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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef __LINUX_BITMAP_H3#define __LINUX_BITMAP_H4 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 17struct device;18 19/*20 * bitmaps provide bit arrays that consume one or more unsigned21 * longs. The bitmap interface and available operations are listed22 * here, in bitmap.h23 *24 * Function implementations generic to all architectures are in25 * lib/bitmap.c. Functions implementations that are architecture26 * specific are in various include/asm-<arch>/bitops.h headers27 * and other arch/<arch> specific files.28 *29 * See lib/bitmap.c for more details.30 */31 32/**33 * DOC: bitmap overview34 *35 * The available bitmap operations and their rough meaning in the36 * case that the bitmap is a single unsigned long are thus:37 *38 * The generated code is more efficient when nbits is known at39 * compile-time and at most BITS_PER_LONG.40 *41 * ::42 *43 * bitmap_zero(dst, nbits) *dst = 0UL44 * bitmap_fill(dst, nbits) *dst = ~0UL45 * bitmap_copy(dst, src, nbits) *dst = *src46 * bitmap_and(dst, src1, src2, nbits) *dst = *src1 & *src247 * bitmap_or(dst, src1, src2, nbits) *dst = *src1 | *src248 * bitmap_xor(dst, src1, src2, nbits) *dst = *src1 ^ *src249 * 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 bits57 * bitmap_weight_and(src1, src2, nbits) Hamming Weight of and'ed bitmap58 * bitmap_weight_andnot(src1, src2, nbits) Hamming Weight of andnot'ed bitmap59 * bitmap_set(dst, pos, nbits) Set specified bit area60 * bitmap_clear(dst, pos, nbits) Clear specified bit area61 * bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area62 * bitmap_find_next_zero_area_off(buf, len, pos, n, mask, mask_off) as above63 * bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n64 * bitmap_shift_left(dst, src, n, nbits) *dst = *src << n65 * bitmap_cut(dst, src, first, n, nbits) Cut n bits from first, copy rest66 * 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 relmap72 * bitmap_fold(dst, orig, sz, nbits) dst bits = orig bits mod sz73 * bitmap_parse(buf, buflen, dst, nbits) Parse bitmap dst from kernel buf74 * bitmap_parse_user(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf75 * bitmap_parselist(buf, dst, nbits) Parse bitmap dst from kernel buf76 * bitmap_parselist_user(buf, dst, nbits) Parse bitmap dst from user buf77 * bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region78 * bitmap_release_region(bitmap, pos, order) Free specified bit region79 * bitmap_allocate_region(bitmap, pos, order) Allocate specified bit region80 * bitmap_from_arr32(dst, buf, nbits) Copy nbits from u32[] buf to dst81 * bitmap_from_arr64(dst, buf, nbits) Copy nbits from u64[] buf to dst82 * bitmap_to_arr32(buf, src, nbits) Copy nbits from buf to u32[] dst83 * bitmap_to_arr64(buf, src, nbits) Copy nbits from buf to u64[] dst84 * bitmap_get_value8(map, start) Get 8bit value from map at start85 * bitmap_set_value8(map, value, start) Set 8bit value to map at start86 * bitmap_read(map, start, nbits) Read an nbits-sized value from87 * map at start88 * bitmap_write(map, value, start, nbits) Write an nbits-sized value to89 * map at start90 *91 * Note, bitmap_zero() and bitmap_fill() operate over the region of92 * unsigned longs, that is, bits behind bitmap till the unsigned long93 * boundary will be zeroed or filled as well. Consider to use94 * bitmap_clear() or bitmap_set() to make explicit zeroing or filling95 * respectively.96 */97 98/**99 * DOC: bitmap bitops100 *101 * Also the following operations in asm/bitops.h apply to bitmaps.::102 *103 * set_bit(bit, addr) *addr |= bit104 * clear_bit(bit, addr) *addr &= ~bit105 * change_bit(bit, addr) *addr ^= bit106 * test_bit(bit, addr) Is bit set in *addr?107 * test_and_set_bit(bit, addr) Set bit and return old value108 * test_and_clear_bit(bit, addr) Clear bit and return old value109 * test_and_change_bit(bit, addr) Change bit and return old value110 * find_first_zero_bit(addr, nbits) Position first zero bit in *addr111 * find_first_bit(addr, nbits) Position first set bit in *addr112 * find_next_zero_bit(addr, nbits, bit)113 * Position next zero bit in *addr >= bit114 * find_next_bit(addr, nbits, bit) Position next set bit in *addr >= bit115 * find_next_and_bit(addr1, addr2, nbits, bit)116 * Same as find_next_bit, but in117 * (*addr1 & *addr2)118 *119 */120 121/**122 * DOC: declare bitmap123 * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used124 * to declare an array named 'name' of just enough unsigned longs to125 * 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 */132unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);133unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);134unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node);135unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node);136void bitmap_free(const unsigned long *bitmap);137 138DEFINE_FREE(bitmap, unsigned long *, if (_T) bitmap_free(_T))139 140/* Managed variants of the above. */141unsigned long *devm_bitmap_alloc(struct device *dev,142 unsigned int nbits, gfp_t flags);143unsigned 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 150bool __bitmap_equal(const unsigned long *bitmap1,151 const unsigned long *bitmap2, unsigned int nbits);152bool __pure __bitmap_or_equal(const unsigned long *src1,153 const unsigned long *src2,154 const unsigned long *src3,155 unsigned int nbits);156void __bitmap_complement(unsigned long *dst, const unsigned long *src,157 unsigned int nbits);158void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,159 unsigned int shift, unsigned int nbits);160void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,161 unsigned int shift, unsigned int nbits);162void bitmap_cut(unsigned long *dst, const unsigned long *src,163 unsigned int first, unsigned int cut, unsigned int nbits);164bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,165 const unsigned long *bitmap2, unsigned int nbits);166void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,167 const unsigned long *bitmap2, unsigned int nbits);168void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,169 const unsigned long *bitmap2, unsigned int nbits);170bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,171 const unsigned long *bitmap2, unsigned int nbits);172void __bitmap_replace(unsigned long *dst,173 const unsigned long *old, const unsigned long *new,174 const unsigned long *mask, unsigned int nbits);175bool __bitmap_intersects(const unsigned long *bitmap1,176 const unsigned long *bitmap2, unsigned int nbits);177bool __bitmap_subset(const unsigned long *bitmap1,178 const unsigned long *bitmap2, unsigned int nbits);179unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);180unsigned int __bitmap_weight_and(const unsigned long *bitmap1,181 const unsigned long *bitmap2, unsigned int nbits);182unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1,183 const unsigned long *bitmap2, unsigned int nbits);184void __bitmap_set(unsigned long *map, unsigned int start, int len);185void __bitmap_clear(unsigned long *map, unsigned int start, int len);186 187unsigned 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 area196 * @map: The address to base the search on197 * @size: The bitmap size in bits198 * @start: The bitnumber to start searching at199 * @nr: The number of zeroed bits we're looking for200 * @align_mask: Alignment mask for zero area201 *202 * The @align_mask should be one less than a power of 2; the effect is that203 * the bit offset of all zero areas this function finds is multiples of that204 * power of 2. A @align_mask of 0 means no alignment is required.205 */206static __always_inline207unsigned 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 217void bitmap_remap(unsigned long *dst, const unsigned long *src,218 const unsigned long *old, const unsigned long *new, unsigned int nbits);219int bitmap_bitremap(int oldbit,220 const unsigned long *old, const unsigned long *new, int bits);221void bitmap_onto(unsigned long *dst, const unsigned long *orig,222 const unsigned long *relmap, unsigned int bits);223void 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 231static __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 else238 memset(dst, 0, len);239}240 241static __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 else248 memset(dst, 0xff, len);249}250 251static __always_inline252void 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 else259 memcpy(dst, src, len);260}261 262/*263 * Copy bitmap and clear tail bits in last word.264 */265static __always_inline266void 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 273static inline void bitmap_copy_and_extend(unsigned long *to,274 const unsigned long *from,275 unsigned int count, unsigned int size)276{277 unsigned int copy = BITS_TO_LONGS(count);278 279 memcpy(to, from, copy * sizeof(long));280 if (count % BITS_PER_LONG)281 to[copy - 1] &= BITMAP_LAST_WORD_MASK(count);282 memset(to + copy, 0, bitmap_size(size) - copy * sizeof(long));283}284 285/*286 * On 32-bit systems bitmaps are represented as u32 arrays internally. On LE64287 * machines the order of hi and lo parts of numbers match the bitmap structure.288 * In both cases conversion is not needed when copying data from/to arrays of289 * u32. But in LE64 case, typecast in bitmap_copy_clear_tail() may lead290 * to out-of-bound access. To avoid that, both LE and BE variants of 64-bit291 * architectures are not using bitmap_copy_clear_tail().292 */293#if BITS_PER_LONG == 64294void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,295 unsigned int nbits);296void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,297 unsigned int nbits);298#else299#define bitmap_from_arr32(bitmap, buf, nbits) \300 bitmap_copy_clear_tail((unsigned long *) (bitmap), \301 (const unsigned long *) (buf), (nbits))302#define bitmap_to_arr32(buf, bitmap, nbits) \303 bitmap_copy_clear_tail((unsigned long *) (buf), \304 (const unsigned long *) (bitmap), (nbits))305#endif306 307/*308 * On 64-bit systems bitmaps are represented as u64 arrays internally. So,309 * the conversion is not needed when copying data from/to arrays of u64.310 */311#if BITS_PER_LONG == 32312void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits);313void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits);314#else315#define bitmap_from_arr64(bitmap, buf, nbits) \316 bitmap_copy_clear_tail((unsigned long *)(bitmap), (const unsigned long *)(buf), (nbits))317#define bitmap_to_arr64(buf, bitmap, nbits) \318 bitmap_copy_clear_tail((unsigned long *)(buf), (const unsigned long *)(bitmap), (nbits))319#endif320 321static __always_inline322bool bitmap_and(unsigned long *dst, const unsigned long *src1,323 const unsigned long *src2, unsigned int nbits)324{325 if (small_const_nbits(nbits))326 return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;327 return __bitmap_and(dst, src1, src2, nbits);328}329 330static __always_inline331void bitmap_or(unsigned long *dst, const unsigned long *src1,332 const unsigned long *src2, unsigned int nbits)333{334 if (small_const_nbits(nbits))335 *dst = *src1 | *src2;336 else337 __bitmap_or(dst, src1, src2, nbits);338}339 340static __always_inline341void bitmap_xor(unsigned long *dst, const unsigned long *src1,342 const unsigned long *src2, unsigned int nbits)343{344 if (small_const_nbits(nbits))345 *dst = *src1 ^ *src2;346 else347 __bitmap_xor(dst, src1, src2, nbits);348}349 350static __always_inline351bool bitmap_andnot(unsigned long *dst, const unsigned long *src1,352 const unsigned long *src2, unsigned int nbits)353{354 if (small_const_nbits(nbits))355 return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;356 return __bitmap_andnot(dst, src1, src2, nbits);357}358 359static __always_inline360void bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int nbits)361{362 if (small_const_nbits(nbits))363 *dst = ~(*src);364 else365 __bitmap_complement(dst, src, nbits);366}367 368#ifdef __LITTLE_ENDIAN369#define BITMAP_MEM_ALIGNMENT 8370#else371#define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))372#endif373#define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)374 375static __always_inline376bool bitmap_equal(const unsigned long *src1, const unsigned long *src2, unsigned int nbits)377{378 if (small_const_nbits(nbits))379 return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));380 if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) &&381 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))382 return !memcmp(src1, src2, nbits / 8);383 return __bitmap_equal(src1, src2, nbits);384}385 386/**387 * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third388 * @src1: Pointer to bitmap 1389 * @src2: Pointer to bitmap 2 will be or'ed with bitmap 1390 * @src3: Pointer to bitmap 3. Compare to the result of *@src1 | *@src2391 * @nbits: number of bits in each of these bitmaps392 *393 * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise394 */395static __always_inline396bool bitmap_or_equal(const unsigned long *src1, const unsigned long *src2,397 const unsigned long *src3, unsigned int nbits)398{399 if (!small_const_nbits(nbits))400 return __bitmap_or_equal(src1, src2, src3, nbits);401 402 return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));403}404 405static __always_inline406bool bitmap_intersects(const unsigned long *src1, const unsigned long *src2, unsigned int nbits)407{408 if (small_const_nbits(nbits))409 return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;410 else411 return __bitmap_intersects(src1, src2, nbits);412}413 414static __always_inline415bool bitmap_subset(const unsigned long *src1, const unsigned long *src2, unsigned int nbits)416{417 if (small_const_nbits(nbits))418 return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));419 else420 return __bitmap_subset(src1, src2, nbits);421}422 423static __always_inline424bool bitmap_empty(const unsigned long *src, unsigned nbits)425{426 if (small_const_nbits(nbits))427 return ! (*src & BITMAP_LAST_WORD_MASK(nbits));428 429 return find_first_bit(src, nbits) == nbits;430}431 432static __always_inline433bool bitmap_full(const unsigned long *src, unsigned int nbits)434{435 if (small_const_nbits(nbits))436 return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));437 438 return find_first_zero_bit(src, nbits) == nbits;439}440 441static __always_inline442unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits)443{444 if (small_const_nbits(nbits))445 return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));446 return __bitmap_weight(src, nbits);447}448 449static __always_inline450unsigned long bitmap_weight_and(const unsigned long *src1,451 const unsigned long *src2, unsigned int nbits)452{453 if (small_const_nbits(nbits))454 return hweight_long(*src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits));455 return __bitmap_weight_and(src1, src2, nbits);456}457 458static __always_inline459unsigned long bitmap_weight_andnot(const unsigned long *src1,460 const unsigned long *src2, unsigned int nbits)461{462 if (small_const_nbits(nbits))463 return hweight_long(*src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits));464 return __bitmap_weight_andnot(src1, src2, nbits);465}466 467static __always_inline468void bitmap_set(unsigned long *map, unsigned int start, unsigned int nbits)469{470 if (__builtin_constant_p(nbits) && nbits == 1)471 __set_bit(start, map);472 else if (small_const_nbits(start + nbits))473 *map |= GENMASK(start + nbits - 1, start);474 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&475 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&476 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&477 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))478 memset((char *)map + start / 8, 0xff, nbits / 8);479 else480 __bitmap_set(map, start, nbits);481}482 483static __always_inline484void bitmap_clear(unsigned long *map, unsigned int start, unsigned int nbits)485{486 if (__builtin_constant_p(nbits) && nbits == 1)487 __clear_bit(start, map);488 else if (small_const_nbits(start + nbits))489 *map &= ~GENMASK(start + nbits - 1, start);490 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&491 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&492 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&493 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))494 memset((char *)map + start / 8, 0, nbits / 8);495 else496 __bitmap_clear(map, start, nbits);497}498 499static __always_inline500void bitmap_shift_right(unsigned long *dst, const unsigned long *src,501 unsigned int shift, unsigned int nbits)502{503 if (small_const_nbits(nbits))504 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;505 else506 __bitmap_shift_right(dst, src, shift, nbits);507}508 509static __always_inline510void bitmap_shift_left(unsigned long *dst, const unsigned long *src,511 unsigned int shift, unsigned int nbits)512{513 if (small_const_nbits(nbits))514 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits);515 else516 __bitmap_shift_left(dst, src, shift, nbits);517}518 519static __always_inline520void bitmap_replace(unsigned long *dst,521 const unsigned long *old,522 const unsigned long *new,523 const unsigned long *mask,524 unsigned int nbits)525{526 if (small_const_nbits(nbits))527 *dst = (*old & ~(*mask)) | (*new & *mask);528 else529 __bitmap_replace(dst, old, new, mask, nbits);530}531 532/**533 * bitmap_scatter - Scatter a bitmap according to the given mask534 * @dst: scattered bitmap535 * @src: gathered bitmap536 * @mask: mask representing bits to assign to in the scattered bitmap537 * @nbits: number of bits in each of these bitmaps538 *539 * Scatters bitmap with sequential bits according to the given @mask.540 *541 * Example:542 * If @src bitmap = 0x005a, with @mask = 0x1313, @dst will be 0x0302.543 *544 * Or in binary form545 * @src @mask @dst546 * 0000000001011010 0001001100010011 0000001100000010547 *548 * (Bits 0, 1, 2, 3, 4, 5 are copied to the bits 0, 1, 4, 8, 9, 12)549 *550 * A more 'visual' description of the operation::551 *552 * src: 0000000001011010553 * ||||||554 * +------+|||||555 * | +----+||||556 * | |+----+|||557 * | || +-+||558 * | || | ||559 * mask: ...v..vv...v..vv560 * ...0..11...0..10561 * dst: 0000001100000010562 *563 * A relationship exists between bitmap_scatter() and bitmap_gather().564 * bitmap_gather() can be seen as the 'reverse' bitmap_scatter() operation.565 * See bitmap_scatter() for details related to this relationship.566 */567static __always_inline568void bitmap_scatter(unsigned long *dst, const unsigned long *src,569 const unsigned long *mask, unsigned int nbits)570{571 unsigned int n = 0;572 unsigned int bit;573 574 bitmap_zero(dst, nbits);575 576 for_each_set_bit(bit, mask, nbits)577 __assign_bit(bit, dst, test_bit(n++, src));578}579 580/**581 * bitmap_gather - Gather a bitmap according to given mask582 * @dst: gathered bitmap583 * @src: scattered bitmap584 * @mask: mask representing bits to extract from in the scattered bitmap585 * @nbits: number of bits in each of these bitmaps586 *587 * Gathers bitmap with sparse bits according to the given @mask.588 *589 * Example:590 * If @src bitmap = 0x0302, with @mask = 0x1313, @dst will be 0x001a.591 *592 * Or in binary form593 * @src @mask @dst594 * 0000001100000010 0001001100010011 0000000000011010595 *596 * (Bits 0, 1, 4, 8, 9, 12 are copied to the bits 0, 1, 2, 3, 4, 5)597 *598 * A more 'visual' description of the operation::599 *600 * mask: ...v..vv...v..vv601 * src: 0000001100000010602 * ^ ^^ ^ 0603 * | || | 10604 * | || > 010605 * | |+--> 1010606 * | +--> 11010607 * +----> 011010608 * dst: 0000000000011010609 *610 * A relationship exists between bitmap_gather() and bitmap_scatter(). See611 * bitmap_scatter() for the bitmap scatter detailed operations.612 * Suppose scattered computed using bitmap_scatter(scattered, src, mask, n).613 * The operation bitmap_gather(result, scattered, mask, n) leads to a result614 * equal or equivalent to src.615 *616 * The result can be 'equivalent' because bitmap_scatter() and bitmap_gather()617 * are not bijective.618 * The result and src values are equivalent in that sense that a call to619 * bitmap_scatter(res, src, mask, n) and a call to620 * bitmap_scatter(res, result, mask, n) will lead to the same res value.621 */622static __always_inline623void bitmap_gather(unsigned long *dst, const unsigned long *src,624 const unsigned long *mask, unsigned int nbits)625{626 unsigned int n = 0;627 unsigned int bit;628 629 bitmap_zero(dst, nbits);630 631 for_each_set_bit(bit, mask, nbits)632 __assign_bit(n++, dst, test_bit(bit, src));633}634 635static __always_inline636void bitmap_next_set_region(unsigned long *bitmap, unsigned int *rs,637 unsigned int *re, unsigned int end)638{639 *rs = find_next_bit(bitmap, end, *rs);640 *re = find_next_zero_bit(bitmap, end, *rs + 1);641}642 643/**644 * bitmap_release_region - release allocated bitmap region645 * @bitmap: array of unsigned longs corresponding to the bitmap646 * @pos: beginning of bit region to release647 * @order: region size (log base 2 of number of bits) to release648 *649 * This is the complement to __bitmap_find_free_region() and releases650 * the found region (by clearing it in the bitmap).651 */652static __always_inline653void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)654{655 bitmap_clear(bitmap, pos, BIT(order));656}657 658/**659 * bitmap_allocate_region - allocate bitmap region660 * @bitmap: array of unsigned longs corresponding to the bitmap661 * @pos: beginning of bit region to allocate662 * @order: region size (log base 2 of number of bits) to allocate663 *664 * Allocate (set bits in) a specified region of a bitmap.665 *666 * Returns: 0 on success, or %-EBUSY if specified region wasn't667 * free (not all bits were zero).668 */669static __always_inline670int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)671{672 unsigned int len = BIT(order);673 674 if (find_next_bit(bitmap, pos + len, pos) < pos + len)675 return -EBUSY;676 bitmap_set(bitmap, pos, len);677 return 0;678}679 680/**681 * bitmap_find_free_region - find a contiguous aligned mem region682 * @bitmap: array of unsigned longs corresponding to the bitmap683 * @bits: number of bits in the bitmap684 * @order: region size (log base 2 of number of bits) to find685 *686 * Find a region of free (zero) bits in a @bitmap of @bits bits and687 * allocate them (set them to one). Only consider regions of length688 * a power (@order) of two, aligned to that power of two, which689 * makes the search algorithm much faster.690 *691 * Returns: the bit offset in bitmap of the allocated region,692 * or -errno on failure.693 */694static __always_inline695int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)696{697 unsigned int pos, end; /* scans bitmap by regions of size order */698 699 for (pos = 0; (end = pos + BIT(order)) <= bits; pos = end) {700 if (!bitmap_allocate_region(bitmap, pos, order))701 return pos;702 }703 return -ENOMEM;704}705 706/**707 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.708 * @n: u64 value709 *710 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit711 * integers in 32-bit environment, and 64-bit integers in 64-bit one.712 *713 * There are four combinations of endianness and length of the word in linux714 * ABIs: LE64, BE64, LE32 and BE32.715 *716 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in717 * bitmaps and therefore don't require any special handling.718 *719 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory720 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the721 * other hand is represented as an array of 32-bit words and the position of722 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that723 * word. For example, bit #42 is located at 10th position of 2nd word.724 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit725 * values in memory as it usually does. But for BE we need to swap hi and lo726 * words manually.727 *728 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and729 * lo parts of u64. For LE32 it does nothing, and for BE environment it swaps730 * hi and lo words, as is expected by bitmap.731 */732#if __BITS_PER_LONG == 64733#define BITMAP_FROM_U64(n) (n)734#else735#define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \736 ((unsigned long) ((u64)(n) >> 32))737#endif738 739/**740 * bitmap_from_u64 - Check and swap words within u64.741 * @mask: source bitmap742 * @dst: destination bitmap743 *744 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``745 * to read u64 mask, we will get the wrong word.746 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,747 * but we expect the lower 32-bits of u64.748 */749static __always_inline void bitmap_from_u64(unsigned long *dst, u64 mask)750{751 bitmap_from_arr64(dst, &mask, 64);752}753 754/**755 * bitmap_read - read a value of n-bits from the memory region756 * @map: address to the bitmap memory region757 * @start: bit offset of the n-bit value758 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG759 *760 * Returns: value of @nbits bits located at the @start bit offset within the761 * @map memory region. For @nbits = 0 and @nbits > BITS_PER_LONG the return762 * value is undefined.763 */764static __always_inline765unsigned long bitmap_read(const unsigned long *map, unsigned long start, unsigned long nbits)766{767 size_t index = BIT_WORD(start);768 unsigned long offset = start % BITS_PER_LONG;769 unsigned long space = BITS_PER_LONG - offset;770 unsigned long value_low, value_high;771 772 if (unlikely(!nbits || nbits > BITS_PER_LONG))773 return 0;774 775 if (space >= nbits)776 return (map[index] >> offset) & BITMAP_LAST_WORD_MASK(nbits);777 778 value_low = map[index] & BITMAP_FIRST_WORD_MASK(start);779 value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits);780 return (value_low >> offset) | (value_high << space);781}782 783/**784 * bitmap_write - write n-bit value within a memory region785 * @map: address to the bitmap memory region786 * @value: value to write, clamped to nbits787 * @start: bit offset of the n-bit value788 * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG.789 *790 * bitmap_write() behaves as-if implemented as @nbits calls of __assign_bit(),791 * i.e. bits beyond @nbits are ignored:792 *793 * for (bit = 0; bit < nbits; bit++)794 * __assign_bit(start + bit, bitmap, val & BIT(bit));795 *796 * For @nbits == 0 and @nbits > BITS_PER_LONG no writes are performed.797 */798static __always_inline799void bitmap_write(unsigned long *map, unsigned long value,800 unsigned long start, unsigned long nbits)801{802 size_t index;803 unsigned long offset;804 unsigned long space;805 unsigned long mask;806 bool fit;807 808 if (unlikely(!nbits || nbits > BITS_PER_LONG))809 return;810 811 mask = BITMAP_LAST_WORD_MASK(nbits);812 value &= mask;813 offset = start % BITS_PER_LONG;814 space = BITS_PER_LONG - offset;815 fit = space >= nbits;816 index = BIT_WORD(start);817 818 map[index] &= (fit ? (~(mask << offset)) : ~BITMAP_FIRST_WORD_MASK(start));819 map[index] |= value << offset;820 if (fit)821 return;822 823 map[index + 1] &= BITMAP_FIRST_WORD_MASK(start + nbits);824 map[index + 1] |= (value >> space);825}826 827#define bitmap_get_value8(map, start) \828 bitmap_read(map, start, BITS_PER_BYTE)829#define bitmap_set_value8(map, value, start) \830 bitmap_write(map, value, start, BITS_PER_BYTE)831 832#endif /* __ASSEMBLY__ */833 834#endif /* __LINUX_BITMAP_H */835