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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * lib/bitmap.c4 * Helper functions for bitmap.h.5 */6 7#include <linux/bitmap.h>8#include <linux/bitops.h>9#include <linux/ctype.h>10#include <linux/device.h>11#include <linux/export.h>12#include <linux/slab.h>13 14/**15 * DOC: bitmap introduction16 *17 * bitmaps provide an array of bits, implemented using an18 * array of unsigned longs. The number of valid bits in a19 * given bitmap does _not_ need to be an exact multiple of20 * BITS_PER_LONG.21 *22 * The possible unused bits in the last, partially used word23 * of a bitmap are 'don't care'. The implementation makes24 * no particular effort to keep them zero. It ensures that25 * their value will not affect the results of any operation.26 * The bitmap operations that return Boolean (bitmap_empty,27 * for example) or scalar (bitmap_weight, for example) results28 * carefully filter out these unused bits from impacting their29 * results.30 *31 * The byte ordering of bitmaps is more natural on little32 * endian architectures. See the big-endian headers33 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h34 * for the best explanations of this ordering.35 */36 37bool __bitmap_equal(const unsigned long *bitmap1,38 const unsigned long *bitmap2, unsigned int bits)39{40 unsigned int k, lim = bits/BITS_PER_LONG;41 for (k = 0; k < lim; ++k)42 if (bitmap1[k] != bitmap2[k])43 return false;44 45 if (bits % BITS_PER_LONG)46 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))47 return false;48 49 return true;50}51EXPORT_SYMBOL(__bitmap_equal);52 53bool __bitmap_or_equal(const unsigned long *bitmap1,54 const unsigned long *bitmap2,55 const unsigned long *bitmap3,56 unsigned int bits)57{58 unsigned int k, lim = bits / BITS_PER_LONG;59 unsigned long tmp;60 61 for (k = 0; k < lim; ++k) {62 if ((bitmap1[k] | bitmap2[k]) != bitmap3[k])63 return false;64 }65 66 if (!(bits % BITS_PER_LONG))67 return true;68 69 tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k];70 return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0;71}72 73void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)74{75 unsigned int k, lim = BITS_TO_LONGS(bits);76 for (k = 0; k < lim; ++k)77 dst[k] = ~src[k];78}79EXPORT_SYMBOL(__bitmap_complement);80 81/**82 * __bitmap_shift_right - logical right shift of the bits in a bitmap83 * @dst : destination bitmap84 * @src : source bitmap85 * @shift : shift by this many bits86 * @nbits : bitmap size, in bits87 *88 * Shifting right (dividing) means moving bits in the MS -> LS bit89 * direction. Zeros are fed into the vacated MS positions and the90 * LS bits shifted off the bottom are lost.91 */92void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,93 unsigned shift, unsigned nbits)94{95 unsigned k, lim = BITS_TO_LONGS(nbits);96 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;97 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);98 for (k = 0; off + k < lim; ++k) {99 unsigned long upper, lower;100 101 /*102 * If shift is not word aligned, take lower rem bits of103 * word above and make them the top rem bits of result.104 */105 if (!rem || off + k + 1 >= lim)106 upper = 0;107 else {108 upper = src[off + k + 1];109 if (off + k + 1 == lim - 1)110 upper &= mask;111 upper <<= (BITS_PER_LONG - rem);112 }113 lower = src[off + k];114 if (off + k == lim - 1)115 lower &= mask;116 lower >>= rem;117 dst[k] = lower | upper;118 }119 if (off)120 memset(&dst[lim - off], 0, off*sizeof(unsigned long));121}122EXPORT_SYMBOL(__bitmap_shift_right);123 124 125/**126 * __bitmap_shift_left - logical left shift of the bits in a bitmap127 * @dst : destination bitmap128 * @src : source bitmap129 * @shift : shift by this many bits130 * @nbits : bitmap size, in bits131 *132 * Shifting left (multiplying) means moving bits in the LS -> MS133 * direction. Zeros are fed into the vacated LS bit positions134 * and those MS bits shifted off the top are lost.135 */136 137void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,138 unsigned int shift, unsigned int nbits)139{140 int k;141 unsigned int lim = BITS_TO_LONGS(nbits);142 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;143 for (k = lim - off - 1; k >= 0; --k) {144 unsigned long upper, lower;145 146 /*147 * If shift is not word aligned, take upper rem bits of148 * word below and make them the bottom rem bits of result.149 */150 if (rem && k > 0)151 lower = src[k - 1] >> (BITS_PER_LONG - rem);152 else153 lower = 0;154 upper = src[k] << rem;155 dst[k + off] = lower | upper;156 }157 if (off)158 memset(dst, 0, off*sizeof(unsigned long));159}160EXPORT_SYMBOL(__bitmap_shift_left);161 162/**163 * bitmap_cut() - remove bit region from bitmap and right shift remaining bits164 * @dst: destination bitmap, might overlap with src165 * @src: source bitmap166 * @first: start bit of region to be removed167 * @cut: number of bits to remove168 * @nbits: bitmap size, in bits169 *170 * Set the n-th bit of @dst iff the n-th bit of @src is set and171 * n is less than @first, or the m-th bit of @src is set for any172 * m such that @first <= n < nbits, and m = n + @cut.173 *174 * In pictures, example for a big-endian 32-bit architecture:175 *176 * The @src bitmap is::177 *178 * 31 63179 * | |180 * 10000000 11000001 11110010 00010101 10000000 11000001 01110010 00010101181 * | | | |182 * 16 14 0 32183 *184 * if @cut is 3, and @first is 14, bits 14-16 in @src are cut and @dst is::185 *186 * 31 63187 * | |188 * 10110000 00011000 00110010 00010101 00010000 00011000 00101110 01000010189 * | | |190 * 14 (bit 17 0 32191 * from @src)192 *193 * Note that @dst and @src might overlap partially or entirely.194 *195 * This is implemented in the obvious way, with a shift and carry196 * step for each moved bit. Optimisation is left as an exercise197 * for the compiler.198 */199void bitmap_cut(unsigned long *dst, const unsigned long *src,200 unsigned int first, unsigned int cut, unsigned int nbits)201{202 unsigned int len = BITS_TO_LONGS(nbits);203 unsigned long keep = 0, carry;204 int i;205 206 if (first % BITS_PER_LONG) {207 keep = src[first / BITS_PER_LONG] &208 (~0UL >> (BITS_PER_LONG - first % BITS_PER_LONG));209 }210 211 memmove(dst, src, len * sizeof(*dst));212 213 while (cut--) {214 for (i = first / BITS_PER_LONG; i < len; i++) {215 if (i < len - 1)216 carry = dst[i + 1] & 1UL;217 else218 carry = 0;219 220 dst[i] = (dst[i] >> 1) | (carry << (BITS_PER_LONG - 1));221 }222 }223 224 dst[first / BITS_PER_LONG] &= ~0UL << (first % BITS_PER_LONG);225 dst[first / BITS_PER_LONG] |= keep;226}227EXPORT_SYMBOL(bitmap_cut);228 229bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,230 const unsigned long *bitmap2, unsigned int bits)231{232 unsigned int k;233 unsigned int lim = bits/BITS_PER_LONG;234 unsigned long result = 0;235 236 for (k = 0; k < lim; k++)237 result |= (dst[k] = bitmap1[k] & bitmap2[k]);238 if (bits % BITS_PER_LONG)239 result |= (dst[k] = bitmap1[k] & bitmap2[k] &240 BITMAP_LAST_WORD_MASK(bits));241 return result != 0;242}243EXPORT_SYMBOL(__bitmap_and);244 245void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,246 const unsigned long *bitmap2, unsigned int bits)247{248 unsigned int k;249 unsigned int nr = BITS_TO_LONGS(bits);250 251 for (k = 0; k < nr; k++)252 dst[k] = bitmap1[k] | bitmap2[k];253}254EXPORT_SYMBOL(__bitmap_or);255 256void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,257 const unsigned long *bitmap2, unsigned int bits)258{259 unsigned int k;260 unsigned int nr = BITS_TO_LONGS(bits);261 262 for (k = 0; k < nr; k++)263 dst[k] = bitmap1[k] ^ bitmap2[k];264}265EXPORT_SYMBOL(__bitmap_xor);266 267bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,268 const unsigned long *bitmap2, unsigned int bits)269{270 unsigned int k;271 unsigned int lim = bits/BITS_PER_LONG;272 unsigned long result = 0;273 274 for (k = 0; k < lim; k++)275 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);276 if (bits % BITS_PER_LONG)277 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &278 BITMAP_LAST_WORD_MASK(bits));279 return result != 0;280}281EXPORT_SYMBOL(__bitmap_andnot);282 283void __bitmap_replace(unsigned long *dst,284 const unsigned long *old, const unsigned long *new,285 const unsigned long *mask, unsigned int nbits)286{287 unsigned int k;288 unsigned int nr = BITS_TO_LONGS(nbits);289 290 for (k = 0; k < nr; k++)291 dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]);292}293EXPORT_SYMBOL(__bitmap_replace);294 295bool __bitmap_intersects(const unsigned long *bitmap1,296 const unsigned long *bitmap2, unsigned int bits)297{298 unsigned int k, lim = bits/BITS_PER_LONG;299 for (k = 0; k < lim; ++k)300 if (bitmap1[k] & bitmap2[k])301 return true;302 303 if (bits % BITS_PER_LONG)304 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))305 return true;306 return false;307}308EXPORT_SYMBOL(__bitmap_intersects);309 310bool __bitmap_subset(const unsigned long *bitmap1,311 const unsigned long *bitmap2, unsigned int bits)312{313 unsigned int k, lim = bits/BITS_PER_LONG;314 for (k = 0; k < lim; ++k)315 if (bitmap1[k] & ~bitmap2[k])316 return false;317 318 if (bits % BITS_PER_LONG)319 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))320 return false;321 return true;322}323EXPORT_SYMBOL(__bitmap_subset);324 325#define BITMAP_WEIGHT(FETCH, bits) \326({ \327 unsigned int __bits = (bits), idx, w = 0; \328 \329 for (idx = 0; idx < __bits / BITS_PER_LONG; idx++) \330 w += hweight_long(FETCH); \331 \332 if (__bits % BITS_PER_LONG) \333 w += hweight_long((FETCH) & BITMAP_LAST_WORD_MASK(__bits)); \334 \335 w; \336})337 338unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)339{340 return BITMAP_WEIGHT(bitmap[idx], bits);341}342EXPORT_SYMBOL(__bitmap_weight);343 344unsigned int __bitmap_weight_and(const unsigned long *bitmap1,345 const unsigned long *bitmap2, unsigned int bits)346{347 return BITMAP_WEIGHT(bitmap1[idx] & bitmap2[idx], bits);348}349EXPORT_SYMBOL(__bitmap_weight_and);350 351unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1,352 const unsigned long *bitmap2, unsigned int bits)353{354 return BITMAP_WEIGHT(bitmap1[idx] & ~bitmap2[idx], bits);355}356EXPORT_SYMBOL(__bitmap_weight_andnot);357 358void __bitmap_set(unsigned long *map, unsigned int start, int len)359{360 unsigned long *p = map + BIT_WORD(start);361 const unsigned int size = start + len;362 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);363 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);364 365 while (len - bits_to_set >= 0) {366 *p |= mask_to_set;367 len -= bits_to_set;368 bits_to_set = BITS_PER_LONG;369 mask_to_set = ~0UL;370 p++;371 }372 if (len) {373 mask_to_set &= BITMAP_LAST_WORD_MASK(size);374 *p |= mask_to_set;375 }376}377EXPORT_SYMBOL(__bitmap_set);378 379void __bitmap_clear(unsigned long *map, unsigned int start, int len)380{381 unsigned long *p = map + BIT_WORD(start);382 const unsigned int size = start + len;383 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);384 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);385 386 while (len - bits_to_clear >= 0) {387 *p &= ~mask_to_clear;388 len -= bits_to_clear;389 bits_to_clear = BITS_PER_LONG;390 mask_to_clear = ~0UL;391 p++;392 }393 if (len) {394 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);395 *p &= ~mask_to_clear;396 }397}398EXPORT_SYMBOL(__bitmap_clear);399 400/**401 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area402 * @map: The address to base the search on403 * @size: The bitmap size in bits404 * @start: The bitnumber to start searching at405 * @nr: The number of zeroed bits we're looking for406 * @align_mask: Alignment mask for zero area407 * @align_offset: Alignment offset for zero area.408 *409 * The @align_mask should be one less than a power of 2; the effect is that410 * the bit offset of all zero areas this function finds plus @align_offset411 * is multiple of that power of 2.412 */413unsigned long bitmap_find_next_zero_area_off(unsigned long *map,414 unsigned long size,415 unsigned long start,416 unsigned int nr,417 unsigned long align_mask,418 unsigned long align_offset)419{420 unsigned long index, end, i;421again:422 index = find_next_zero_bit(map, size, start);423 424 /* Align allocation */425 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;426 427 end = index + nr;428 if (end > size)429 return end;430 i = find_next_bit(map, end, index);431 if (i < end) {432 start = i + 1;433 goto again;434 }435 return index;436}437EXPORT_SYMBOL(bitmap_find_next_zero_area_off);438 439/**440 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap441 * @buf: pointer to a bitmap442 * @pos: a bit position in @buf (0 <= @pos < @nbits)443 * @nbits: number of valid bit positions in @buf444 *445 * Map the bit at position @pos in @buf (of length @nbits) to the446 * ordinal of which set bit it is. If it is not set or if @pos447 * is not a valid bit position, map to -1.448 *449 * If for example, just bits 4 through 7 are set in @buf, then @pos450 * values 4 through 7 will get mapped to 0 through 3, respectively,451 * and other @pos values will get mapped to -1. When @pos value 7452 * gets mapped to (returns) @ord value 3 in this example, that means453 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.454 *455 * The bit positions 0 through @bits are valid positions in @buf.456 */457static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)458{459 if (pos >= nbits || !test_bit(pos, buf))460 return -1;461 462 return bitmap_weight(buf, pos);463}464 465/**466 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap467 * @dst: remapped result468 * @src: subset to be remapped469 * @old: defines domain of map470 * @new: defines range of map471 * @nbits: number of bits in each of these bitmaps472 *473 * Let @old and @new define a mapping of bit positions, such that474 * whatever position is held by the n-th set bit in @old is mapped475 * to the n-th set bit in @new. In the more general case, allowing476 * for the possibility that the weight 'w' of @new is less than the477 * weight of @old, map the position of the n-th set bit in @old to478 * the position of the m-th set bit in @new, where m == n % w.479 *480 * If either of the @old and @new bitmaps are empty, or if @src and481 * @dst point to the same location, then this routine copies @src482 * to @dst.483 *484 * The positions of unset bits in @old are mapped to themselves485 * (the identity map).486 *487 * Apply the above specified mapping to @src, placing the result in488 * @dst, clearing any bits previously set in @dst.489 *490 * For example, lets say that @old has bits 4 through 7 set, and491 * @new has bits 12 through 15 set. This defines the mapping of bit492 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other493 * bit positions unchanged. So if say @src comes into this routine494 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,495 * 13 and 15 set.496 */497void bitmap_remap(unsigned long *dst, const unsigned long *src,498 const unsigned long *old, const unsigned long *new,499 unsigned int nbits)500{501 unsigned int oldbit, w;502 503 if (dst == src) /* following doesn't handle inplace remaps */504 return;505 bitmap_zero(dst, nbits);506 507 w = bitmap_weight(new, nbits);508 for_each_set_bit(oldbit, src, nbits) {509 int n = bitmap_pos_to_ord(old, oldbit, nbits);510 511 if (n < 0 || w == 0)512 set_bit(oldbit, dst); /* identity map */513 else514 set_bit(find_nth_bit(new, nbits, n % w), dst);515 }516}517EXPORT_SYMBOL(bitmap_remap);518 519/**520 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit521 * @oldbit: bit position to be mapped522 * @old: defines domain of map523 * @new: defines range of map524 * @bits: number of bits in each of these bitmaps525 *526 * Let @old and @new define a mapping of bit positions, such that527 * whatever position is held by the n-th set bit in @old is mapped528 * to the n-th set bit in @new. In the more general case, allowing529 * for the possibility that the weight 'w' of @new is less than the530 * weight of @old, map the position of the n-th set bit in @old to531 * the position of the m-th set bit in @new, where m == n % w.532 *533 * The positions of unset bits in @old are mapped to themselves534 * (the identity map).535 *536 * Apply the above specified mapping to bit position @oldbit, returning537 * the new bit position.538 *539 * For example, lets say that @old has bits 4 through 7 set, and540 * @new has bits 12 through 15 set. This defines the mapping of bit541 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other542 * bit positions unchanged. So if say @oldbit is 5, then this routine543 * returns 13.544 */545int bitmap_bitremap(int oldbit, const unsigned long *old,546 const unsigned long *new, int bits)547{548 int w = bitmap_weight(new, bits);549 int n = bitmap_pos_to_ord(old, oldbit, bits);550 if (n < 0 || w == 0)551 return oldbit;552 else553 return find_nth_bit(new, bits, n % w);554}555EXPORT_SYMBOL(bitmap_bitremap);556 557#ifdef CONFIG_NUMA558/**559 * bitmap_onto - translate one bitmap relative to another560 * @dst: resulting translated bitmap561 * @orig: original untranslated bitmap562 * @relmap: bitmap relative to which translated563 * @bits: number of bits in each of these bitmaps564 *565 * Set the n-th bit of @dst iff there exists some m such that the566 * n-th bit of @relmap is set, the m-th bit of @orig is set, and567 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.568 * (If you understood the previous sentence the first time your569 * read it, you're overqualified for your current job.)570 *571 * In other words, @orig is mapped onto (surjectively) @dst,572 * using the map { <n, m> | the n-th bit of @relmap is the573 * m-th set bit of @relmap }.574 *575 * Any set bits in @orig above bit number W, where W is the576 * weight of (number of set bits in) @relmap are mapped nowhere.577 * In particular, if for all bits m set in @orig, m >= W, then578 * @dst will end up empty. In situations where the possibility579 * of such an empty result is not desired, one way to avoid it is580 * to use the bitmap_fold() operator, below, to first fold the581 * @orig bitmap over itself so that all its set bits x are in the582 * range 0 <= x < W. The bitmap_fold() operator does this by583 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.584 *585 * Example [1] for bitmap_onto():586 * Let's say @relmap has bits 30-39 set, and @orig has bits587 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,588 * @dst will have bits 31, 33, 35, 37 and 39 set.589 *590 * When bit 0 is set in @orig, it means turn on the bit in591 * @dst corresponding to whatever is the first bit (if any)592 * that is turned on in @relmap. Since bit 0 was off in the593 * above example, we leave off that bit (bit 30) in @dst.594 *595 * When bit 1 is set in @orig (as in the above example), it596 * means turn on the bit in @dst corresponding to whatever597 * is the second bit that is turned on in @relmap. The second598 * bit in @relmap that was turned on in the above example was599 * bit 31, so we turned on bit 31 in @dst.600 *601 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,602 * because they were the 4th, 6th, 8th and 10th set bits603 * set in @relmap, and the 4th, 6th, 8th and 10th bits of604 * @orig (i.e. bits 3, 5, 7 and 9) were also set.605 *606 * When bit 11 is set in @orig, it means turn on the bit in607 * @dst corresponding to whatever is the twelfth bit that is608 * turned on in @relmap. In the above example, there were609 * only ten bits turned on in @relmap (30..39), so that bit610 * 11 was set in @orig had no affect on @dst.611 *612 * Example [2] for bitmap_fold() + bitmap_onto():613 * Let's say @relmap has these ten bits set::614 *615 * 40 41 42 43 45 48 53 61 74 95616 *617 * (for the curious, that's 40 plus the first ten terms of the618 * Fibonacci sequence.)619 *620 * Further lets say we use the following code, invoking621 * bitmap_fold() then bitmap_onto, as suggested above to622 * avoid the possibility of an empty @dst result::623 *624 * unsigned long *tmp; // a temporary bitmap's bits625 *626 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);627 * bitmap_onto(dst, tmp, relmap, bits);628 *629 * Then this table shows what various values of @dst would be, for630 * various @orig's. I list the zero-based positions of each set bit.631 * The tmp column shows the intermediate result, as computed by632 * using bitmap_fold() to fold the @orig bitmap modulo ten633 * (the weight of @relmap):634 *635 * =============== ============== =================636 * @orig tmp @dst637 * 0 0 40638 * 1 1 41639 * 9 9 95640 * 10 0 40 [#f1]_641 * 1 3 5 7 1 3 5 7 41 43 48 61642 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45643 * 0 9 18 27 0 9 8 7 40 61 74 95644 * 0 10 20 30 0 40645 * 0 11 22 33 0 1 2 3 40 41 42 43646 * 0 12 24 36 0 2 4 6 40 42 45 53647 * 78 102 211 1 2 8 41 42 74 [#f1]_648 * =============== ============== =================649 *650 * .. [#f1]651 *652 * For these marked lines, if we hadn't first done bitmap_fold()653 * into tmp, then the @dst result would have been empty.654 *655 * If either of @orig or @relmap is empty (no set bits), then @dst656 * will be returned empty.657 *658 * If (as explained above) the only set bits in @orig are in positions659 * m where m >= W, (where W is the weight of @relmap) then @dst will660 * once again be returned empty.661 *662 * All bits in @dst not set by the above rule are cleared.663 */664void bitmap_onto(unsigned long *dst, const unsigned long *orig,665 const unsigned long *relmap, unsigned int bits)666{667 unsigned int n, m; /* same meaning as in above comment */668 669 if (dst == orig) /* following doesn't handle inplace mappings */670 return;671 bitmap_zero(dst, bits);672 673 /*674 * The following code is a more efficient, but less675 * obvious, equivalent to the loop:676 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {677 * n = find_nth_bit(orig, bits, m);678 * if (test_bit(m, orig))679 * set_bit(n, dst);680 * }681 */682 683 m = 0;684 for_each_set_bit(n, relmap, bits) {685 /* m == bitmap_pos_to_ord(relmap, n, bits) */686 if (test_bit(m, orig))687 set_bit(n, dst);688 m++;689 }690}691 692/**693 * bitmap_fold - fold larger bitmap into smaller, modulo specified size694 * @dst: resulting smaller bitmap695 * @orig: original larger bitmap696 * @sz: specified size697 * @nbits: number of bits in each of these bitmaps698 *699 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.700 * Clear all other bits in @dst. See further the comment and701 * Example [2] for bitmap_onto() for why and how to use this.702 */703void bitmap_fold(unsigned long *dst, const unsigned long *orig,704 unsigned int sz, unsigned int nbits)705{706 unsigned int oldbit;707 708 if (dst == orig) /* following doesn't handle inplace mappings */709 return;710 bitmap_zero(dst, nbits);711 712 for_each_set_bit(oldbit, orig, nbits)713 set_bit(oldbit % sz, dst);714}715#endif /* CONFIG_NUMA */716 717unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)718{719 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),720 flags);721}722EXPORT_SYMBOL(bitmap_alloc);723 724unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)725{726 return bitmap_alloc(nbits, flags | __GFP_ZERO);727}728EXPORT_SYMBOL(bitmap_zalloc);729 730unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node)731{732 return kmalloc_array_node(BITS_TO_LONGS(nbits), sizeof(unsigned long),733 flags, node);734}735EXPORT_SYMBOL(bitmap_alloc_node);736 737unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node)738{739 return bitmap_alloc_node(nbits, flags | __GFP_ZERO, node);740}741EXPORT_SYMBOL(bitmap_zalloc_node);742 743void bitmap_free(const unsigned long *bitmap)744{745 kfree(bitmap);746}747EXPORT_SYMBOL(bitmap_free);748 749static void devm_bitmap_free(void *data)750{751 unsigned long *bitmap = data;752 753 bitmap_free(bitmap);754}755 756unsigned long *devm_bitmap_alloc(struct device *dev,757 unsigned int nbits, gfp_t flags)758{759 unsigned long *bitmap;760 int ret;761 762 bitmap = bitmap_alloc(nbits, flags);763 if (!bitmap)764 return NULL;765 766 ret = devm_add_action_or_reset(dev, devm_bitmap_free, bitmap);767 if (ret)768 return NULL;769 770 return bitmap;771}772EXPORT_SYMBOL_GPL(devm_bitmap_alloc);773 774unsigned long *devm_bitmap_zalloc(struct device *dev,775 unsigned int nbits, gfp_t flags)776{777 return devm_bitmap_alloc(dev, nbits, flags | __GFP_ZERO);778}779EXPORT_SYMBOL_GPL(devm_bitmap_zalloc);780 781#if BITS_PER_LONG == 64782/**783 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap784 * @bitmap: array of unsigned longs, the destination bitmap785 * @buf: array of u32 (in host byte order), the source bitmap786 * @nbits: number of bits in @bitmap787 */788void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)789{790 unsigned int i, halfwords;791 792 halfwords = DIV_ROUND_UP(nbits, 32);793 for (i = 0; i < halfwords; i++) {794 bitmap[i/2] = (unsigned long) buf[i];795 if (++i < halfwords)796 bitmap[i/2] |= ((unsigned long) buf[i]) << 32;797 }798 799 /* Clear tail bits in last word beyond nbits. */800 if (nbits % BITS_PER_LONG)801 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);802}803EXPORT_SYMBOL(bitmap_from_arr32);804 805/**806 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits807 * @buf: array of u32 (in host byte order), the dest bitmap808 * @bitmap: array of unsigned longs, the source bitmap809 * @nbits: number of bits in @bitmap810 */811void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)812{813 unsigned int i, halfwords;814 815 halfwords = DIV_ROUND_UP(nbits, 32);816 for (i = 0; i < halfwords; i++) {817 buf[i] = (u32) (bitmap[i/2] & UINT_MAX);818 if (++i < halfwords)819 buf[i] = (u32) (bitmap[i/2] >> 32);820 }821 822 /* Clear tail bits in last element of array beyond nbits. */823 if (nbits % BITS_PER_LONG)824 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));825}826EXPORT_SYMBOL(bitmap_to_arr32);827#endif828 829#if BITS_PER_LONG == 32830/**831 * bitmap_from_arr64 - copy the contents of u64 array of bits to bitmap832 * @bitmap: array of unsigned longs, the destination bitmap833 * @buf: array of u64 (in host byte order), the source bitmap834 * @nbits: number of bits in @bitmap835 */836void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits)837{838 int n;839 840 for (n = nbits; n > 0; n -= 64) {841 u64 val = *buf++;842 843 *bitmap++ = val;844 if (n > 32)845 *bitmap++ = val >> 32;846 }847 848 /*849 * Clear tail bits in the last word beyond nbits.850 *851 * Negative index is OK because here we point to the word next852 * to the last word of the bitmap, except for nbits == 0, which853 * is tested implicitly.854 */855 if (nbits % BITS_PER_LONG)856 bitmap[-1] &= BITMAP_LAST_WORD_MASK(nbits);857}858EXPORT_SYMBOL(bitmap_from_arr64);859 860/**861 * bitmap_to_arr64 - copy the contents of bitmap to a u64 array of bits862 * @buf: array of u64 (in host byte order), the dest bitmap863 * @bitmap: array of unsigned longs, the source bitmap864 * @nbits: number of bits in @bitmap865 */866void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits)867{868 const unsigned long *end = bitmap + BITS_TO_LONGS(nbits);869 870 while (bitmap < end) {871 *buf = *bitmap++;872 if (bitmap < end)873 *buf |= (u64)(*bitmap++) << 32;874 buf++;875 }876 877 /* Clear tail bits in the last element of array beyond nbits. */878 if (nbits % 64)879 buf[-1] &= GENMASK_ULL((nbits - 1) % 64, 0);880}881EXPORT_SYMBOL(bitmap_to_arr64);882#endif883