                  __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 431                  IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 432                 memset((char *)map + start / 8, 0, nbits / 8);
 433         else
 434                 __bitmap_clear(map, start, nbits);
 435 }
 436
 437 static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src,
 438                                 unsigned int shift, unsigned int nbits)
 439 {
 440         if (small_const_nbits(nbits))
 441                 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;
 442         else
 443                 __bitmap_shift_right(dst, src, shift, nbits);
 444 }
 445
 446 static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src,
 447                                 unsigned int shift, unsigned int nbits)
 448 {
 449         if (small_const_nbits(nbits))
 450                 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits);
 451         else
 452                 __bitmap_shift_left(dst, src, shift, nbits);
 453 }
 454
 455 static inline void bitmap_replace(unsigned long *dst,
 456                                   const unsigned long *old,
 457                                   const unsigned long *new,
 458                                   const unsigned long *mask,
 459                                   unsigned int nbits)
 460 {
 461         if (small_const_nbits(nbits))
 462                 *dst = (*old & ~(*mask)) | (*new & *mask);
 463         else
 464                 __bitmap_replace(dst, old, new, mask, nbits);
 465 }
 466
 467 static inline void bitmap_next_clear_region(unsigned long *bitmap,
 468                                             unsigned int *rs, unsigned int *re,
 469                                             unsigned int end)
 470 {
 471         *rs = find_next_zero_bit(bitmap, end, *rs);
 472         *re = find_next_bit(bitmap, end, *rs + 1);
 473 }
 474
 475 static inline void bitmap_next_set_region(unsigned long *bitmap,
 476                                           unsigned int *rs, unsigned int *re,
 477                                           unsigned int end)
 478 {
 479         *rs = find_next_bit(bitmap, end, *rs);
 480         *re = find_next_zero_bit(bitmap, end, *rs + 1);
 481 }
 482
 483 /*
 484  * Bitmap region iterators.  Iterates over the bitmap between [@start, @end).
 485  * @rs and @re should be integer variables and will be set to start and end
 486  * index of the current clear or set region.
 487  */
 488 #define bitmap_for_each_clear_region(bitmap, rs, re, start, end)             \
 489         for ((rs) = (start),                                                 \
 490              bitmap_next_clear_region((bitmap), &(rs), &(re), (end));        \
 491              (rs) < (re);                                                    \
 492              (rs) = (re) + 1,                                                \
 493              bitmap_next_clear_region((bitmap), &(rs), &(re), (end)))
 494
 495 #define bitmap_for_each_set_region(bitmap, rs, re, start, end)               \
 496         for ((rs) = (start),                                                 \
 497              bitmap_next_set_region((bitmap), &(rs), &(re), (end));          \
 498              (rs) < (re);                                                    \
 499              (rs) = (re) + 1,                                                \
 500              bitmap_next_set_region((bitmap), &(rs), &(re), (end)))
 501
 502 /**
 503  * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
 504  * @n: u64 value
 505  *
 506  * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit
 507  * integers in 32-bit environment, and 64-bit integers in 64-bit one.
 508  *
 509  * There are four combinations of endianness and length of the word in linux
 510  * ABIs: LE64, BE64, LE32 and BE32.
 511  *
 512  * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in
 513  * bitmaps and therefore don't require any special handling.
 514  *
 515  * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory
 516  * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the
 517  * other hand is represented as an array of 32-bit words and the position of
 518  * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that
 519  * word.  For example, bit #42 is located at 10th position of 2nd word.
 520  * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit
 521  * values in memory as it usually does. But for BE we need to swap hi and lo
 522  * words manually.
 523  *
 524  * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and
 525  * lo parts of u64.  For LE32 it does nothing, and for BE environment it swaps
 526  * hi and lo words, as is expected by bitmap.
 527  */
 528 #if __BITS_PER_LONG == 64
 529 #define BITMAP_FROM_U64(n) (n)
 530 #else
 531 #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \
 532                                 ((unsigned long) ((u64)(n) >> 32))
 533 #endif
 534
 535 /**
 536  * bitmap_from_u64 - Check and swap words within u64.
 537  *  @mask: source bitmap
 538  *  @dst:  destination bitmap
 539  *
 540  * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``
 541  * to read u64 mask, we will get the wrong word.
 542  * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,
 543  * but we expect the lower 32-bits of u64.
 544  */
 545 static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
 546 {
 547         dst[0] = mask & ULONG_MAX;
 548
 549         if (sizeof(mask) > sizeof(unsigned long))
 550                 dst[1] = mask >> 32;
 551 }
 552
 553 /**
 554  * bitmap_get_value8 - get an 8-bit value within a memory region
 555  * @map: address to the bitmap memory region
 556  * @start: bit offset of the 8-bit value; must be a multiple of 8
 557  *
 558  * Returns the 8-bit value located at the @start bit offset within the @src
 559  * memory region.
 560  */
 561 static inline unsigned long bitmap_get_value8(const unsigned long *map,
 562                                               unsigned long start)
 563 {
 564         const size_t index = BIT_WORD(start);
 565         const unsigned long offset = start % BITS_PER_LONG;
 566
 567         return (map[index] >> offset) & 0xFF;
 568 }
 569
 570 /**
 571  * bitmap_set_value8 - set an 8-bit value within a memory region
 572  * @map: address to the bitmap memory region
 573  * @value: the 8-bit value; values wider than 8 bits may clobber bitmap
 574  * @start: bit offset of the 8-bit value; must be a multiple of 8
 575  */
 576 static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
 577                                      unsigned long start)
 578 {
 579         const size_t index = BIT_WORD(start);
 580         const unsigned long offset = start % BITS_PER_LONG;
 581
 582         map[index] &= ~(0xFFUL << offset);
 583         map[index] |= value << offset;
 584 }
 585
 586 #endif /* __ASSEMBLY__ */
 587
 588 #endif /* __LINUX_BITMAP_H */