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![Matthew Wilcox](/assets/img/avatar_default.png)
We have eight users calling bitmap_clear for a single bit and seventeen calling bitmap_set for a single bit. Rather than fix all of them to call __clear_bit or __set_bit, turn bitmap_clear and bitmap_set into inline functions and make this special case efficient. Link: http://lkml.kernel.org/r/20170628153221.11322-3-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1220 lines
36 KiB
C
1220 lines
36 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/export.h>
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#include <linux/thread_info.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 <linux/bug.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/uaccess.h>
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#include <asm/page.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_equal(const unsigned long *bitmap1,
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const unsigned long *bitmap2, unsigned int bits)
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{
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unsigned 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, unsigned int bits)
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{
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unsigned 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];
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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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* @nbits : 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, const unsigned long *src,
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unsigned shift, unsigned nbits)
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{
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unsigned k, lim = BITS_TO_LONGS(nbits);
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unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
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unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
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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)
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upper &= mask;
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upper <<= (BITS_PER_LONG - rem);
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}
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lower = src[off + k];
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if (off + k == lim - 1)
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lower &= mask;
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lower >>= rem;
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dst[k] = lower | upper;
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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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* @nbits : 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, const unsigned long *src,
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unsigned int shift, unsigned int nbits)
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{
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int k;
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unsigned int lim = BITS_TO_LONGS(nbits);
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unsigned 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] >> (BITS_PER_LONG - rem);
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else
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lower = 0;
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upper = src[k] << rem;
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dst[k + off] = lower | upper;
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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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int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, unsigned int bits)
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{
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unsigned int k;
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unsigned int lim = bits/BITS_PER_LONG;
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unsigned long result = 0;
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for (k = 0; k < lim; k++)
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result |= (dst[k] = bitmap1[k] & bitmap2[k]);
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if (bits % BITS_PER_LONG)
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result |= (dst[k] = bitmap1[k] & bitmap2[k] &
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BITMAP_LAST_WORD_MASK(bits));
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return result != 0;
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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, unsigned int bits)
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{
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unsigned int k;
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unsigned 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, unsigned int bits)
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{
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unsigned int k;
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unsigned 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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int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, unsigned int bits)
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{
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unsigned int k;
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unsigned int lim = bits/BITS_PER_LONG;
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unsigned long result = 0;
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for (k = 0; k < lim; k++)
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result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
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if (bits % BITS_PER_LONG)
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result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
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BITMAP_LAST_WORD_MASK(bits));
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return result != 0;
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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, unsigned int bits)
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{
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unsigned 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, unsigned int bits)
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{
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unsigned 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, unsigned int bits)
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{
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unsigned int k, lim = bits/BITS_PER_LONG;
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int w = 0;
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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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void __bitmap_set(unsigned long *map, unsigned int start, int len)
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{
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unsigned long *p = map + BIT_WORD(start);
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const unsigned int size = start + len;
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int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
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unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
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while (len - bits_to_set >= 0) {
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*p |= mask_to_set;
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len -= bits_to_set;
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bits_to_set = BITS_PER_LONG;
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mask_to_set = ~0UL;
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p++;
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}
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if (len) {
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mask_to_set &= BITMAP_LAST_WORD_MASK(size);
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*p |= mask_to_set;
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}
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}
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EXPORT_SYMBOL(__bitmap_set);
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void __bitmap_clear(unsigned long *map, unsigned int start, int len)
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{
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unsigned long *p = map + BIT_WORD(start);
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const unsigned int size = start + len;
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int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
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unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
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while (len - bits_to_clear >= 0) {
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*p &= ~mask_to_clear;
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len -= bits_to_clear;
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bits_to_clear = BITS_PER_LONG;
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mask_to_clear = ~0UL;
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p++;
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}
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if (len) {
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mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
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*p &= ~mask_to_clear;
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}
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}
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EXPORT_SYMBOL(__bitmap_clear);
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/**
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* bitmap_find_next_zero_area_off - find a contiguous aligned zero area
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* @map: The address to base the search on
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* @size: The bitmap size in bits
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* @start: The bitnumber to start searching at
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* @nr: The number of zeroed bits we're looking for
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* @align_mask: Alignment mask for zero area
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* @align_offset: Alignment offset for zero area.
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*
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* The @align_mask should be one less than a power of 2; the effect is that
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* the bit offset of all zero areas this function finds plus @align_offset
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* is multiple of that power of 2.
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*/
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unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
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unsigned long size,
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unsigned long start,
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unsigned int nr,
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unsigned long align_mask,
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unsigned long align_offset)
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{
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unsigned long index, end, i;
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again:
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index = find_next_zero_bit(map, size, start);
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/* Align allocation */
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index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
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end = index + nr;
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if (end > size)
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return end;
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i = find_next_bit(map, end, index);
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if (i < end) {
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start = i + 1;
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goto again;
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}
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return index;
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}
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EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
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/*
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* Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
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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 BASEDEC 10 /* fancier cpuset lists input in decimal */
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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 __force *ubuf = (const char __user __force *)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 = 0;
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ndigits = totaldigits;
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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) | hex_to_bin(c);
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totaldigits++;
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}
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if (ndigits == totaldigits)
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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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/**
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* bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
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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 __force *)ubuf,
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ulen, 1, maskp, nmaskbits);
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|
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}
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EXPORT_SYMBOL(bitmap_parse_user);
|
|
|
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/**
|
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* bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
|
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* @list: indicates whether the bitmap must be list
|
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* @buf: page aligned buffer into which string is placed
|
|
* @maskp: pointer to bitmap to convert
|
|
* @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 if list is specified or hex digits grouped into comma-separated
|
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* sets of 8 digits/set. Returns the number of characters written to buf.
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*
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* It is assumed that @buf is a pointer into a PAGE_SIZE area and that
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* sufficient storage remains at @buf to accommodate the
|
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* bitmap_print_to_pagebuf() output.
|
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*/
|
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int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
|
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int nmaskbits)
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{
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ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf;
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int n = 0;
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|
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if (len > 1)
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n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
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scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
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return n;
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}
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EXPORT_SYMBOL(bitmap_print_to_pagebuf);
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|
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/**
|
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* __bitmap_parselist - convert list format ASCII string to bitmap
|
|
* @buf: read nul-terminated user string from this buffer
|
|
* @buflen: buffer size in bytes. If string is smaller than this
|
|
* then it must be terminated with a \0.
|
|
* @is_user: location of buffer, 0 indicates kernel space
|
|
* @maskp: 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.
|
|
* Optionally each range can be postfixed to denote that only parts of it
|
|
* should be set. The range will divided to groups of specific size.
|
|
* From each group will be used only defined amount of bits.
|
|
* Syntax: range:used_size/group_size
|
|
* Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
|
|
*
|
|
* 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
|
|
*/
|
|
static int __bitmap_parselist(const char *buf, unsigned int buflen,
|
|
int is_user, unsigned long *maskp,
|
|
int nmaskbits)
|
|
{
|
|
unsigned int a, b, old_a, old_b;
|
|
unsigned int group_size, used_size;
|
|
int c, old_c, totaldigits, ndigits;
|
|
const char __user __force *ubuf = (const char __user __force *)buf;
|
|
int at_start, in_range, in_partial_range;
|
|
|
|
totaldigits = c = 0;
|
|
old_a = old_b = 0;
|
|
group_size = used_size = 0;
|
|
bitmap_zero(maskp, nmaskbits);
|
|
do {
|
|
at_start = 1;
|
|
in_range = 0;
|
|
in_partial_range = 0;
|
|
a = b = 0;
|
|
ndigits = totaldigits;
|
|
|
|
/* Get the next cpu# or a range of cpu#'s */
|
|
while (buflen) {
|
|
old_c = c;
|
|
if (is_user) {
|
|
if (__get_user(c, ubuf++))
|
|
return -EFAULT;
|
|
} else
|
|
c = *buf++;
|
|
buflen--;
|
|
if (isspace(c))
|
|
continue;
|
|
|
|
/* A '\0' or a ',' signal the end of a cpu# or range */
|
|
if (c == '\0' || c == ',')
|
|
break;
|
|
/*
|
|
* whitespaces between digits are not allowed,
|
|
* but it's ok if whitespaces are on head or tail.
|
|
* when old_c is whilespace,
|
|
* if totaldigits == ndigits, whitespace is on head.
|
|
* if whitespace is on tail, it should not run here.
|
|
* as c was ',' or '\0',
|
|
* the last code line has broken the current loop.
|
|
*/
|
|
if ((totaldigits != ndigits) && isspace(old_c))
|
|
return -EINVAL;
|
|
|
|
if (c == '/') {
|
|
used_size = a;
|
|
at_start = 1;
|
|
in_range = 0;
|
|
a = b = 0;
|
|
continue;
|
|
}
|
|
|
|
if (c == ':') {
|
|
old_a = a;
|
|
old_b = b;
|
|
at_start = 1;
|
|
in_range = 0;
|
|
in_partial_range = 1;
|
|
a = b = 0;
|
|
continue;
|
|
}
|
|
|
|
if (c == '-') {
|
|
if (at_start || in_range)
|
|
return -EINVAL;
|
|
b = 0;
|
|
in_range = 1;
|
|
at_start = 1;
|
|
continue;
|
|
}
|
|
|
|
if (!isdigit(c))
|
|
return -EINVAL;
|
|
|
|
b = b * 10 + (c - '0');
|
|
if (!in_range)
|
|
a = b;
|
|
at_start = 0;
|
|
totaldigits++;
|
|
}
|
|
if (ndigits == totaldigits)
|
|
continue;
|
|
if (in_partial_range) {
|
|
group_size = a;
|
|
a = old_a;
|
|
b = old_b;
|
|
old_a = old_b = 0;
|
|
}
|
|
/* if no digit is after '-', it's wrong*/
|
|
if (at_start && in_range)
|
|
return -EINVAL;
|
|
if (!(a <= b) || !(used_size <= group_size))
|
|
return -EINVAL;
|
|
if (b >= nmaskbits)
|
|
return -ERANGE;
|
|
while (a <= b) {
|
|
if (in_partial_range) {
|
|
static int pos_in_group = 1;
|
|
|
|
if (pos_in_group <= used_size)
|
|
set_bit(a, maskp);
|
|
|
|
if (a == b || ++pos_in_group > group_size)
|
|
pos_in_group = 1;
|
|
} else
|
|
set_bit(a, maskp);
|
|
a++;
|
|
}
|
|
} while (buflen && c == ',');
|
|
return 0;
|
|
}
|
|
|
|
int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
|
|
{
|
|
char *nl = strchrnul(bp, '\n');
|
|
int len = nl - bp;
|
|
|
|
return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
|
|
}
|
|
EXPORT_SYMBOL(bitmap_parselist);
|
|
|
|
|
|
/**
|
|
* bitmap_parselist_user()
|
|
*
|
|
* @ubuf: pointer to user buffer containing string.
|
|
* @ulen: buffer size in bytes. If string is smaller than this
|
|
* then it must be terminated with a \0.
|
|
* @maskp: pointer to bitmap array that will contain result.
|
|
* @nmaskbits: size of bitmap, in bits.
|
|
*
|
|
* Wrapper for bitmap_parselist(), providing it with user buffer.
|
|
*
|
|
* We cannot have this as an inline function in bitmap.h because it needs
|
|
* linux/uaccess.h to get the access_ok() declaration and this causes
|
|
* cyclic dependencies.
|
|
*/
|
|
int bitmap_parselist_user(const char __user *ubuf,
|
|
unsigned int ulen, unsigned long *maskp,
|
|
int nmaskbits)
|
|
{
|
|
if (!access_ok(VERIFY_READ, ubuf, ulen))
|
|
return -EFAULT;
|
|
return __bitmap_parselist((const char __force *)ubuf,
|
|
ulen, 1, maskp, nmaskbits);
|
|
}
|
|
EXPORT_SYMBOL(bitmap_parselist_user);
|
|
|
|
|
|
/**
|
|
* bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
|
|
* @buf: pointer to a bitmap
|
|
* @pos: a bit position in @buf (0 <= @pos < @nbits)
|
|
* @nbits: number of valid bit positions in @buf
|
|
*
|
|
* Map the bit at position @pos in @buf (of length @nbits) 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 -1. 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, unsigned int pos, unsigned int nbits)
|
|
{
|
|
if (pos >= nbits || !test_bit(pos, buf))
|
|
return -1;
|
|
|
|
return __bitmap_weight(buf, pos);
|
|
}
|
|
|
|
/**
|
|
* bitmap_ord_to_pos - find position of n-th set bit in bitmap
|
|
* @buf: pointer to bitmap
|
|
* @ord: ordinal bit position (n-th set bit, n >= 0)
|
|
* @nbits: 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). If @ord
|
|
* >= weight(buf), returns @nbits.
|
|
*
|
|
* 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 returns @nbits. 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 @nbits-1 are valid positions in @buf.
|
|
*/
|
|
unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits)
|
|
{
|
|
unsigned int pos;
|
|
|
|
for (pos = find_first_bit(buf, nbits);
|
|
pos < nbits && ord;
|
|
pos = find_next_bit(buf, nbits, pos + 1))
|
|
ord--;
|
|
|
|
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
|
|
* @nbits: 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,
|
|
unsigned int nbits)
|
|
{
|
|
unsigned int oldbit, w;
|
|
|
|
if (dst == src) /* following doesn't handle inplace remaps */
|
|
return;
|
|
bitmap_zero(dst, nbits);
|
|
|
|
w = bitmap_weight(new, nbits);
|
|
for_each_set_bit(oldbit, src, nbits) {
|
|
int n = bitmap_pos_to_ord(old, oldbit, nbits);
|
|
|
|
if (n < 0 || w == 0)
|
|
set_bit(oldbit, dst); /* identity map */
|
|
else
|
|
set_bit(bitmap_ord_to_pos(new, n % w, nbits), 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);
|
|
|
|
/**
|
|
* bitmap_onto - translate one bitmap relative to another
|
|
* @dst: resulting translated bitmap
|
|
* @orig: original untranslated bitmap
|
|
* @relmap: bitmap relative to which translated
|
|
* @bits: number of bits in each of these bitmaps
|
|
*
|
|
* Set the n-th bit of @dst iff there exists some m such that the
|
|
* n-th bit of @relmap is set, the m-th bit of @orig is set, and
|
|
* the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
|
|
* (If you understood the previous sentence the first time your
|
|
* read it, you're overqualified for your current job.)
|
|
*
|
|
* In other words, @orig is mapped onto (surjectively) @dst,
|
|
* using the map { <n, m> | the n-th bit of @relmap is the
|
|
* m-th set bit of @relmap }.
|
|
*
|
|
* Any set bits in @orig above bit number W, where W is the
|
|
* weight of (number of set bits in) @relmap are mapped nowhere.
|
|
* In particular, if for all bits m set in @orig, m >= W, then
|
|
* @dst will end up empty. In situations where the possibility
|
|
* of such an empty result is not desired, one way to avoid it is
|
|
* to use the bitmap_fold() operator, below, to first fold the
|
|
* @orig bitmap over itself so that all its set bits x are in the
|
|
* range 0 <= x < W. The bitmap_fold() operator does this by
|
|
* setting the bit (m % W) in @dst, for each bit (m) set in @orig.
|
|
*
|
|
* Example [1] for bitmap_onto():
|
|
* Let's say @relmap has bits 30-39 set, and @orig has bits
|
|
* 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
|
|
* @dst will have bits 31, 33, 35, 37 and 39 set.
|
|
*
|
|
* When bit 0 is set in @orig, it means turn on the bit in
|
|
* @dst corresponding to whatever is the first bit (if any)
|
|
* that is turned on in @relmap. Since bit 0 was off in the
|
|
* above example, we leave off that bit (bit 30) in @dst.
|
|
*
|
|
* When bit 1 is set in @orig (as in the above example), it
|
|
* means turn on the bit in @dst corresponding to whatever
|
|
* is the second bit that is turned on in @relmap. The second
|
|
* bit in @relmap that was turned on in the above example was
|
|
* bit 31, so we turned on bit 31 in @dst.
|
|
*
|
|
* Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
|
|
* because they were the 4th, 6th, 8th and 10th set bits
|
|
* set in @relmap, and the 4th, 6th, 8th and 10th bits of
|
|
* @orig (i.e. bits 3, 5, 7 and 9) were also set.
|
|
*
|
|
* When bit 11 is set in @orig, it means turn on the bit in
|
|
* @dst corresponding to whatever is the twelfth bit that is
|
|
* turned on in @relmap. In the above example, there were
|
|
* only ten bits turned on in @relmap (30..39), so that bit
|
|
* 11 was set in @orig had no affect on @dst.
|
|
*
|
|
* Example [2] for bitmap_fold() + bitmap_onto():
|
|
* Let's say @relmap has these ten bits set::
|
|
*
|
|
* 40 41 42 43 45 48 53 61 74 95
|
|
*
|
|
* (for the curious, that's 40 plus the first ten terms of the
|
|
* Fibonacci sequence.)
|
|
*
|
|
* Further lets say we use the following code, invoking
|
|
* bitmap_fold() then bitmap_onto, as suggested above to
|
|
* avoid the possibility of an empty @dst result::
|
|
*
|
|
* unsigned long *tmp; // a temporary bitmap's bits
|
|
*
|
|
* bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
|
|
* bitmap_onto(dst, tmp, relmap, bits);
|
|
*
|
|
* Then this table shows what various values of @dst would be, for
|
|
* various @orig's. I list the zero-based positions of each set bit.
|
|
* The tmp column shows the intermediate result, as computed by
|
|
* using bitmap_fold() to fold the @orig bitmap modulo ten
|
|
* (the weight of @relmap):
|
|
*
|
|
* =============== ============== =================
|
|
* @orig tmp @dst
|
|
* 0 0 40
|
|
* 1 1 41
|
|
* 9 9 95
|
|
* 10 0 40 [#f1]_
|
|
* 1 3 5 7 1 3 5 7 41 43 48 61
|
|
* 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
|
|
* 0 9 18 27 0 9 8 7 40 61 74 95
|
|
* 0 10 20 30 0 40
|
|
* 0 11 22 33 0 1 2 3 40 41 42 43
|
|
* 0 12 24 36 0 2 4 6 40 42 45 53
|
|
* 78 102 211 1 2 8 41 42 74 [#f1]_
|
|
* =============== ============== =================
|
|
*
|
|
* .. [#f1]
|
|
*
|
|
* For these marked lines, if we hadn't first done bitmap_fold()
|
|
* into tmp, then the @dst result would have been empty.
|
|
*
|
|
* If either of @orig or @relmap is empty (no set bits), then @dst
|
|
* will be returned empty.
|
|
*
|
|
* If (as explained above) the only set bits in @orig are in positions
|
|
* m where m >= W, (where W is the weight of @relmap) then @dst will
|
|
* once again be returned empty.
|
|
*
|
|
* All bits in @dst not set by the above rule are cleared.
|
|
*/
|
|
void bitmap_onto(unsigned long *dst, const unsigned long *orig,
|
|
const unsigned long *relmap, unsigned int bits)
|
|
{
|
|
unsigned int n, m; /* same meaning as in above comment */
|
|
|
|
if (dst == orig) /* following doesn't handle inplace mappings */
|
|
return;
|
|
bitmap_zero(dst, bits);
|
|
|
|
/*
|
|
* The following code is a more efficient, but less
|
|
* obvious, equivalent to the loop:
|
|
* for (m = 0; m < bitmap_weight(relmap, bits); m++) {
|
|
* n = bitmap_ord_to_pos(orig, m, bits);
|
|
* if (test_bit(m, orig))
|
|
* set_bit(n, dst);
|
|
* }
|
|
*/
|
|
|
|
m = 0;
|
|
for_each_set_bit(n, relmap, bits) {
|
|
/* m == bitmap_pos_to_ord(relmap, n, bits) */
|
|
if (test_bit(m, orig))
|
|
set_bit(n, dst);
|
|
m++;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(bitmap_onto);
|
|
|
|
/**
|
|
* bitmap_fold - fold larger bitmap into smaller, modulo specified size
|
|
* @dst: resulting smaller bitmap
|
|
* @orig: original larger bitmap
|
|
* @sz: specified size
|
|
* @nbits: number of bits in each of these bitmaps
|
|
*
|
|
* For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
|
|
* Clear all other bits in @dst. See further the comment and
|
|
* Example [2] for bitmap_onto() for why and how to use this.
|
|
*/
|
|
void bitmap_fold(unsigned long *dst, const unsigned long *orig,
|
|
unsigned int sz, unsigned int nbits)
|
|
{
|
|
unsigned int oldbit;
|
|
|
|
if (dst == orig) /* following doesn't handle inplace mappings */
|
|
return;
|
|
bitmap_zero(dst, nbits);
|
|
|
|
for_each_set_bit(oldbit, orig, nbits)
|
|
set_bit(oldbit % sz, dst);
|
|
}
|
|
EXPORT_SYMBOL(bitmap_fold);
|
|
|
|
/*
|
|
* 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, unsigned 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, unsigned int bits, int order)
|
|
{
|
|
unsigned int pos, end; /* scans bitmap by regions of size order */
|
|
|
|
for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
|
|
if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
|
|
continue;
|
|
__reg_op(bitmap, pos, order, REG_OP_ALLOC);
|
|
return pos;
|
|
}
|
|
return -ENOMEM;
|
|
}
|
|
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, unsigned 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, unsigned int pos, int order)
|
|
{
|
|
if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
|
|
return -EBUSY;
|
|
return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
|
|
}
|
|
EXPORT_SYMBOL(bitmap_allocate_region);
|
|
|
|
/**
|
|
* bitmap_from_u32array - copy the contents of a u32 array of bits to bitmap
|
|
* @bitmap: array of unsigned longs, the destination bitmap, non NULL
|
|
* @nbits: number of bits in @bitmap
|
|
* @buf: array of u32 (in host byte order), the source bitmap, non NULL
|
|
* @nwords: number of u32 words in @buf
|
|
*
|
|
* copy min(nbits, 32*nwords) bits from @buf to @bitmap, remaining
|
|
* bits between nword and nbits in @bitmap (if any) are cleared. In
|
|
* last word of @bitmap, the bits beyond nbits (if any) are kept
|
|
* unchanged.
|
|
*
|
|
* Return the number of bits effectively copied.
|
|
*/
|
|
unsigned int
|
|
bitmap_from_u32array(unsigned long *bitmap, unsigned int nbits,
|
|
const u32 *buf, unsigned int nwords)
|
|
{
|
|
unsigned int dst_idx, src_idx;
|
|
|
|
for (src_idx = dst_idx = 0; dst_idx < BITS_TO_LONGS(nbits); ++dst_idx) {
|
|
unsigned long part = 0;
|
|
|
|
if (src_idx < nwords)
|
|
part = buf[src_idx++];
|
|
|
|
#if BITS_PER_LONG == 64
|
|
if (src_idx < nwords)
|
|
part |= ((unsigned long) buf[src_idx++]) << 32;
|
|
#endif
|
|
|
|
if (dst_idx < nbits/BITS_PER_LONG)
|
|
bitmap[dst_idx] = part;
|
|
else {
|
|
unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
|
|
|
|
bitmap[dst_idx] = (bitmap[dst_idx] & ~mask)
|
|
| (part & mask);
|
|
}
|
|
}
|
|
|
|
return min_t(unsigned int, nbits, 32*nwords);
|
|
}
|
|
EXPORT_SYMBOL(bitmap_from_u32array);
|
|
|
|
/**
|
|
* bitmap_to_u32array - copy the contents of bitmap to a u32 array of bits
|
|
* @buf: array of u32 (in host byte order), the dest bitmap, non NULL
|
|
* @nwords: number of u32 words in @buf
|
|
* @bitmap: array of unsigned longs, the source bitmap, non NULL
|
|
* @nbits: number of bits in @bitmap
|
|
*
|
|
* copy min(nbits, 32*nwords) bits from @bitmap to @buf. Remaining
|
|
* bits after nbits in @buf (if any) are cleared.
|
|
*
|
|
* Return the number of bits effectively copied.
|
|
*/
|
|
unsigned int
|
|
bitmap_to_u32array(u32 *buf, unsigned int nwords,
|
|
const unsigned long *bitmap, unsigned int nbits)
|
|
{
|
|
unsigned int dst_idx = 0, src_idx = 0;
|
|
|
|
while (dst_idx < nwords) {
|
|
unsigned long part = 0;
|
|
|
|
if (src_idx < BITS_TO_LONGS(nbits)) {
|
|
part = bitmap[src_idx];
|
|
if (src_idx >= nbits/BITS_PER_LONG)
|
|
part &= BITMAP_LAST_WORD_MASK(nbits);
|
|
src_idx++;
|
|
}
|
|
|
|
buf[dst_idx++] = part & 0xffffffffUL;
|
|
|
|
#if BITS_PER_LONG == 64
|
|
if (dst_idx < nwords) {
|
|
part >>= 32;
|
|
buf[dst_idx++] = part & 0xffffffffUL;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
return min_t(unsigned int, nbits, 32*nwords);
|
|
}
|
|
EXPORT_SYMBOL(bitmap_to_u32array);
|
|
|
|
/**
|
|
* bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
|
|
* @dst: destination buffer
|
|
* @src: bitmap to copy
|
|
* @nbits: number of bits in the bitmap
|
|
*
|
|
* Require nbits % BITS_PER_LONG == 0.
|
|
*/
|
|
#ifdef __BIG_ENDIAN
|
|
void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < nbits/BITS_PER_LONG; i++) {
|
|
if (BITS_PER_LONG == 64)
|
|
dst[i] = cpu_to_le64(src[i]);
|
|
else
|
|
dst[i] = cpu_to_le32(src[i]);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(bitmap_copy_le);
|
|
#endif
|