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![Randy Dunlap](/assets/img/avatar_default.png)
Fix kernel-doc warnings in 2.6.20-git15 (lib/, mm/, kernel/, include/). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
836 lines
24 KiB
C
836 lines
24 KiB
C
/*
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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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* @shift : 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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* @shift : 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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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 += hweight_long(bitmap[k]);
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if (bits % BITS_PER_LONG)
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w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
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return w;
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}
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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 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 = ALIGN(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 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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* @is_user: location of buffer, 0 indicates kernel space
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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 *buf, unsigned int buflen,
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int is_user, unsigned long *maskp,
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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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const char __user *ubuf = buf;
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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 (buflen) {
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old_c = c;
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if (is_user) {
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if (__get_user(c, ubuf++))
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return -EFAULT;
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}
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else
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c = *buf++;
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buflen--;
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if (isspace(c))
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continue;
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/*
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* If the last character was a space and the current
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* character isn't '\0', we've got embedded whitespace.
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* This is a no-no, so throw an error.
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*/
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if (totaldigits && c && isspace(old_c))
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return -EINVAL;
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/* A '\0' or a ',' signal the end of the chunk */
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if (c == '\0' || c == ',')
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break;
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if (!isxdigit(c))
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return -EINVAL;
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/*
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* Make sure there are at least 4 free bits in 'chunk'.
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* If not, this hexdigit will overflow 'chunk', so
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* throw an error.
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*/
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if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
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return -EOVERFLOW;
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chunk = (chunk << 4) | unhex(c);
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ndigits++; totaldigits++;
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}
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if (ndigits == 0)
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return -EINVAL;
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if (nchunks == 0 && chunk == 0)
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continue;
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__bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
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*maskp |= chunk;
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nchunks++;
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nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
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if (nbits > nmaskbits)
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return -EOVERFLOW;
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} while (buflen && c == ',');
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return 0;
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}
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EXPORT_SYMBOL(__bitmap_parse);
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/**
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* bitmap_parse_user()
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*
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* @ubuf: pointer to user buffer containing string.
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* @ulen: 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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* Wrapper for __bitmap_parse(), providing it with user buffer.
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*
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* We cannot have this as an inline function in bitmap.h because it needs
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* linux/uaccess.h to get the access_ok() declaration and this causes
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* cyclic dependencies.
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*/
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int bitmap_parse_user(const char __user *ubuf,
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unsigned int ulen, unsigned long *maskp,
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int nmaskbits)
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{
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if (!access_ok(VERIFY_READ, ubuf, ulen))
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return -EFAULT;
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return __bitmap_parse((const char *)ubuf, ulen, 1, maskp, nmaskbits);
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}
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EXPORT_SYMBOL(bitmap_parse_user);
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|
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/*
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* bscnl_emit(buf, buflen, rbot, rtop, bp)
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*
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* Helper routine for bitmap_scnlistprintf(). Write decimal number
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* or range to buf, suppressing output past buf+buflen, with optional
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* comma-prefix. Return len of what would be written to buf, if it
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* all fit.
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*/
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static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
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{
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if (len > 0)
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len += scnprintf(buf + len, buflen - len, ",");
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if (rbot == rtop)
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len += scnprintf(buf + len, buflen - len, "%d", rbot);
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else
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len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
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return len;
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}
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|
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/**
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* bitmap_scnlistprintf - convert bitmap to list format ASCII 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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* Output format is a comma-separated list of decimal numbers and
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* ranges. Consecutively set bits are shown as two hyphen-separated
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* decimal numbers, the smallest and largest bit numbers set in
|
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* the range. Output format is compatible with the format
|
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* accepted as input by bitmap_parselist().
|
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*
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* The return value is the number of characters which would be
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* generated for the given input, excluding the trailing '\0', as
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* per ISO C99.
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*/
|
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int bitmap_scnlistprintf(char *buf, unsigned int buflen,
|
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const unsigned long *maskp, int nmaskbits)
|
|
{
|
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int len = 0;
|
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/* current bit is 'cur', most recently seen range is [rbot, rtop] */
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int cur, rbot, rtop;
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rbot = cur = find_first_bit(maskp, nmaskbits);
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while (cur < nmaskbits) {
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rtop = cur;
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cur = find_next_bit(maskp, nmaskbits, cur+1);
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if (cur >= nmaskbits || cur > rtop + 1) {
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len = bscnl_emit(buf, buflen, rbot, rtop, len);
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rbot = cur;
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}
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}
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return len;
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}
|
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EXPORT_SYMBOL(bitmap_scnlistprintf);
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|
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/**
|
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* bitmap_parselist - convert list format ASCII string to bitmap
|
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* @bp: read nul-terminated user string from this buffer
|
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* @maskp: write resulting mask here
|
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* @nmaskbits: number of bits in mask to be written
|
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*
|
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* Input format is a comma-separated list of decimal numbers and
|
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* 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.
|
|
* Error values:
|
|
* %-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_pos_to_ord(buf, pos, bits)
|
|
* @buf: pointer to a bitmap
|
|
* @pos: a bit position in @buf (0 <= @pos < @bits)
|
|
* @bits: number of valid bit positions in @buf
|
|
*
|
|
* Map the bit at position @pos in @buf (of length @bits) to the
|
|
* ordinal of which set bit it is. If it is not set or if @pos
|
|
* is not a valid bit position, map to -1.
|
|
*
|
|
* If for example, just bits 4 through 7 are set in @buf, then @pos
|
|
* values 4 through 7 will get mapped to 0 through 3, respectively,
|
|
* and other @pos values will get mapped to 0. When @pos value 7
|
|
* gets mapped to (returns) @ord value 3 in this example, that means
|
|
* that bit 7 is the 3rd (starting with 0th) set bit in @buf.
|
|
*
|
|
* The bit positions 0 through @bits are valid positions in @buf.
|
|
*/
|
|
static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
|
|
{
|
|
int i, ord;
|
|
|
|
if (pos < 0 || pos >= bits || !test_bit(pos, buf))
|
|
return -1;
|
|
|
|
i = find_first_bit(buf, bits);
|
|
ord = 0;
|
|
while (i < pos) {
|
|
i = find_next_bit(buf, bits, i + 1);
|
|
ord++;
|
|
}
|
|
BUG_ON(i != pos);
|
|
|
|
return ord;
|
|
}
|
|
|
|
/**
|
|
* bitmap_ord_to_pos(buf, ord, bits)
|
|
* @buf: pointer to bitmap
|
|
* @ord: ordinal bit position (n-th set bit, n >= 0)
|
|
* @bits: number of valid bit positions in @buf
|
|
*
|
|
* Map the ordinal offset of bit @ord in @buf to its position in @buf.
|
|
* Value of @ord should be in range 0 <= @ord < weight(buf), else
|
|
* results are undefined.
|
|
*
|
|
* If for example, just bits 4 through 7 are set in @buf, then @ord
|
|
* values 0 through 3 will get mapped to 4 through 7, respectively,
|
|
* and all other @ord values return undefined values. When @ord value 3
|
|
* gets mapped to (returns) @pos value 7 in this example, that means
|
|
* that the 3rd set bit (starting with 0th) is at position 7 in @buf.
|
|
*
|
|
* The bit positions 0 through @bits are valid positions in @buf.
|
|
*/
|
|
static int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
|
|
{
|
|
int pos = 0;
|
|
|
|
if (ord >= 0 && ord < bits) {
|
|
int i;
|
|
|
|
for (i = find_first_bit(buf, bits);
|
|
i < bits && ord > 0;
|
|
i = find_next_bit(buf, bits, i + 1))
|
|
ord--;
|
|
if (i < bits && ord == 0)
|
|
pos = i;
|
|
}
|
|
|
|
return pos;
|
|
}
|
|
|
|
/**
|
|
* bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
|
|
* @dst: remapped result
|
|
* @src: subset to be remapped
|
|
* @old: defines domain of map
|
|
* @new: defines range of map
|
|
* @bits: number of bits in each of these bitmaps
|
|
*
|
|
* Let @old and @new define a mapping of bit positions, such that
|
|
* whatever position is held by the n-th set bit in @old is mapped
|
|
* to the n-th set bit in @new. In the more general case, allowing
|
|
* for the possibility that the weight 'w' of @new is less than the
|
|
* weight of @old, map the position of the n-th set bit in @old to
|
|
* the position of the m-th set bit in @new, where m == n % w.
|
|
*
|
|
* If either of the @old and @new bitmaps are empty, or if @src and
|
|
* @dst point to the same location, then this routine copies @src
|
|
* to @dst.
|
|
*
|
|
* The positions of unset bits in @old are mapped to themselves
|
|
* (the identify map).
|
|
*
|
|
* Apply the above specified mapping to @src, placing the result in
|
|
* @dst, clearing any bits previously set in @dst.
|
|
*
|
|
* For example, lets say that @old has bits 4 through 7 set, and
|
|
* @new has bits 12 through 15 set. This defines the mapping of bit
|
|
* position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
|
|
* bit positions unchanged. So if say @src comes into this routine
|
|
* with bits 1, 5 and 7 set, then @dst should leave with bits 1,
|
|
* 13 and 15 set.
|
|
*/
|
|
void bitmap_remap(unsigned long *dst, const unsigned long *src,
|
|
const unsigned long *old, const unsigned long *new,
|
|
int bits)
|
|
{
|
|
int oldbit, w;
|
|
|
|
if (dst == src) /* following doesn't handle inplace remaps */
|
|
return;
|
|
bitmap_zero(dst, bits);
|
|
|
|
w = bitmap_weight(new, bits);
|
|
for (oldbit = find_first_bit(src, bits);
|
|
oldbit < bits;
|
|
oldbit = find_next_bit(src, bits, oldbit + 1)) {
|
|
int n = bitmap_pos_to_ord(old, oldbit, bits);
|
|
if (n < 0 || w == 0)
|
|
set_bit(oldbit, dst); /* identity map */
|
|
else
|
|
set_bit(bitmap_ord_to_pos(new, n % w, bits), dst);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(bitmap_remap);
|
|
|
|
/**
|
|
* bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
|
|
* @oldbit: bit position to be mapped
|
|
* @old: defines domain of map
|
|
* @new: defines range of map
|
|
* @bits: number of bits in each of these bitmaps
|
|
*
|
|
* Let @old and @new define a mapping of bit positions, such that
|
|
* whatever position is held by the n-th set bit in @old is mapped
|
|
* to the n-th set bit in @new. In the more general case, allowing
|
|
* for the possibility that the weight 'w' of @new is less than the
|
|
* weight of @old, map the position of the n-th set bit in @old to
|
|
* the position of the m-th set bit in @new, where m == n % w.
|
|
*
|
|
* The positions of unset bits in @old are mapped to themselves
|
|
* (the identify map).
|
|
*
|
|
* Apply the above specified mapping to bit position @oldbit, returning
|
|
* the new bit position.
|
|
*
|
|
* For example, lets say that @old has bits 4 through 7 set, and
|
|
* @new has bits 12 through 15 set. This defines the mapping of bit
|
|
* position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
|
|
* bit positions unchanged. So if say @oldbit is 5, then this routine
|
|
* returns 13.
|
|
*/
|
|
int bitmap_bitremap(int oldbit, const unsigned long *old,
|
|
const unsigned long *new, int bits)
|
|
{
|
|
int w = bitmap_weight(new, bits);
|
|
int n = bitmap_pos_to_ord(old, oldbit, bits);
|
|
if (n < 0 || w == 0)
|
|
return oldbit;
|
|
else
|
|
return bitmap_ord_to_pos(new, n % w, bits);
|
|
}
|
|
EXPORT_SYMBOL(bitmap_bitremap);
|
|
|
|
/*
|
|
* Common code for bitmap_*_region() routines.
|
|
* bitmap: array of unsigned longs corresponding to the bitmap
|
|
* pos: the beginning of the region
|
|
* order: region size (log base 2 of number of bits)
|
|
* reg_op: operation(s) to perform on that region of bitmap
|
|
*
|
|
* Can set, verify and/or release a region of bits in a bitmap,
|
|
* depending on which combination of REG_OP_* flag bits is set.
|
|
*
|
|
* A region of a bitmap is a sequence of bits in the bitmap, of
|
|
* some size '1 << order' (a power of two), aligned to that same
|
|
* '1 << order' power of two.
|
|
*
|
|
* Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
|
|
* Returns 0 in all other cases and reg_ops.
|
|
*/
|
|
|
|
enum {
|
|
REG_OP_ISFREE, /* true if region is all zero bits */
|
|
REG_OP_ALLOC, /* set all bits in region */
|
|
REG_OP_RELEASE, /* clear all bits in region */
|
|
};
|
|
|
|
static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op)
|
|
{
|
|
int nbits_reg; /* number of bits in region */
|
|
int index; /* index first long of region in bitmap */
|
|
int offset; /* bit offset region in bitmap[index] */
|
|
int nlongs_reg; /* num longs spanned by region in bitmap */
|
|
int nbitsinlong; /* num bits of region in each spanned long */
|
|
unsigned long mask; /* bitmask for one long of region */
|
|
int i; /* scans bitmap by longs */
|
|
int ret = 0; /* return value */
|
|
|
|
/*
|
|
* Either nlongs_reg == 1 (for small orders that fit in one long)
|
|
* or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
|
|
*/
|
|
nbits_reg = 1 << order;
|
|
index = pos / BITS_PER_LONG;
|
|
offset = pos - (index * BITS_PER_LONG);
|
|
nlongs_reg = BITS_TO_LONGS(nbits_reg);
|
|
nbitsinlong = min(nbits_reg, BITS_PER_LONG);
|
|
|
|
/*
|
|
* Can't do "mask = (1UL << nbitsinlong) - 1", as that
|
|
* overflows if nbitsinlong == BITS_PER_LONG.
|
|
*/
|
|
mask = (1UL << (nbitsinlong - 1));
|
|
mask += mask - 1;
|
|
mask <<= offset;
|
|
|
|
switch (reg_op) {
|
|
case REG_OP_ISFREE:
|
|
for (i = 0; i < nlongs_reg; i++) {
|
|
if (bitmap[index + i] & mask)
|
|
goto done;
|
|
}
|
|
ret = 1; /* all bits in region free (zero) */
|
|
break;
|
|
|
|
case REG_OP_ALLOC:
|
|
for (i = 0; i < nlongs_reg; i++)
|
|
bitmap[index + i] |= mask;
|
|
break;
|
|
|
|
case REG_OP_RELEASE:
|
|
for (i = 0; i < nlongs_reg; i++)
|
|
bitmap[index + i] &= ~mask;
|
|
break;
|
|
}
|
|
done:
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* bitmap_find_free_region - find a contiguous aligned mem region
|
|
* @bitmap: array of unsigned longs corresponding to the bitmap
|
|
* @bits: number of bits in the bitmap
|
|
* @order: region size (log base 2 of number of bits) to find
|
|
*
|
|
* Find a region of free (zero) bits in a @bitmap of @bits bits and
|
|
* allocate them (set them to one). Only consider regions of length
|
|
* a power (@order) of two, aligned to that power of two, which
|
|
* makes the search algorithm much faster.
|
|
*
|
|
* Return the bit offset in bitmap of the allocated region,
|
|
* or -errno on failure.
|
|
*/
|
|
int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
|
|
{
|
|
int pos; /* scans bitmap by regions of size order */
|
|
|
|
for (pos = 0; pos < bits; pos += (1 << order))
|
|
if (__reg_op(bitmap, pos, order, REG_OP_ISFREE))
|
|
break;
|
|
if (pos == bits)
|
|
return -ENOMEM;
|
|
__reg_op(bitmap, pos, order, REG_OP_ALLOC);
|
|
return pos;
|
|
}
|
|
EXPORT_SYMBOL(bitmap_find_free_region);
|
|
|
|
/**
|
|
* bitmap_release_region - release allocated bitmap region
|
|
* @bitmap: array of unsigned longs corresponding to the bitmap
|
|
* @pos: beginning of bit region to release
|
|
* @order: region size (log base 2 of number of bits) to release
|
|
*
|
|
* This is the complement to __bitmap_find_free_region() and releases
|
|
* the found region (by clearing it in the bitmap).
|
|
*
|
|
* No return value.
|
|
*/
|
|
void bitmap_release_region(unsigned long *bitmap, int pos, int order)
|
|
{
|
|
__reg_op(bitmap, pos, order, REG_OP_RELEASE);
|
|
}
|
|
EXPORT_SYMBOL(bitmap_release_region);
|
|
|
|
/**
|
|
* bitmap_allocate_region - allocate bitmap region
|
|
* @bitmap: array of unsigned longs corresponding to the bitmap
|
|
* @pos: beginning of bit region to allocate
|
|
* @order: region size (log base 2 of number of bits) to allocate
|
|
*
|
|
* Allocate (set bits in) a specified region of a bitmap.
|
|
*
|
|
* Return 0 on success, or %-EBUSY if specified region wasn't
|
|
* free (not all bits were zero).
|
|
*/
|
|
int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
|
|
{
|
|
if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
|
|
return -EBUSY;
|
|
__reg_op(bitmap, pos, order, REG_OP_ALLOC);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(bitmap_allocate_region);
|