976e741c59
Import __bitmap_parselist from the Linux kernel, in order to parse CPU ranges as used in eg. the kernel isolcpus= commandline argument. This code appears to have been in the Linux kernel since the initial git import in 2005, so I do not have attribution of which changeset(s) introduced it into the kernel. Signed-off-by: Rik van Riel <riel@redhat.com>
464 lines
12 KiB
C
464 lines
12 KiB
C
/*
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This file is taken from the Linux kernel and minimally adapted for use in userspace
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*/
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/*
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* lib/bitmap.c
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* Helper functions for bitmap.h.
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include "config.h"
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#include <unistd.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include "bitmap.h"
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#include "non-atomic.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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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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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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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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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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/*
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* __bitmap_shift_right - logical right shift of the bits in a bitmap
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* @dst - destination bitmap
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* @src - source bitmap
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* @nbits - shift by this many bits
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* @bits - bitmap size, in bits
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*
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* Shifting right (dividing) means moving bits in the MS -> LS bit
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* direction. Zeros are fed into the vacated MS positions and the
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* LS bits shifted off the bottom are lost.
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*/
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void __bitmap_shift_right(unsigned long *dst,
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const unsigned long *src, int shift, int bits)
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{
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int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
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int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
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unsigned long mask = (1UL << left) - 1;
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for (k = 0; off + k < lim; ++k) {
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unsigned long upper, lower;
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/*
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* If shift is not word aligned, take lower rem bits of
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* word above and make them the top rem bits of result.
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*/
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if (!rem || off + k + 1 >= lim)
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upper = 0;
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else {
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upper = src[off + k + 1];
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if (off + k + 1 == lim - 1 && left)
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upper &= mask;
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}
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lower = src[off + k];
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if (left && off + k == lim - 1)
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lower &= mask;
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dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
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if (left && k == lim - 1)
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dst[k] &= mask;
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}
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if (off)
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memset(&dst[lim - off], 0, off*sizeof(unsigned long));
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}
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/*
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* __bitmap_shift_left - logical left shift of the bits in a bitmap
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* @dst - destination bitmap
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* @src - source bitmap
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* @nbits - shift by this many bits
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* @bits - bitmap size, in bits
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*
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* Shifting left (multiplying) means moving bits in the LS -> MS
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* direction. Zeros are fed into the vacated LS bit positions
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* and those MS bits shifted off the top are lost.
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*/
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void __bitmap_shift_left(unsigned long *dst,
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const unsigned long *src, int shift, int bits)
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{
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int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
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int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
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for (k = lim - off - 1; k >= 0; --k) {
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unsigned long upper, lower;
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/*
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* If shift is not word aligned, take upper rem bits of
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* word below and make them the bottom rem bits of result.
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*/
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if (rem && k > 0)
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lower = src[k - 1];
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else
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lower = 0;
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upper = src[k];
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if (left && k == lim - 1)
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upper &= (1UL << left) - 1;
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dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
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if (left && k + off == lim - 1)
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dst[k + off] &= (1UL << left) - 1;
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}
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if (off)
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memset(dst, 0, off*sizeof(unsigned long));
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}
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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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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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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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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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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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/*
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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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uint32_t chunkmask;
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int first = 1;
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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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if (val!=0 || !first || i==0) {
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len += snprintf(buf+len, buflen-len, "%s%0*lx", sep,
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(chunksz+3)/4, val);
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sep = ",";
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first = 0;
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}
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chunksz = CHUNKSZ;
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}
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return len;
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}
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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 __attribute((unused)), 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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uint32_t chunk;
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bitmap_zero(maskp, nmaskbits);
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nchunks = nbits = totaldigits = c = 0;
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do {
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chunk = ndigits = 0;
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/* Get the next chunk of the bitmap */
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while (buflen) {
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old_c = c;
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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 0;
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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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/**
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* __bitmap_parselist - convert list format ASCII string to bitmap
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* @buf: read nul-terminated user string from this buffer
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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: 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
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* decimal numbers, the smallest and largest bit numbers set in
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* the range.
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*
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* Returns 0 on success, -errno on invalid input strings.
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* Error values:
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* %-EINVAL: second number in range smaller than first
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* %-EINVAL: invalid character in string
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* %-ERANGE: bit number specified too large for mask
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*/
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int __bitmap_parselist(const char *buf, unsigned int buflen,
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int is_user __attribute((unused)), unsigned long *maskp,
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int nmaskbits)
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{
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int a, b, c, old_c, totaldigits;
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int exp_digit, in_range;
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totaldigits = c = 0;
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bitmap_zero(maskp, nmaskbits);
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do {
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exp_digit = 1;
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in_range = 0;
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a = b = 0;
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/* Get the next cpu# or a range of cpu#'s */
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while (buflen) {
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old_c = c;
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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 a cpu# or range */
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if (c == '\0' || c == ',')
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break;
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if (c == '-') {
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if (exp_digit || in_range)
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return -EINVAL;
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b = 0;
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in_range = 1;
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exp_digit = 1;
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continue;
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}
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if (!isdigit(c))
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return -EINVAL;
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b = b * 10 + (c - '0');
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if (!in_range)
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a = b;
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exp_digit = 0;
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totaldigits++;
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}
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if (!(a <= b))
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return -EINVAL;
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if (b >= nmaskbits)
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return -ERANGE;
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while (a <= b) {
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set_bit(a, maskp);
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a++;
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}
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} while (buflen && c == ',');
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return 0;
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}
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