| 1 | |
| 2 | |
| 3 | * lib/bitmap.c
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| 4 | * Helper functions for bitmap.h.
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| 5 |
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| 6 |
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| 7 | #include <linux/bitmap.h>
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| 8 | #include <linux/bitops.h>
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| 9 | #include <linux/ctype.h>
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| 10 | #include <linux/device.h>
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| 11 | #include <linux/export.h>
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| 12 | #include <linux/slab.h>
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| 13 |
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| 14 | |
| 15 | * DOC: bitmap introduction
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| 16 | *
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| 17 | * bitmaps provide an array of bits, implemented using an
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| 18 | * array of unsigned longs. The number of valid bits in a
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| 19 | * given bitmap does _not_ need to be an exact multiple of
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| 20 | * BITS_PER_LONG.
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| 21 | *
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| 22 | * The possible unused bits in the last, partially used word
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| 23 | * of a bitmap are 'don't care'. The implementation makes
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| 24 | * no particular effort to keep them zero. It ensures that
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| 25 | * their value will not affect the results of any operation.
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| 26 | * The bitmap operations that return Boolean (bitmap_empty,
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| 27 | * for example) or scalar (bitmap_weight, for example) results
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| 28 | * carefully filter out these unused bits from impacting their
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| 29 | * results.
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| 30 | *
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| 31 | * The byte ordering of bitmaps is more natural on little
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| 32 | * endian architectures. See the big-endian headers
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| 33 | * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
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| 34 | * for the best explanations of this ordering.
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| 35 |
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| 36 |
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| 37 | bool __bitmap_equal(const unsigned long *bitmap1,
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| 38 | const unsigned long *bitmap2, unsigned int bits)
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| 39 | {
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| 40 | unsigned int k, lim = bits/BITS_PER_LONG;
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| 41 | for (k = 0; k < lim; ++k)
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| 42 | if (bitmap1[k] != bitmap2[k])
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| 43 | return false;
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| 44 |
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| 45 | if (bits % BITS_PER_LONG)
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| 46 | if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
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| 47 | return false;
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| 48 |
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| 49 | return true;
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| 50 | }
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| 51 | EXPORT_SYMBOL(__bitmap_equal);
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| 52 |
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| 53 | bool __bitmap_or_equal(const unsigned long *bitmap1,
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| 54 | const unsigned long *bitmap2,
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| 55 | const unsigned long *bitmap3,
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| 56 | unsigned int bits)
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| 57 | {
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| 58 | unsigned int k, lim = bits / BITS_PER_LONG;
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| 59 | unsigned long tmp;
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| 60 |
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| 61 | for (k = 0; k < lim; ++k) {
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| 62 | if ((bitmap1[k] | bitmap2[k]) != bitmap3[k])
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| 63 | return false;
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| 64 | }
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| 65 |
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| 66 | if (!(bits % BITS_PER_LONG))
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| 67 | return true;
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| 68 |
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| 69 | tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k];
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| 70 | return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0;
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| 71 | }
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| 72 |
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| 73 | void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
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| 74 | {
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| 75 | unsigned int k, lim = BITS_TO_LONGS(bits);
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| 76 | for (k = 0; k < lim; ++k)
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| 77 | dst[k] = ~src[k];
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| 78 | }
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| 79 | EXPORT_SYMBOL(__bitmap_complement);
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| 80 |
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| 81 | |
| 82 | * __bitmap_shift_right - logical right shift of the bits in a bitmap
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| 83 | * @dst : destination bitmap
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| 84 | * @src : source bitmap
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| 85 | * @shift : shift by this many bits
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| 86 | * @nbits : bitmap size, in bits
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| 87 | *
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| 88 | * Shifting right (dividing) means moving bits in the MS -> LS bit
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| 89 | * direction. Zeros are fed into the vacated MS positions and the
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| 90 | * LS bits shifted off the bottom are lost.
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| 91 |
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| 92 | void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
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| 93 | unsigned shift, unsigned nbits)
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| 94 | {
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| 95 | unsigned k, lim = BITS_TO_LONGS(nbits);
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| 96 | unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
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| 97 | unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
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| 98 | for (k = 0; off + k < lim; ++k) {
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| 99 | unsigned long upper, lower;
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| 100 |
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| 101 | |
| 102 | * If shift is not word aligned, take lower rem bits of
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| 103 | * word above and make them the top rem bits of result.
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| 104 |
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| 105 | if (!rem || off + k + 1 >= lim)
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| 106 | upper = 0;
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| 107 | else {
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| 108 | upper = src[off + k + 1];
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| 109 | if (off + k + 1 == lim - 1)
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| 110 | upper &= mask;
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| 111 | upper <<= (BITS_PER_LONG - rem);
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| 112 | }
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| 113 | lower = src[off + k];
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| 114 | if (off + k == lim - 1)
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| 115 | lower &= mask;
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| 116 | lower >>= rem;
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| 117 | dst[k] = lower | upper;
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| 118 | }
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| 119 | if (off)
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| 120 | memset(&dst[lim - off], 0, off*sizeof(unsigned long));
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| 121 | }
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| 122 | EXPORT_SYMBOL(__bitmap_shift_right);
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| 123 |
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| 124 |
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| 125 | |
| 126 | * __bitmap_shift_left - logical left shift of the bits in a bitmap
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| 127 | * @dst : destination bitmap
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| 128 | * @src : source bitmap
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| 129 | * @shift : shift by this many bits
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| 130 | * @nbits : bitmap size, in bits
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| 131 | *
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| 132 | * Shifting left (multiplying) means moving bits in the LS -> MS
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| 133 | * direction. Zeros are fed into the vacated LS bit positions
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| 134 | * and those MS bits shifted off the top are lost.
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| 135 |
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| 136 |
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| 137 | void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
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| 138 | unsigned int shift, unsigned int nbits)
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| 139 | {
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| 140 | int k;
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| 141 | unsigned int lim = BITS_TO_LONGS(nbits);
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| 142 | unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
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| 143 | for (k = lim - off - 1; k >= 0; --k) {
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| 144 | unsigned long upper, lower;
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| 145 |
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| 146 | |
| 147 | * If shift is not word aligned, take upper rem bits of
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| 148 | * word below and make them the bottom rem bits of result.
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| 149 |
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| 150 | if (rem && k > 0)
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| 151 | lower = src[k - 1] >> (BITS_PER_LONG - rem);
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| 152 | else
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| 153 | lower = 0;
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| 154 | upper = src[k] << rem;
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| 155 | dst[k + off] = lower | upper;
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| 156 | }
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| 157 | if (off)
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| 158 | memset(dst, 0, off*sizeof(unsigned long));
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| 159 | }
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| 160 | EXPORT_SYMBOL(__bitmap_shift_left);
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| 161 |
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| 162 | |
| 163 | * bitmap_cut() - remove bit region from bitmap and right shift remaining bits
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| 164 | * @dst: destination bitmap, might overlap with src
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| 165 | * @src: source bitmap
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| 166 | * @first: start bit of region to be removed
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| 167 | * @cut: number of bits to remove
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| 168 | * @nbits: bitmap size, in bits
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| 169 | *
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| 170 | * Set the n-th bit of @dst iff the n-th bit of @src is set and
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| 171 | * n is less than @first, or the m-th bit of @src is set for any
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| 172 | * m such that @first <= n < nbits, and m = n + @cut.
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| 173 | *
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| 174 | * In pictures, example for a big-endian 32-bit architecture:
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| 175 | *
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| 176 | * The @src bitmap is::
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| 177 | *
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| 178 | * 31 63
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| 179 | * | |
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| 180 | * 10000000 11000001 11110010 00010101 10000000 11000001 01110010 00010101
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| 181 | * | | | |
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| 182 | * 16 14 0 32
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| 183 | *
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| 184 | * if @cut is 3, and @first is 14, bits 14-16 in @src are cut and @dst is::
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| 185 | *
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| 186 | * 31 63
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| 187 | * | |
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| 188 | * 10110000 00011000 00110010 00010101 00010000 00011000 00101110 01000010
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| 189 | * | | |
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| 190 | * 14 (bit 17 0 32
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| 191 | * from @src)
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| 192 | *
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| 193 | * Note that @dst and @src might overlap partially or entirely.
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| 194 | *
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| 195 | * This is implemented in the obvious way, with a shift and carry
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| 196 | * step for each moved bit. Optimisation is left as an exercise
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| 197 | * for the compiler.
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| 198 |
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| 199 | void bitmap_cut(unsigned long *dst, const unsigned long *src,
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| 200 | unsigned int first, unsigned int cut, unsigned int nbits)
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| 201 | {
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| 202 | unsigned int len = BITS_TO_LONGS(nbits);
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| 203 | unsigned long keep = 0, carry;
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| 204 | int i;
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| 205 |
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| 206 | if (first % BITS_PER_LONG) {
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| 207 | keep = src[first / BITS_PER_LONG] &
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| 208 | (~0UL >> (BITS_PER_LONG - first % BITS_PER_LONG));
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| 209 | }
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| 210 |
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| 211 | memmove(dst, src, len * sizeof(*dst));
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| 212 |
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| 213 | while (cut--) {
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| 214 | for (i = first / BITS_PER_LONG; i < len; i++) {
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| 215 | if (i < len - 1)
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| 216 | carry = dst[i + 1] & 1UL;
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| 217 | else
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| 218 | carry = 0;
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| 219 |
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| 220 | dst[i] = (dst[i] >> 1) | (carry << (BITS_PER_LONG - 1));
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| 221 | }
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| 222 | }
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| 223 |
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| 224 | dst[first / BITS_PER_LONG] &= ~0UL << (first % BITS_PER_LONG);
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| 225 | dst[first / BITS_PER_LONG] |= keep;
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| 226 | }
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| 227 | EXPORT_SYMBOL(bitmap_cut);
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| 228 |
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| 229 | bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
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| 230 | const unsigned long *bitmap2, unsigned int bits)
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| 231 | {
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| 232 | unsigned int k;
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| 233 | unsigned int lim = bits/BITS_PER_LONG;
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| 234 | unsigned long result = 0;
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| 235 |
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| 236 | for (k = 0; k < lim; k++)
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| 237 | result |= (dst[k] = bitmap1[k] & bitmap2[k]);
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| 238 | if (bits % BITS_PER_LONG)
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| 239 | result |= (dst[k] = bitmap1[k] & bitmap2[k] &
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| 240 | BITMAP_LAST_WORD_MASK(bits));
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| 241 | return result != 0;
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| 242 | }
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| 243 | EXPORT_SYMBOL(__bitmap_and);
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| 244 |
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| 245 | void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
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| 246 | const unsigned long *bitmap2, unsigned int bits)
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| 247 | {
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| 248 | unsigned int k;
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| 249 | unsigned int nr = BITS_TO_LONGS(bits);
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| 250 |
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| 251 | for (k = 0; k < nr; k++)
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| 252 | dst[k] = bitmap1[k] | bitmap2[k];
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| 253 | }
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| 254 | EXPORT_SYMBOL(__bitmap_or);
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| 255 |
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| 256 | void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
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| 257 | const unsigned long *bitmap2, unsigned int bits)
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| 258 | {
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| 259 | unsigned int k;
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| 260 | unsigned int nr = BITS_TO_LONGS(bits);
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| 261 |
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| 262 | for (k = 0; k < nr; k++)
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| 263 | dst[k] = bitmap1[k] ^ bitmap2[k];
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| 264 | }
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| 265 | EXPORT_SYMBOL(__bitmap_xor);
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| 266 |
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| 267 | bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
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| 268 | const unsigned long *bitmap2, unsigned int bits)
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| 269 | {
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| 270 | unsigned int k;
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| 271 | unsigned int lim = bits/BITS_PER_LONG;
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| 272 | unsigned long result = 0;
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| 273 |
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| 274 | for (k = 0; k < lim; k++)
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| 275 | result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
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| 276 | if (bits % BITS_PER_LONG)
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| 277 | result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
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| 278 | BITMAP_LAST_WORD_MASK(bits));
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| 279 | return result != 0;
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| 280 | }
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| 281 | EXPORT_SYMBOL(__bitmap_andnot);
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| 282 |
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| 283 | void __bitmap_replace(unsigned long *dst,
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| 284 | const unsigned long *old, const unsigned long *new,
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| 285 | const unsigned long *mask, unsigned int nbits)
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| 286 | {
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| 287 | unsigned int k;
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| 288 | unsigned int nr = BITS_TO_LONGS(nbits);
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| 289 |
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| 290 | for (k = 0; k < nr; k++)
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| 291 | dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]);
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| 292 | }
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| 293 | EXPORT_SYMBOL(__bitmap_replace);
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| 294 |
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| 295 | bool __bitmap_intersects(const unsigned long *bitmap1,
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| 296 | const unsigned long *bitmap2, unsigned int bits)
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| 297 | {
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| 298 | unsigned int k, lim = bits/BITS_PER_LONG;
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| 299 | for (k = 0; k < lim; ++k)
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| 300 | if (bitmap1[k] & bitmap2[k])
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| 301 | return true;
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| 302 |
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| 303 | if (bits % BITS_PER_LONG)
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| 304 | if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
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| 305 | return true;
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| 306 | return false;
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| 307 | }
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| 308 | EXPORT_SYMBOL(__bitmap_intersects);
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| 309 |
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| 310 | bool __bitmap_subset(const unsigned long *bitmap1,
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| 311 | const unsigned long *bitmap2, unsigned int bits)
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| 312 | {
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| 313 | unsigned int k, lim = bits/BITS_PER_LONG;
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| 314 | for (k = 0; k < lim; ++k)
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| 315 | if (bitmap1[k] & ~bitmap2[k])
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| 316 | return false;
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| 317 |
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| 318 | if (bits % BITS_PER_LONG)
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| 319 | if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
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| 320 | return false;
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| 321 | return true;
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| 322 | }
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| 323 | EXPORT_SYMBOL(__bitmap_subset);
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| 324 |
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| 325 | #define BITMAP_WEIGHT(FETCH, bits) \
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| 326 | ({ \
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| 327 | unsigned int __bits = (bits), idx, w = 0; \
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| 328 | \
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| 329 | for (idx = 0; idx < __bits / BITS_PER_LONG; idx++) \
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| 330 | w += hweight_long(FETCH); \
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| 331 | \
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| 332 | if (__bits % BITS_PER_LONG) \
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| 333 | w += hweight_long((FETCH) & BITMAP_LAST_WORD_MASK(__bits)); \
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| 334 | \
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| 335 | w; \
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| 336 | })
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| 337 |
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| 338 | unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
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| 339 | {
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| 340 | return BITMAP_WEIGHT(bitmap[idx], bits);
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| 341 | }
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| 342 | EXPORT_SYMBOL(__bitmap_weight);
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| 343 |
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| 344 | unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
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| 345 | const unsigned long *bitmap2, unsigned int bits)
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| 346 | {
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| 347 | return BITMAP_WEIGHT(bitmap1[idx] & bitmap2[idx], bits);
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| 348 | }
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| 349 | EXPORT_SYMBOL(__bitmap_weight_and);
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| 350 |
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| 351 | void __bitmap_set(unsigned long *map, unsigned int start, int len)
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| 352 | {
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| 353 | unsigned long *p = map + BIT_WORD(start);
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| 354 | const unsigned int size = start + len;
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| 355 | int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
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| 356 | unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
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| 357 |
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| 358 | while (len - bits_to_set >= 0) {
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| 359 | *p |= mask_to_set;
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| 360 | len -= bits_to_set;
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| 361 | bits_to_set = BITS_PER_LONG;
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| 362 | mask_to_set = ~0UL;
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| 363 | p++;
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| 364 | }
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| 365 | if (len) {
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| 366 | mask_to_set &= BITMAP_LAST_WORD_MASK(size);
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| 367 | *p |= mask_to_set;
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| 368 | }
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| 369 | }
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| 370 | EXPORT_SYMBOL(__bitmap_set);
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| 371 |
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| 372 | void __bitmap_clear(unsigned long *map, unsigned int start, int len)
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| 373 | {
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| 374 | unsigned long *p = map + BIT_WORD(start);
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| 375 | const unsigned int size = start + len;
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| 376 | int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
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| 377 | unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
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| 378 |
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| 379 | while (len - bits_to_clear >= 0) {
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| 380 | *p &= ~mask_to_clear;
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| 381 | len -= bits_to_clear;
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| 382 | bits_to_clear = BITS_PER_LONG;
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| 383 | mask_to_clear = ~0UL;
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| 384 | p++;
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| 385 | }
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| 386 | if (len) {
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| 387 | mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
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| 388 | *p &= ~mask_to_clear;
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| 389 | }
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| 390 | }
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| 391 | EXPORT_SYMBOL(__bitmap_clear);
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| 392 |
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| 393 | |
| 394 | * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
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| 395 | * @map: The address to base the search on
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| 396 | * @size: The bitmap size in bits
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| 397 | * @start: The bitnumber to start searching at
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| 398 | * @nr: The number of zeroed bits we're looking for
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| 399 | * @align_mask: Alignment mask for zero area
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| 400 | * @align_offset: Alignment offset for zero area.
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| 401 | *
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| 402 | * The @align_mask should be one less than a power of 2; the effect is that
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| 403 | * the bit offset of all zero areas this function finds plus @align_offset
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| 404 | * is multiple of that power of 2.
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| 405 |
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| 406 | unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
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| 407 | unsigned long size,
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| 408 | unsigned long start,
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| 409 | unsigned int nr,
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| 410 | unsigned long align_mask,
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| 411 | unsigned long align_offset)
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| 412 | {
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| 413 | unsigned long index, end, i;
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| 414 | again:
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| 415 | index = find_next_zero_bit(map, size, start);
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| 416 |
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| 417 |
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| 418 | index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
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| 419 |
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| 420 | end = index + nr;
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| 421 | if (end > size)
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| 422 | return end;
|
| 423 | i = find_next_bit(map, end, index);
|
| 424 | if (i < end) {
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| 425 | start = i + 1;
|
| 426 | goto again;
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| 427 | }
|
| 428 | return index;
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| 429 | }
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| 430 | EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
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| 431 |
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| 432 | |
| 433 | * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
|
| 434 | * @buf: pointer to a bitmap
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| 435 | * @pos: a bit position in @buf (0 <= @pos < @nbits)
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| 436 | * @nbits: number of valid bit positions in @buf
|
| 437 | *
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| 438 | * Map the bit at position @pos in @buf (of length @nbits) to the
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| 439 | * ordinal of which set bit it is. If it is not set or if @pos
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| 440 | * is not a valid bit position, map to -1.
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| 441 | *
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| 442 | * If for example, just bits 4 through 7 are set in @buf, then @pos
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| 443 | * values 4 through 7 will get mapped to 0 through 3, respectively,
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| 444 | * and other @pos values will get mapped to -1. When @pos value 7
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| 445 | * gets mapped to (returns) @ord value 3 in this example, that means
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| 446 | * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
|
| 447 | *
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| 448 | * The bit positions 0 through @bits are valid positions in @buf.
|
| 449 |
|
| 450 | static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
|
| 451 | {
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| 452 | if (pos >= nbits || !test_bit(pos, buf))
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| 453 | return -1;
|
| 454 |
|
| 455 | return bitmap_weight(buf, pos);
|
| 456 | }
|
| 457 |
|
| 458 | |
| 459 | * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
|
| 460 | * @dst: remapped result
|
| 461 | * @src: subset to be remapped
|
| 462 | * @old: defines domain of map
|
| 463 | * @new: defines range of map
|
| 464 | * @nbits: number of bits in each of these bitmaps
|
| 465 | *
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| 466 | * Let @old and @new define a mapping of bit positions, such that
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| 467 | * whatever position is held by the n-th set bit in @old is mapped
|
| 468 | * to the n-th set bit in @new. In the more general case, allowing
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| 469 | * for the possibility that the weight 'w' of @new is less than the
|
| 470 | * weight of @old, map the position of the n-th set bit in @old to
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| 471 | * the position of the m-th set bit in @new, where m == n % w.
|
| 472 | *
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| 473 | * If either of the @old and @new bitmaps are empty, or if @src and
|
| 474 | * @dst point to the same location, then this routine copies @src
|
| 475 | * to @dst.
|
| 476 | *
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| 477 | * The positions of unset bits in @old are mapped to themselves
|
| 478 | * (the identity map).
|
| 479 | *
|
| 480 | * Apply the above specified mapping to @src, placing the result in
|
| 481 | * @dst, clearing any bits previously set in @dst.
|
| 482 | *
|
| 483 | * For example, lets say that @old has bits 4 through 7 set, and
|
| 484 | * @new has bits 12 through 15 set. This defines the mapping of bit
|
| 485 | * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
|
| 486 | * bit positions unchanged. So if say @src comes into this routine
|
| 487 | * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
|
| 488 | * 13 and 15 set.
|
| 489 |
|
| 490 | void bitmap_remap(unsigned long *dst, const unsigned long *src,
|
| 491 | const unsigned long *old, const unsigned long *new,
|
| 492 | unsigned int nbits)
|
| 493 | {
|
| 494 | unsigned int oldbit, w;
|
| 495 |
|
| 496 | if (dst == src)
|
| 497 | return;
|
| 498 | bitmap_zero(dst, nbits);
|
| 499 |
|
| 500 | w = bitmap_weight(new, nbits);
|
| 501 | for_each_set_bit(oldbit, src, nbits) {
|
| 502 | int n = bitmap_pos_to_ord(old, oldbit, nbits);
|
| 503 |
|
| 504 | if (n < 0 || w == 0)
|
| 505 | set_bit(oldbit, dst);
|
| 506 | else
|
| 507 | set_bit(find_nth_bit(new, nbits, n % w), dst);
|
| 508 | }
|
| 509 | }
|
| 510 | EXPORT_SYMBOL(bitmap_remap);
|
| 511 |
|
| 512 | |
| 513 | * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
|
| 514 | * @oldbit: bit position to be mapped
|
| 515 | * @old: defines domain of map
|
| 516 | * @new: defines range of map
|
| 517 | * @bits: number of bits in each of these bitmaps
|
| 518 | *
|
| 519 | * Let @old and @new define a mapping of bit positions, such that
|
| 520 | * whatever position is held by the n-th set bit in @old is mapped
|
| 521 | * to the n-th set bit in @new. In the more general case, allowing
|
| 522 | * for the possibility that the weight 'w' of @new is less than the
|
| 523 | * weight of @old, map the position of the n-th set bit in @old to
|
| 524 | * the position of the m-th set bit in @new, where m == n % w.
|
| 525 | *
|
| 526 | * The positions of unset bits in @old are mapped to themselves
|
| 527 | * (the identity map).
|
| 528 | *
|
| 529 | * Apply the above specified mapping to bit position @oldbit, returning
|
| 530 | * the new bit position.
|
| 531 | *
|
| 532 | * For example, lets say that @old has bits 4 through 7 set, and
|
| 533 | * @new has bits 12 through 15 set. This defines the mapping of bit
|
| 534 | * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
|
| 535 | * bit positions unchanged. So if say @oldbit is 5, then this routine
|
| 536 | * returns 13.
|
| 537 |
|
| 538 | int bitmap_bitremap(int oldbit, const unsigned long *old,
|
| 539 | const unsigned long *new, int bits)
|
| 540 | {
|
| 541 | int w = bitmap_weight(new, bits);
|
| 542 | int n = bitmap_pos_to_ord(old, oldbit, bits);
|
| 543 | if (n < 0 || w == 0)
|
| 544 | return oldbit;
|
| 545 | else
|
| 546 | return find_nth_bit(new, bits, n % w);
|
| 547 | }
|
| 548 | EXPORT_SYMBOL(bitmap_bitremap);
|
| 549 |
|
| 550 | #ifdef CONFIG_NUMA
|
| 551 | |
| 552 | * bitmap_onto - translate one bitmap relative to another
|
| 553 | * @dst: resulting translated bitmap
|
| 554 | * @orig: original untranslated bitmap
|
| 555 | * @relmap: bitmap relative to which translated
|
| 556 | * @bits: number of bits in each of these bitmaps
|
| 557 | *
|
| 558 | * Set the n-th bit of @dst iff there exists some m such that the
|
| 559 | * n-th bit of @relmap is set, the m-th bit of @orig is set, and
|
| 560 | * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
|
| 561 | * (If you understood the previous sentence the first time your
|
| 562 | * read it, you're overqualified for your current job.)
|
| 563 | *
|
| 564 | * In other words, @orig is mapped onto (surjectively) @dst,
|
| 565 | * using the map { <n, m> | the n-th bit of @relmap is the
|
| 566 | * m-th set bit of @relmap }.
|
| 567 | *
|
| 568 | * Any set bits in @orig above bit number W, where W is the
|
| 569 | * weight of (number of set bits in) @relmap are mapped nowhere.
|
| 570 | * In particular, if for all bits m set in @orig, m >= W, then
|
| 571 | * @dst will end up empty. In situations where the possibility
|
| 572 | * of such an empty result is not desired, one way to avoid it is
|
| 573 | * to use the bitmap_fold() operator, below, to first fold the
|
| 574 | * @orig bitmap over itself so that all its set bits x are in the
|
| 575 | * range 0 <= x < W. The bitmap_fold() operator does this by
|
| 576 | * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
|
| 577 | *
|
| 578 | * Example [1] for bitmap_onto():
|
| 579 | * Let's say @relmap has bits 30-39 set, and @orig has bits
|
| 580 | * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
|
| 581 | * @dst will have bits 31, 33, 35, 37 and 39 set.
|
| 582 | *
|
| 583 | * When bit 0 is set in @orig, it means turn on the bit in
|
| 584 | * @dst corresponding to whatever is the first bit (if any)
|
| 585 | * that is turned on in @relmap. Since bit 0 was off in the
|
| 586 | * above example, we leave off that bit (bit 30) in @dst.
|
| 587 | *
|
| 588 | * When bit 1 is set in @orig (as in the above example), it
|
| 589 | * means turn on the bit in @dst corresponding to whatever
|
| 590 | * is the second bit that is turned on in @relmap. The second
|
| 591 | * bit in @relmap that was turned on in the above example was
|
| 592 | * bit 31, so we turned on bit 31 in @dst.
|
| 593 | *
|
| 594 | * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
|
| 595 | * because they were the 4th, 6th, 8th and 10th set bits
|
| 596 | * set in @relmap, and the 4th, 6th, 8th and 10th bits of
|
| 597 | * @orig (i.e. bits 3, 5, 7 and 9) were also set.
|
| 598 | *
|
| 599 | * When bit 11 is set in @orig, it means turn on the bit in
|
| 600 | * @dst corresponding to whatever is the twelfth bit that is
|
| 601 | * turned on in @relmap. In the above example, there were
|
| 602 | * only ten bits turned on in @relmap (30..39), so that bit
|
| 603 | * 11 was set in @orig had no affect on @dst.
|
| 604 | *
|
| 605 | * Example [2] for bitmap_fold() + bitmap_onto():
|
| 606 | * Let's say @relmap has these ten bits set::
|
| 607 | *
|
| 608 | * 40 41 42 43 45 48 53 61 74 95
|
| 609 | *
|
| 610 | * (for the curious, that's 40 plus the first ten terms of the
|
| 611 | * Fibonacci sequence.)
|
| 612 | *
|
| 613 | * Further lets say we use the following code, invoking
|
| 614 | * bitmap_fold() then bitmap_onto, as suggested above to
|
| 615 | * avoid the possibility of an empty @dst result::
|
| 616 | *
|
| 617 | * unsigned long *tmp; // a temporary bitmap's bits
|
| 618 | *
|
| 619 | * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
|
| 620 | * bitmap_onto(dst, tmp, relmap, bits);
|
| 621 | *
|
| 622 | * Then this table shows what various values of @dst would be, for
|
| 623 | * various @orig's. I list the zero-based positions of each set bit.
|
| 624 | * The tmp column shows the intermediate result, as computed by
|
| 625 | * using bitmap_fold() to fold the @orig bitmap modulo ten
|
| 626 | * (the weight of @relmap):
|
| 627 | *
|
| 628 | * =============== ============== =================
|
| 629 | * @orig tmp @dst
|
| 630 | * 0 0 40
|
| 631 | * 1 1 41
|
| 632 | * 9 9 95
|
| 633 | * 10 0 40 [#f1]_
|
| 634 | * 1 3 5 7 1 3 5 7 41 43 48 61
|
| 635 | * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
|
| 636 | * 0 9 18 27 0 9 8 7 40 61 74 95
|
| 637 | * 0 10 20 30 0 40
|
| 638 | * 0 11 22 33 0 1 2 3 40 41 42 43
|
| 639 | * 0 12 24 36 0 2 4 6 40 42 45 53
|
| 640 | * 78 102 211 1 2 8 41 42 74 [#f1]_
|
| 641 | * =============== ============== =================
|
| 642 | *
|
| 643 | * .. [#f1]
|
| 644 | *
|
| 645 | * For these marked lines, if we hadn't first done bitmap_fold()
|
| 646 | * into tmp, then the @dst result would have been empty.
|
| 647 | *
|
| 648 | * If either of @orig or @relmap is empty (no set bits), then @dst
|
| 649 | * will be returned empty.
|
| 650 | *
|
| 651 | * If (as explained above) the only set bits in @orig are in positions
|
| 652 | * m where m >= W, (where W is the weight of @relmap) then @dst will
|
| 653 | * once again be returned empty.
|
| 654 | *
|
| 655 | * All bits in @dst not set by the above rule are cleared.
|
| 656 |
|
| 657 | void bitmap_onto(unsigned long *dst, const unsigned long *orig,
|
| 658 | const unsigned long *relmap, unsigned int bits)
|
| 659 | {
|
| 660 | unsigned int n, m;
|
| 661 |
|
| 662 | if (dst == orig)
|
| 663 | return;
|
| 664 | bitmap_zero(dst, bits);
|
| 665 |
|
| 666 | |
| 667 | * The following code is a more efficient, but less
|
| 668 | * obvious, equivalent to the loop:
|
| 669 | * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
|
| 670 | * n = find_nth_bit(orig, bits, m);
|
| 671 | * if (test_bit(m, orig))
|
| 672 | * set_bit(n, dst);
|
| 673 | * }
|
| 674 |
|
| 675 |
|
| 676 | m = 0;
|
| 677 | for_each_set_bit(n, relmap, bits) {
|
| 678 |
|
| 679 | if (test_bit(m, orig))
|
| 680 | set_bit(n, dst);
|
| 681 | m++;
|
| 682 | }
|
| 683 | }
|
| 684 |
|
| 685 | |
| 686 | * bitmap_fold - fold larger bitmap into smaller, modulo specified size
|
| 687 | * @dst: resulting smaller bitmap
|
| 688 | * @orig: original larger bitmap
|
| 689 | * @sz: specified size
|
| 690 | * @nbits: number of bits in each of these bitmaps
|
| 691 | *
|
| 692 | * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
|
| 693 | * Clear all other bits in @dst. See further the comment and
|
| 694 | * Example [2] for bitmap_onto() for why and how to use this.
|
| 695 |
|
| 696 | void bitmap_fold(unsigned long *dst, const unsigned long *orig,
|
| 697 | unsigned int sz, unsigned int nbits)
|
| 698 | {
|
| 699 | unsigned int oldbit;
|
| 700 |
|
| 701 | if (dst == orig)
|
| 702 | return;
|
| 703 | bitmap_zero(dst, nbits);
|
| 704 |
|
| 705 | for_each_set_bit(oldbit, orig, nbits)
|
| 706 | set_bit(oldbit % sz, dst);
|
| 707 | }
|
| 708 | #endif
|
| 709 |
|
| 710 | unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
|
| 711 | {
|
| 712 | return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
|
| 713 | flags);
|
| 714 | }
|
| 715 | EXPORT_SYMBOL(bitmap_alloc);
|
| 716 |
|
| 717 | unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
|
| 718 | {
|
| 719 | return bitmap_alloc(nbits, flags | __GFP_ZERO);
|
| 720 | }
|
| 721 | EXPORT_SYMBOL(bitmap_zalloc);
|
| 722 |
|
| 723 | unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node)
|
| 724 | {
|
| 725 | return kmalloc_array_node(BITS_TO_LONGS(nbits), sizeof(unsigned long),
|
| 726 | flags, node);
|
| 727 | }
|
| 728 | EXPORT_SYMBOL(bitmap_alloc_node);
|
| 729 |
|
| 730 | unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node)
|
| 731 | {
|
| 732 | return bitmap_alloc_node(nbits, flags | __GFP_ZERO, node);
|
| 733 | }
|
| 734 | EXPORT_SYMBOL(bitmap_zalloc_node);
|
| 735 |
|
| 736 | void bitmap_free(const unsigned long *bitmap)
|
| 737 | {
|
| 738 | kfree(bitmap);
|
| 739 | }
|
| 740 | EXPORT_SYMBOL(bitmap_free);
|
| 741 |
|
| 742 | static void devm_bitmap_free(void *data)
|
| 743 | {
|
| 744 | unsigned long *bitmap = data;
|
| 745 |
|
| 746 | bitmap_free(bitmap);
|
| 747 | }
|
| 748 |
|
| 749 | unsigned long *devm_bitmap_alloc(struct device *dev,
|
| 750 | unsigned int nbits, gfp_t flags)
|
| 751 | {
|
| 752 | unsigned long *bitmap;
|
| 753 | int ret;
|
| 754 |
|
| 755 | bitmap = bitmap_alloc(nbits, flags);
|
| 756 | if (!bitmap)
|
| 757 | return NULL;
|
| 758 |
|
| 759 | ret = devm_add_action_or_reset(dev, devm_bitmap_free, bitmap);
|
| 760 | if (ret)
|
| 761 | return NULL;
|
| 762 |
|
| 763 | return bitmap;
|
| 764 | }
|
| 765 | EXPORT_SYMBOL_GPL(devm_bitmap_alloc);
|
| 766 |
|
| 767 | unsigned long *devm_bitmap_zalloc(struct device *dev,
|
| 768 | unsigned int nbits, gfp_t flags)
|
| 769 | {
|
| 770 | return devm_bitmap_alloc(dev, nbits, flags | __GFP_ZERO);
|
| 771 | }
|
| 772 | EXPORT_SYMBOL_GPL(devm_bitmap_zalloc);
|
| 773 |
|
| 774 | #if BITS_PER_LONG == 64
|
| 775 | |
| 776 | * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
|
| 777 | * @bitmap: array of unsigned longs, the destination bitmap
|
| 778 | * @buf: array of u32 (in host byte order), the source bitmap
|
| 779 | * @nbits: number of bits in @bitmap
|
| 780 |
|
| 781 | void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)
|
| 782 | {
|
| 783 | unsigned int i, halfwords;
|
| 784 |
|
| 785 | halfwords = DIV_ROUND_UP(nbits, 32);
|
| 786 | for (i = 0; i < halfwords; i++) {
|
| 787 | bitmap[i/2] = (unsigned long) buf[i];
|
| 788 | if (++i < halfwords)
|
| 789 | bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
|
| 790 | }
|
| 791 |
|
| 792 |
|
| 793 | if (nbits % BITS_PER_LONG)
|
| 794 | bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
|
| 795 | }
|
| 796 | EXPORT_SYMBOL(bitmap_from_arr32);
|
| 797 |
|
| 798 | |
| 799 | * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
|
| 800 | * @buf: array of u32 (in host byte order), the dest bitmap
|
| 801 | * @bitmap: array of unsigned longs, the source bitmap
|
| 802 | * @nbits: number of bits in @bitmap
|
| 803 |
|
| 804 | void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
|
| 805 | {
|
| 806 | unsigned int i, halfwords;
|
| 807 |
|
| 808 | halfwords = DIV_ROUND_UP(nbits, 32);
|
| 809 | for (i = 0; i < halfwords; i++) {
|
| 810 | buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
|
| 811 | if (++i < halfwords)
|
| 812 | buf[i] = (u32) (bitmap[i/2] >> 32);
|
| 813 | }
|
| 814 |
|
| 815 |
|
| 816 | if (nbits % BITS_PER_LONG)
|
| 817 | buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
|
| 818 | }
|
| 819 | EXPORT_SYMBOL(bitmap_to_arr32);
|
| 820 | #endif
|
| 821 |
|
| 822 | #if BITS_PER_LONG == 32
|
| 823 | |
| 824 | * bitmap_from_arr64 - copy the contents of u64 array of bits to bitmap
|
| 825 | * @bitmap: array of unsigned longs, the destination bitmap
|
| 826 | * @buf: array of u64 (in host byte order), the source bitmap
|
| 827 | * @nbits: number of bits in @bitmap
|
| 828 |
|
| 829 | void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits)
|
| 830 | {
|
| 831 | int n;
|
| 832 |
|
| 833 | for (n = nbits; n > 0; n -= 64) {
|
| 834 | u64 val = *buf++;
|
| 835 |
|
| 836 | *bitmap++ = val;
|
| 837 | if (n > 32)
|
| 838 | *bitmap++ = val >> 32;
|
| 839 | }
|
| 840 |
|
| 841 | |
| 842 | * Clear tail bits in the last word beyond nbits.
|
| 843 | *
|
| 844 | * Negative index is OK because here we point to the word next
|
| 845 | * to the last word of the bitmap, except for nbits == 0, which
|
| 846 | * is tested implicitly.
|
| 847 |
|
| 848 | if (nbits % BITS_PER_LONG)
|
| 849 | bitmap[-1] &= BITMAP_LAST_WORD_MASK(nbits);
|
| 850 | }
|
| 851 | EXPORT_SYMBOL(bitmap_from_arr64);
|
| 852 |
|
| 853 | |
| 854 | * bitmap_to_arr64 - copy the contents of bitmap to a u64 array of bits
|
| 855 | * @buf: array of u64 (in host byte order), the dest bitmap
|
| 856 | * @bitmap: array of unsigned longs, the source bitmap
|
| 857 | * @nbits: number of bits in @bitmap
|
| 858 |
|
| 859 | void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits)
|
| 860 | {
|
| 861 | const unsigned long *end = bitmap + BITS_TO_LONGS(nbits);
|
| 862 |
|
| 863 | while (bitmap < end) {
|
| 864 | *buf = *bitmap++;
|
| 865 | if (bitmap < end)
|
| 866 | *buf |= (u64)(*bitmap++) << 32;
|
| 867 | buf++;
|
| 868 | }
|
| 869 |
|
| 870 |
|
| 871 | if (nbits % 64)
|
| 872 | buf[-1] &= GENMASK_ULL((nbits - 1) % 64, 0);
|
| 873 | }
|
| 874 | EXPORT_SYMBOL(bitmap_to_arr64);
|
| 875 | #endif
|