596 строки
16 KiB
C
596 строки
16 KiB
C
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/*
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* lib/bitmap.c
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* Helper functions for bitmap.h.
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/module.h>
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#include <linux/ctype.h>
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#include <linux/errno.h>
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#include <linux/bitmap.h>
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#include <linux/bitops.h>
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#include <asm/uaccess.h>
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/*
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* bitmaps provide an array of bits, implemented using an an
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* array of unsigned longs. The number of valid bits in a
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* given bitmap does _not_ need to be an exact multiple of
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* BITS_PER_LONG.
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*
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* The possible unused bits in the last, partially used word
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* of a bitmap are 'don't care'. The implementation makes
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* no particular effort to keep them zero. It ensures that
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* their value will not affect the results of any operation.
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* The bitmap operations that return Boolean (bitmap_empty,
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* for example) or scalar (bitmap_weight, for example) results
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* carefully filter out these unused bits from impacting their
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* results.
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*
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* These operations actually hold to a slightly stronger rule:
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* if you don't input any bitmaps to these ops that have some
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* unused bits set, then they won't output any set unused bits
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* in output bitmaps.
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*
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* The byte ordering of bitmaps is more natural on little
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* endian architectures. See the big-endian headers
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* include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
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* for the best explanations of this ordering.
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*/
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int __bitmap_empty(const unsigned long *bitmap, int bits)
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{
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int k, lim = bits/BITS_PER_LONG;
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for (k = 0; k < lim; ++k)
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if (bitmap[k])
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return 0;
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if (bits % BITS_PER_LONG)
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if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
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return 0;
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return 1;
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}
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EXPORT_SYMBOL(__bitmap_empty);
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int __bitmap_full(const unsigned long *bitmap, int bits)
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{
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int k, lim = bits/BITS_PER_LONG;
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for (k = 0; k < lim; ++k)
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if (~bitmap[k])
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return 0;
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if (bits % BITS_PER_LONG)
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if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
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return 0;
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return 1;
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}
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EXPORT_SYMBOL(__bitmap_full);
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int __bitmap_equal(const unsigned long *bitmap1,
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const unsigned long *bitmap2, int bits)
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{
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int k, lim = bits/BITS_PER_LONG;
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for (k = 0; k < lim; ++k)
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if (bitmap1[k] != bitmap2[k])
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return 0;
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if (bits % BITS_PER_LONG)
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if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
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return 0;
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return 1;
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}
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EXPORT_SYMBOL(__bitmap_equal);
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void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
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{
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int k, lim = bits/BITS_PER_LONG;
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for (k = 0; k < lim; ++k)
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dst[k] = ~src[k];
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if (bits % BITS_PER_LONG)
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dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
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}
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EXPORT_SYMBOL(__bitmap_complement);
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/*
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* __bitmap_shift_right - logical right shift of the bits in a bitmap
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* @dst - destination bitmap
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* @src - source bitmap
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* @nbits - shift by this many bits
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* @bits - bitmap size, in bits
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*
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* Shifting right (dividing) means moving bits in the MS -> LS bit
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* direction. Zeros are fed into the vacated MS positions and the
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* LS bits shifted off the bottom are lost.
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*/
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void __bitmap_shift_right(unsigned long *dst,
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const unsigned long *src, int shift, int bits)
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{
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int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
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int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
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unsigned long mask = (1UL << left) - 1;
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for (k = 0; off + k < lim; ++k) {
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unsigned long upper, lower;
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/*
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* If shift is not word aligned, take lower rem bits of
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* word above and make them the top rem bits of result.
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*/
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if (!rem || off + k + 1 >= lim)
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upper = 0;
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else {
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upper = src[off + k + 1];
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if (off + k + 1 == lim - 1 && left)
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upper &= mask;
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}
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lower = src[off + k];
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if (left && off + k == lim - 1)
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lower &= mask;
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dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
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if (left && k == lim - 1)
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dst[k] &= mask;
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}
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if (off)
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memset(&dst[lim - off], 0, off*sizeof(unsigned long));
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}
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EXPORT_SYMBOL(__bitmap_shift_right);
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/*
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* __bitmap_shift_left - logical left shift of the bits in a bitmap
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* @dst - destination bitmap
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* @src - source bitmap
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* @nbits - shift by this many bits
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* @bits - bitmap size, in bits
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*
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* Shifting left (multiplying) means moving bits in the LS -> MS
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* direction. Zeros are fed into the vacated LS bit positions
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* and those MS bits shifted off the top are lost.
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*/
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void __bitmap_shift_left(unsigned long *dst,
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const unsigned long *src, int shift, int bits)
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{
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int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
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int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
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for (k = lim - off - 1; k >= 0; --k) {
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unsigned long upper, lower;
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/*
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* If shift is not word aligned, take upper rem bits of
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* word below and make them the bottom rem bits of result.
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*/
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if (rem && k > 0)
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lower = src[k - 1];
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else
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lower = 0;
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upper = src[k];
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if (left && k == lim - 1)
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upper &= (1UL << left) - 1;
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dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
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if (left && k + off == lim - 1)
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dst[k + off] &= (1UL << left) - 1;
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}
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if (off)
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memset(dst, 0, off*sizeof(unsigned long));
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}
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EXPORT_SYMBOL(__bitmap_shift_left);
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void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, int bits)
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{
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int k;
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int nr = BITS_TO_LONGS(bits);
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for (k = 0; k < nr; k++)
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dst[k] = bitmap1[k] & bitmap2[k];
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}
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EXPORT_SYMBOL(__bitmap_and);
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void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, int bits)
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{
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int k;
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int nr = BITS_TO_LONGS(bits);
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for (k = 0; k < nr; k++)
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dst[k] = bitmap1[k] | bitmap2[k];
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}
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EXPORT_SYMBOL(__bitmap_or);
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void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, int bits)
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{
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int k;
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int nr = BITS_TO_LONGS(bits);
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for (k = 0; k < nr; k++)
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dst[k] = bitmap1[k] ^ bitmap2[k];
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}
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EXPORT_SYMBOL(__bitmap_xor);
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void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, int bits)
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{
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int k;
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int nr = BITS_TO_LONGS(bits);
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for (k = 0; k < nr; k++)
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dst[k] = bitmap1[k] & ~bitmap2[k];
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}
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EXPORT_SYMBOL(__bitmap_andnot);
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int __bitmap_intersects(const unsigned long *bitmap1,
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const unsigned long *bitmap2, int bits)
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{
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int k, lim = bits/BITS_PER_LONG;
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for (k = 0; k < lim; ++k)
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if (bitmap1[k] & bitmap2[k])
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return 1;
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if (bits % BITS_PER_LONG)
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if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
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return 1;
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return 0;
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}
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EXPORT_SYMBOL(__bitmap_intersects);
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int __bitmap_subset(const unsigned long *bitmap1,
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const unsigned long *bitmap2, int bits)
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{
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int k, lim = bits/BITS_PER_LONG;
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for (k = 0; k < lim; ++k)
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if (bitmap1[k] & ~bitmap2[k])
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return 0;
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if (bits % BITS_PER_LONG)
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if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
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return 0;
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return 1;
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}
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EXPORT_SYMBOL(__bitmap_subset);
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#if BITS_PER_LONG == 32
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int __bitmap_weight(const unsigned long *bitmap, int bits)
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{
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int k, w = 0, lim = bits/BITS_PER_LONG;
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for (k = 0; k < lim; k++)
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w += hweight32(bitmap[k]);
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if (bits % BITS_PER_LONG)
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w += hweight32(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
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return w;
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}
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#else
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int __bitmap_weight(const unsigned long *bitmap, int bits)
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{
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int k, w = 0, lim = bits/BITS_PER_LONG;
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for (k = 0; k < lim; k++)
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w += hweight64(bitmap[k]);
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if (bits % BITS_PER_LONG)
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w += hweight64(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
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return w;
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}
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#endif
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EXPORT_SYMBOL(__bitmap_weight);
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/*
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* Bitmap printing & parsing functions: first version by Bill Irwin,
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* second version by Paul Jackson, third by Joe Korty.
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*/
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#define CHUNKSZ 32
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#define nbits_to_hold_value(val) fls(val)
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#define roundup_power2(val,modulus) (((val) + (modulus) - 1) & ~((modulus) - 1))
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#define unhex(c) (isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10))
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#define BASEDEC 10 /* fancier cpuset lists input in decimal */
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/**
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* bitmap_scnprintf - convert bitmap to an ASCII hex string.
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* @buf: byte buffer into which string is placed
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* @buflen: reserved size of @buf, in bytes
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* @maskp: pointer to bitmap to convert
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* @nmaskbits: size of bitmap, in bits
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*
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* Exactly @nmaskbits bits are displayed. Hex digits are grouped into
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* comma-separated sets of eight digits per set.
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*/
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int bitmap_scnprintf(char *buf, unsigned int buflen,
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const unsigned long *maskp, int nmaskbits)
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{
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int i, word, bit, len = 0;
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unsigned long val;
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const char *sep = "";
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int chunksz;
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u32 chunkmask;
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chunksz = nmaskbits & (CHUNKSZ - 1);
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if (chunksz == 0)
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chunksz = CHUNKSZ;
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i = roundup_power2(nmaskbits, CHUNKSZ) - CHUNKSZ;
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for (; i >= 0; i -= CHUNKSZ) {
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chunkmask = ((1ULL << chunksz) - 1);
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word = i / BITS_PER_LONG;
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bit = i % BITS_PER_LONG;
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val = (maskp[word] >> bit) & chunkmask;
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len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
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(chunksz+3)/4, val);
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chunksz = CHUNKSZ;
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sep = ",";
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}
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return len;
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}
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EXPORT_SYMBOL(bitmap_scnprintf);
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/**
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* bitmap_parse - convert an ASCII hex string into a bitmap.
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* @buf: pointer to buffer in user space containing string.
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* @buflen: buffer size in bytes. If string is smaller than this
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* then it must be terminated with a \0.
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* @maskp: pointer to bitmap array that will contain result.
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* @nmaskbits: size of bitmap, in bits.
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*
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* Commas group hex digits into chunks. Each chunk defines exactly 32
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* bits of the resultant bitmask. No chunk may specify a value larger
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* than 32 bits (-EOVERFLOW), and if a chunk specifies a smaller value
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* then leading 0-bits are prepended. -EINVAL is returned for illegal
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* characters and for grouping errors such as "1,,5", ",44", "," and "".
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* Leading and trailing whitespace accepted, but not embedded whitespace.
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*/
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int bitmap_parse(const char __user *ubuf, unsigned int ubuflen,
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unsigned long *maskp, int nmaskbits)
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{
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int c, old_c, totaldigits, ndigits, nchunks, nbits;
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u32 chunk;
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bitmap_zero(maskp, nmaskbits);
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nchunks = nbits = totaldigits = c = 0;
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do {
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chunk = ndigits = 0;
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/* Get the next chunk of the bitmap */
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while (ubuflen) {
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old_c = c;
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if (get_user(c, ubuf++))
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return -EFAULT;
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ubuflen--;
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||
|
|
if (isspace(c))
|
||
|
|
continue;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If the last character was a space and the current
|
||
|
|
* character isn't '\0', we've got embedded whitespace.
|
||
|
|
* This is a no-no, so throw an error.
|
||
|
|
*/
|
||
|
|
if (totaldigits && c && isspace(old_c))
|
||
|
|
return -EINVAL;
|
||
|
|
|
||
|
|
/* A '\0' or a ',' signal the end of the chunk */
|
||
|
|
if (c == '\0' || c == ',')
|
||
|
|
break;
|
||
|
|
|
||
|
|
if (!isxdigit(c))
|
||
|
|
return -EINVAL;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Make sure there are at least 4 free bits in 'chunk'.
|
||
|
|
* If not, this hexdigit will overflow 'chunk', so
|
||
|
|
* throw an error.
|
||
|
|
*/
|
||
|
|
if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
|
||
|
|
return -EOVERFLOW;
|
||
|
|
|
||
|
|
chunk = (chunk << 4) | unhex(c);
|
||
|
|
ndigits++; totaldigits++;
|
||
|
|
}
|
||
|
|
if (ndigits == 0)
|
||
|
|
return -EINVAL;
|
||
|
|
if (nchunks == 0 && chunk == 0)
|
||
|
|
continue;
|
||
|
|
|
||
|
|
__bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
|
||
|
|
*maskp |= chunk;
|
||
|
|
nchunks++;
|
||
|
|
nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
|
||
|
|
if (nbits > nmaskbits)
|
||
|
|
return -EOVERFLOW;
|
||
|
|
} while (ubuflen && c == ',');
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(bitmap_parse);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* bscnl_emit(buf, buflen, rbot, rtop, bp)
|
||
|
|
*
|
||
|
|
* Helper routine for bitmap_scnlistprintf(). Write decimal number
|
||
|
|
* or range to buf, suppressing output past buf+buflen, with optional
|
||
|
|
* comma-prefix. Return len of what would be written to buf, if it
|
||
|
|
* all fit.
|
||
|
|
*/
|
||
|
|
static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
|
||
|
|
{
|
||
|
|
if (len > 0)
|
||
|
|
len += scnprintf(buf + len, buflen - len, ",");
|
||
|
|
if (rbot == rtop)
|
||
|
|
len += scnprintf(buf + len, buflen - len, "%d", rbot);
|
||
|
|
else
|
||
|
|
len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
|
||
|
|
return len;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* bitmap_scnlistprintf - convert bitmap to list format ASCII string
|
||
|
|
* @buf: byte buffer into which string is placed
|
||
|
|
* @buflen: reserved size of @buf, in bytes
|
||
|
|
* @maskp: pointer to bitmap to convert
|
||
|
|
* @nmaskbits: size of bitmap, in bits
|
||
|
|
*
|
||
|
|
* Output format is a comma-separated list of decimal numbers and
|
||
|
|
* ranges. Consecutively set bits are shown as two hyphen-separated
|
||
|
|
* decimal numbers, the smallest and largest bit numbers set in
|
||
|
|
* the range. Output format is compatible with the format
|
||
|
|
* accepted as input by bitmap_parselist().
|
||
|
|
*
|
||
|
|
* The return value is the number of characters which would be
|
||
|
|
* generated for the given input, excluding the trailing '\0', as
|
||
|
|
* per ISO C99.
|
||
|
|
*/
|
||
|
|
int bitmap_scnlistprintf(char *buf, unsigned int buflen,
|
||
|
|
const unsigned long *maskp, int nmaskbits)
|
||
|
|
{
|
||
|
|
int len = 0;
|
||
|
|
/* current bit is 'cur', most recently seen range is [rbot, rtop] */
|
||
|
|
int cur, rbot, rtop;
|
||
|
|
|
||
|
|
rbot = cur = find_first_bit(maskp, nmaskbits);
|
||
|
|
while (cur < nmaskbits) {
|
||
|
|
rtop = cur;
|
||
|
|
cur = find_next_bit(maskp, nmaskbits, cur+1);
|
||
|
|
if (cur >= nmaskbits || cur > rtop + 1) {
|
||
|
|
len = bscnl_emit(buf, buflen, rbot, rtop, len);
|
||
|
|
rbot = cur;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return len;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(bitmap_scnlistprintf);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* bitmap_parselist - convert list format ASCII string to bitmap
|
||
|
|
* @buf: read nul-terminated user string from this buffer
|
||
|
|
* @mask: write resulting mask here
|
||
|
|
* @nmaskbits: number of bits in mask to be written
|
||
|
|
*
|
||
|
|
* Input format is a comma-separated list of decimal numbers and
|
||
|
|
* ranges. Consecutively set bits are shown as two hyphen-separated
|
||
|
|
* decimal numbers, the smallest and largest bit numbers set in
|
||
|
|
* the range.
|
||
|
|
*
|
||
|
|
* Returns 0 on success, -errno on invalid input strings:
|
||
|
|
* -EINVAL: second number in range smaller than first
|
||
|
|
* -EINVAL: invalid character in string
|
||
|
|
* -ERANGE: bit number specified too large for mask
|
||
|
|
*/
|
||
|
|
int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
|
||
|
|
{
|
||
|
|
unsigned a, b;
|
||
|
|
|
||
|
|
bitmap_zero(maskp, nmaskbits);
|
||
|
|
do {
|
||
|
|
if (!isdigit(*bp))
|
||
|
|
return -EINVAL;
|
||
|
|
b = a = simple_strtoul(bp, (char **)&bp, BASEDEC);
|
||
|
|
if (*bp == '-') {
|
||
|
|
bp++;
|
||
|
|
if (!isdigit(*bp))
|
||
|
|
return -EINVAL;
|
||
|
|
b = simple_strtoul(bp, (char **)&bp, BASEDEC);
|
||
|
|
}
|
||
|
|
if (!(a <= b))
|
||
|
|
return -EINVAL;
|
||
|
|
if (b >= nmaskbits)
|
||
|
|
return -ERANGE;
|
||
|
|
while (a <= b) {
|
||
|
|
set_bit(a, maskp);
|
||
|
|
a++;
|
||
|
|
}
|
||
|
|
if (*bp == ',')
|
||
|
|
bp++;
|
||
|
|
} while (*bp != '\0' && *bp != '\n');
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(bitmap_parselist);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* bitmap_find_free_region - find a contiguous aligned mem region
|
||
|
|
* @bitmap: an array of unsigned longs corresponding to the bitmap
|
||
|
|
* @bits: number of bits in the bitmap
|
||
|
|
* @order: region size to find (size is actually 1<<order)
|
||
|
|
*
|
||
|
|
* This is used to allocate a memory region from a bitmap. The idea is
|
||
|
|
* that the region has to be 1<<order sized and 1<<order aligned (this
|
||
|
|
* makes the search algorithm much faster).
|
||
|
|
*
|
||
|
|
* The region is marked as set bits in the bitmap if a free one is
|
||
|
|
* found.
|
||
|
|
*
|
||
|
|
* Returns either beginning of region or negative error
|
||
|
|
*/
|
||
|
|
int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
|
||
|
|
{
|
||
|
|
unsigned long mask;
|
||
|
|
int pages = 1 << order;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
if(pages > BITS_PER_LONG)
|
||
|
|
return -EINVAL;
|
||
|
|
|
||
|
|
/* make a mask of the order */
|
||
|
|
mask = (1ul << (pages - 1));
|
||
|
|
mask += mask - 1;
|
||
|
|
|
||
|
|
/* run up the bitmap pages bits at a time */
|
||
|
|
for (i = 0; i < bits; i += pages) {
|
||
|
|
int index = i/BITS_PER_LONG;
|
||
|
|
int offset = i - (index * BITS_PER_LONG);
|
||
|
|
if((bitmap[index] & (mask << offset)) == 0) {
|
||
|
|
/* set region in bimap */
|
||
|
|
bitmap[index] |= (mask << offset);
|
||
|
|
return i;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return -ENOMEM;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(bitmap_find_free_region);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* bitmap_release_region - release allocated bitmap region
|
||
|
|
* @bitmap: a pointer to the bitmap
|
||
|
|
* @pos: the beginning of the region
|
||
|
|
* @order: the order of the bits to release (number is 1<<order)
|
||
|
|
*
|
||
|
|
* This is the complement to __bitmap_find_free_region and releases
|
||
|
|
* the found region (by clearing it in the bitmap).
|
||
|
|
*/
|
||
|
|
void bitmap_release_region(unsigned long *bitmap, int pos, int order)
|
||
|
|
{
|
||
|
|
int pages = 1 << order;
|
||
|
|
unsigned long mask = (1ul << (pages - 1));
|
||
|
|
int index = pos/BITS_PER_LONG;
|
||
|
|
int offset = pos - (index * BITS_PER_LONG);
|
||
|
|
mask += mask - 1;
|
||
|
|
bitmap[index] &= ~(mask << offset);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(bitmap_release_region);
|
||
|
|
|
||
|
|
int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
|
||
|
|
{
|
||
|
|
int pages = 1 << order;
|
||
|
|
unsigned long mask = (1ul << (pages - 1));
|
||
|
|
int index = pos/BITS_PER_LONG;
|
||
|
|
int offset = pos - (index * BITS_PER_LONG);
|
||
|
|
|
||
|
|
/* We don't do regions of pages > BITS_PER_LONG. The
|
||
|
|
* algorithm would be a simple look for multiple zeros in the
|
||
|
|
* array, but there's no driver today that needs this. If you
|
||
|
|
* trip this BUG(), you get to code it... */
|
||
|
|
BUG_ON(pages > BITS_PER_LONG);
|
||
|
|
mask += mask - 1;
|
||
|
|
if (bitmap[index] & (mask << offset))
|
||
|
|
return -EBUSY;
|
||
|
|
bitmap[index] |= (mask << offset);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(bitmap_allocate_region);
|