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lib/bitmap.c
36 KB
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// SPDX-License-Identifier: GPL-2.0-only |
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/* * lib/bitmap.c * Helper functions for bitmap.h. |
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*/ |
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#include <linux/export.h> #include <linux/thread_info.h> |
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#include <linux/ctype.h> #include <linux/errno.h> #include <linux/bitmap.h> #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/mm.h> |
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#include <linux/slab.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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#include "kstrtox.h" |
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/** * DOC: bitmap introduction * |
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* bitmaps provide an array of bits, implemented using an an * array of unsigned longs. The number of valid bits in a * given bitmap does _not_ need to be an exact multiple of * BITS_PER_LONG. * * The possible unused bits in the last, partially used word * of a bitmap are 'don't care'. The implementation makes * no particular effort to keep them zero. It ensures that * their value will not affect the results of any operation. * The bitmap operations that return Boolean (bitmap_empty, * for example) or scalar (bitmap_weight, for example) results * carefully filter out these unused bits from impacting their * results. * |
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* The byte ordering of bitmaps is more natural on little * endian architectures. See the big-endian headers * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h * for the best explanations of this ordering. */ |
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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) if (bitmap1[k] != bitmap2[k]) return 0; if (bits % BITS_PER_LONG) if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) return 0; return 1; } EXPORT_SYMBOL(__bitmap_equal); |
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bool __bitmap_or_equal(const unsigned long *bitmap1, const unsigned long *bitmap2, const unsigned long *bitmap3, unsigned int bits) { unsigned int k, lim = bits / BITS_PER_LONG; unsigned long tmp; for (k = 0; k < lim; ++k) { if ((bitmap1[k] | bitmap2[k]) != bitmap3[k]) return false; } if (!(bits % BITS_PER_LONG)) return true; tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k]; return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0; } |
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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_TO_LONGS(bits); |
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for (k = 0; k < lim; ++k) dst[k] = ~src[k]; |
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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 * @src : source bitmap * @shift : shift by this many bits |
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* @nbits : bitmap size, in bits |
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* * Shifting right (dividing) means moving bits in the MS -> LS bit * direction. Zeros are fed into the vacated MS positions and the * LS bits shifted off the bottom are lost. */ |
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void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, 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) { unsigned long upper, lower; /* * If shift is not word aligned, take lower rem bits of * word above and make them the top rem bits of result. */ if (!rem || off + k + 1 >= lim) upper = 0; else { 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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} 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; dst[k] = lower | upper; |
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} if (off) memset(&dst[lim - off], 0, off*sizeof(unsigned long)); } 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 * @src : source bitmap * @shift : shift by this many bits |
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* @nbits : bitmap size, in bits |
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* * Shifting left (multiplying) means moving bits in the LS -> MS * direction. Zeros are fed into the vacated LS bit positions * and those MS bits shifted off the top are lost. */ |
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void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, 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) { unsigned long upper, lower; /* * If shift is not word aligned, take upper rem bits of * word below and make them the bottom rem bits of result. */ if (rem && k > 0) |
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lower = src[k - 1] >> (BITS_PER_LONG - rem); |
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else lower = 0; |
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upper = src[k] << rem; |
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dst[k + off] = lower | upper; |
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} if (off) memset(dst, 0, off*sizeof(unsigned long)); } 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) result |= (dst[k] = bitmap1[k] & bitmap2[k] & BITMAP_LAST_WORD_MASK(bits)); |
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return result != 0; |
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} EXPORT_SYMBOL(__bitmap_and); 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; unsigned int nr = BITS_TO_LONGS(bits); |
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for (k = 0; k < nr; k++) dst[k] = bitmap1[k] | bitmap2[k]; } EXPORT_SYMBOL(__bitmap_or); 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; unsigned int nr = BITS_TO_LONGS(bits); |
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for (k = 0; k < nr; k++) dst[k] = bitmap1[k] ^ bitmap2[k]; } 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) result |= (dst[k] = bitmap1[k] & ~bitmap2[k] & BITMAP_LAST_WORD_MASK(bits)); |
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return result != 0; |
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} EXPORT_SYMBOL(__bitmap_andnot); 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) if (bitmap1[k] & bitmap2[k]) return 1; if (bits % BITS_PER_LONG) if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) return 1; return 0; } EXPORT_SYMBOL(__bitmap_intersects); 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) if (bitmap1[k] & ~bitmap2[k]) return 0; if (bits % BITS_PER_LONG) if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) return 0; return 1; } 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; 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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EXPORT_SYMBOL(__bitmap_weight); |
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void __bitmap_set(unsigned long *map, unsigned int start, int len) |
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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); 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; mask_to_set = ~0UL; p++; } |
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if (len) { |
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mask_to_set &= BITMAP_LAST_WORD_MASK(size); *p |= mask_to_set; } } |
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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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{ 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); 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; mask_to_clear = ~0UL; p++; } |
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if (len) { |
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mask_to_clear &= BITMAP_LAST_WORD_MASK(size); *p &= ~mask_to_clear; } } |
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EXPORT_SYMBOL(__bitmap_clear); |
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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 * @size: The bitmap size in bits * @start: The bitnumber to start searching at * @nr: The number of zeroed bits we're looking for * @align_mask: Alignment mask for zero area |
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* @align_offset: Alignment offset for zero area. |
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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 * 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, unsigned long size, unsigned long start, unsigned int nr, unsigned long align_mask, unsigned long align_offset) |
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{ unsigned long index, end, i; again: index = find_next_zero_bit(map, size, start); /* Align allocation */ |
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index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset; |
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end = index + nr; if (end > size) return end; i = find_next_bit(map, end, index); if (i < end) { start = i + 1; goto again; } return index; } |
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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. */ #define CHUNKSZ 32 #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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* __bitmap_parse - convert an ASCII hex string into a bitmap. * @buf: pointer to buffer containing string. * @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. * @nmaskbits: size of bitmap, in bits. * * Commas group hex digits into chunks. Each chunk defines exactly 32 * 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 * 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 "". * Leading and trailing whitespace accepted, but not embedded whitespace. */ |
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int __bitmap_parse(const char *buf, unsigned int buflen, int is_user, unsigned long *maskp, int nmaskbits) |
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{ int c, old_c, totaldigits, ndigits, nchunks, nbits; u32 chunk; |
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const char __user __force *ubuf = (const char __user __force *)buf; |
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bitmap_zero(maskp, nmaskbits); nchunks = nbits = totaldigits = c = 0; do { |
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chunk = 0; 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) { if (__get_user(c, ubuf++)) return -EFAULT; } else c = *buf++; buflen--; |
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if (isspace(c)) continue; /* * If the last character was a space and the current * character isn't '\0', we've got embedded whitespace. * This is a no-no, so throw an error. */ if (totaldigits && c && isspace(old_c)) return -EINVAL; /* A '\0' or a ',' signal the end of the chunk */ if (c == '\0' || c == ',') break; if (!isxdigit(c)) return -EINVAL; /* * Make sure there are at least 4 free bits in 'chunk'. * If not, this hexdigit will overflow 'chunk', so * throw an error. */ if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1)) return -EOVERFLOW; |
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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; if (nchunks == 0 && chunk == 0) continue; __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); *maskp |= chunk; nchunks++; nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ; if (nbits > nmaskbits) return -EOVERFLOW; |
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} while (buflen && c == ','); |
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return 0; } |
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EXPORT_SYMBOL(__bitmap_parse); /** |
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* bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap |
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* * @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_parse(), 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_parse_user(const char __user *ubuf, unsigned int ulen, unsigned long *maskp, int nmaskbits) { |
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if (!access_ok(ubuf, ulen)) |
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return -EFAULT; |
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return __bitmap_parse((const char __force *)ubuf, ulen, 1, maskp, nmaskbits); |
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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 * @list: indicates whether the bitmap must be list * @buf: page aligned buffer into which string is placed * @maskp: pointer to bitmap to convert * @nmaskbits: size of bitmap, in bits * * Output format is a comma-separated list of decimal numbers and * ranges if list is specified or hex digits grouped into comma-separated * 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, page-aligned * area and that sufficient storage remains at @buf to accommodate the * bitmap_print_to_pagebuf() output. Returns the number of characters * actually printed to @buf, excluding terminating '\0'. |
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*/ int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, int nmaskbits) { |
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ptrdiff_t len = PAGE_SIZE - offset_in_page(buf); |
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return list ? scnprintf(buf, len, "%*pbl ", nmaskbits, maskp) : scnprintf(buf, len, "%*pb ", nmaskbits, maskp); |
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} EXPORT_SYMBOL(bitmap_print_to_pagebuf); |
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485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 |
/* * Region 9-38:4/10 describes the following bitmap structure: * 0 9 12 18 38 * .........****......****......****...... * ^ ^ ^ ^ * start off group_len end */ struct region { unsigned int start; unsigned int off; unsigned int group_len; unsigned int end; }; static int bitmap_set_region(const struct region *r, unsigned long *bitmap, int nbits) { unsigned int start; if (r->end >= nbits) return -ERANGE; for (start = r->start; start <= r->end; start += r->group_len) bitmap_set(bitmap, start, min(r->end - start + 1, r->off)); return 0; } static int bitmap_check_region(const struct region *r) { if (r->start > r->end || r->group_len == 0 || r->off > r->group_len) return -EINVAL; return 0; } static const char *bitmap_getnum(const char *str, unsigned int *num) { unsigned long long n; unsigned int len; len = _parse_integer(str, 10, &n); if (!len) return ERR_PTR(-EINVAL); if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n) return ERR_PTR(-EOVERFLOW); *num = n; return str + len; } static inline bool end_of_str(char c) { return c == '\0' || c == ' '; } static inline bool __end_of_region(char c) { return isspace(c) || c == ','; } static inline bool end_of_region(char c) { return __end_of_region(c) || end_of_str(c); } /* * The format allows commas and whitespases at the beginning * of the region. */ static const char *bitmap_find_region(const char *str) { while (__end_of_region(*str)) str++; return end_of_str(*str) ? NULL : str; } static const char *bitmap_parse_region(const char *str, struct region *r) { str = bitmap_getnum(str, &r->start); if (IS_ERR(str)) return str; if (end_of_region(*str)) goto no_end; if (*str != '-') return ERR_PTR(-EINVAL); str = bitmap_getnum(str + 1, &r->end); if (IS_ERR(str)) return str; if (end_of_region(*str)) goto no_pattern; if (*str != ':') return ERR_PTR(-EINVAL); str = bitmap_getnum(str + 1, &r->off); if (IS_ERR(str)) return str; if (*str != '/') return ERR_PTR(-EINVAL); return bitmap_getnum(str + 1, &r->group_len); no_end: r->end = r->start; no_pattern: r->off = r->end + 1; r->group_len = r->end + 1; return end_of_str(*str) ? NULL : str; } |
5aaba3631
|
603 |
/** |
e371c481d
|
604 605 606 607 |
* bitmap_parselist - convert list format ASCII string to bitmap * @buf: read user string from this buffer; must be terminated * with a \0 or . |
6e1907ffd
|
608 |
* @maskp: write resulting mask here |
1da177e4c
|
609 610 611 612 613 614 |
* @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. |
2d13e6ca4
|
615 616 617 618 619 |
* 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 |
1da177e4c
|
620 |
* |
40bf19a8d
|
621 622 |
* Returns: 0 on success, -errno on invalid input strings. Error values: * |
e371c481d
|
623 |
* - ``-EINVAL``: wrong region format |
40bf19a8d
|
624 625 |
* - ``-EINVAL``: invalid character in string * - ``-ERANGE``: bit number specified too large for mask |
e371c481d
|
626 |
* - ``-EOVERFLOW``: integer overflow in the input parameters |
1da177e4c
|
627 |
*/ |
e371c481d
|
628 |
int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits) |
1da177e4c
|
629 |
{ |
e371c481d
|
630 631 |
struct region r; long ret; |
1da177e4c
|
632 633 |
bitmap_zero(maskp, nmaskbits); |
4b060420a
|
634 |
|
e371c481d
|
635 636 637 638 |
while (buf) { buf = bitmap_find_region(buf); if (buf == NULL) return 0; |
2d13e6ca4
|
639 |
|
e371c481d
|
640 641 642 |
buf = bitmap_parse_region(buf, &r); if (IS_ERR(buf)) return PTR_ERR(buf); |
2d13e6ca4
|
643 |
|
e371c481d
|
644 645 646 |
ret = bitmap_check_region(&r); if (ret) return ret; |
4b060420a
|
647 |
|
e371c481d
|
648 649 650 651 |
ret = bitmap_set_region(&r, maskp, nmaskbits); if (ret) return ret; } |
4b060420a
|
652 |
|
1da177e4c
|
653 654 655 |
return 0; } EXPORT_SYMBOL(bitmap_parselist); |
4b060420a
|
656 657 658 659 660 661 662 663 664 665 666 |
/** * 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. |
4b060420a
|
667 668 669 670 671 |
*/ int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen, unsigned long *maskp, int nmaskbits) { |
281327c99
|
672 673 674 675 676 677 678 679 680 681 682 |
char *buf; int ret; buf = memdup_user_nul(ubuf, ulen); if (IS_ERR(buf)) return PTR_ERR(buf); ret = bitmap_parselist(buf, maskp, nmaskbits); kfree(buf); return ret; |
4b060420a
|
683 684 |
} EXPORT_SYMBOL(bitmap_parselist_user); |
cdc90a187
|
685 |
#ifdef CONFIG_NUMA |
72fd4a35a
|
686 |
/** |
9a86e2bad
|
687 |
* bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap |
fb5eeeee4
|
688 |
* @buf: pointer to a bitmap |
df1d80a9e
|
689 690 |
* @pos: a bit position in @buf (0 <= @pos < @nbits) * @nbits: number of valid bit positions in @buf |
fb5eeeee4
|
691 |
* |
df1d80a9e
|
692 |
* Map the bit at position @pos in @buf (of length @nbits) to the |
fb5eeeee4
|
693 |
* ordinal of which set bit it is. If it is not set or if @pos |
96b7f3414
|
694 |
* is not a valid bit position, map to -1. |
fb5eeeee4
|
695 696 697 |
* * 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, |
a85517487
|
698 |
* and other @pos values will get mapped to -1. When @pos value 7 |
fb5eeeee4
|
699 700 701 702 703 |
* 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. */ |
df1d80a9e
|
704 |
static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits) |
fb5eeeee4
|
705 |
{ |
df1d80a9e
|
706 |
if (pos >= nbits || !test_bit(pos, buf)) |
96b7f3414
|
707 |
return -1; |
fb5eeeee4
|
708 |
|
df1d80a9e
|
709 |
return __bitmap_weight(buf, pos); |
fb5eeeee4
|
710 711 712 |
} /** |
9a86e2bad
|
713 |
* bitmap_ord_to_pos - find position of n-th set bit in bitmap |
fb5eeeee4
|
714 715 |
* @buf: pointer to bitmap * @ord: ordinal bit position (n-th set bit, n >= 0) |
f6a1f5db8
|
716 |
* @nbits: number of valid bit positions in @buf |
fb5eeeee4
|
717 718 |
* * Map the ordinal offset of bit @ord in @buf to its position in @buf. |
f6a1f5db8
|
719 720 |
* Value of @ord should be in range 0 <= @ord < weight(buf). If @ord * >= weight(buf), returns @nbits. |
fb5eeeee4
|
721 722 723 |
* * 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, |
f6a1f5db8
|
724 |
* and all other @ord values returns @nbits. When @ord value 3 |
fb5eeeee4
|
725 726 727 |
* 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. * |
f6a1f5db8
|
728 |
* The bit positions 0 through @nbits-1 are valid positions in @buf. |
fb5eeeee4
|
729 |
*/ |
f6a1f5db8
|
730 |
unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits) |
fb5eeeee4
|
731 |
{ |
f6a1f5db8
|
732 |
unsigned int pos; |
fb5eeeee4
|
733 |
|
f6a1f5db8
|
734 735 736 737 |
for (pos = find_first_bit(buf, nbits); pos < nbits && ord; pos = find_next_bit(buf, nbits, pos + 1)) ord--; |
fb5eeeee4
|
738 739 740 741 742 743 |
return pos; } /** * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap |
fb5eeeee4
|
744 |
* @dst: remapped result |
96b7f3414
|
745 |
* @src: subset to be remapped |
fb5eeeee4
|
746 747 |
* @old: defines domain of map * @new: defines range of map |
9814ec135
|
748 |
* @nbits: number of bits in each of these bitmaps |
fb5eeeee4
|
749 750 751 752 753 754 755 756 |
* * 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. * |
96b7f3414
|
757 758 759 |
* 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. |
fb5eeeee4
|
760 |
* |
96b7f3414
|
761 762 |
* The positions of unset bits in @old are mapped to themselves * (the identify map). |
fb5eeeee4
|
763 764 765 766 |
* * Apply the above specified mapping to @src, placing the result in * @dst, clearing any bits previously set in @dst. * |
fb5eeeee4
|
767 768 769 |
* 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 |
96b7f3414
|
770 771 772 |
* 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. |
fb5eeeee4
|
773 774 775 |
*/ void bitmap_remap(unsigned long *dst, const unsigned long *src, const unsigned long *old, const unsigned long *new, |
9814ec135
|
776 |
unsigned int nbits) |
fb5eeeee4
|
777 |
{ |
9814ec135
|
778 |
unsigned int oldbit, w; |
fb5eeeee4
|
779 |
|
fb5eeeee4
|
780 781 |
if (dst == src) /* following doesn't handle inplace remaps */ return; |
9814ec135
|
782 |
bitmap_zero(dst, nbits); |
96b7f3414
|
783 |
|
9814ec135
|
784 785 786 |
w = bitmap_weight(new, nbits); for_each_set_bit(oldbit, src, nbits) { int n = bitmap_pos_to_ord(old, oldbit, nbits); |
08564fb7a
|
787 |
|
96b7f3414
|
788 789 790 |
if (n < 0 || w == 0) set_bit(oldbit, dst); /* identity map */ else |
9814ec135
|
791 |
set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst); |
fb5eeeee4
|
792 793 |
} } |
fb5eeeee4
|
794 795 796 |
/** * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit |
6e1907ffd
|
797 798 799 800 |
* @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 |
fb5eeeee4
|
801 802 803 804 805 806 807 808 |
* * 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. * |
96b7f3414
|
809 810 |
* The positions of unset bits in @old are mapped to themselves * (the identify map). |
fb5eeeee4
|
811 812 813 814 815 816 817 |
* * 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 |
96b7f3414
|
818 819 |
* bit positions unchanged. So if say @oldbit is 5, then this routine * returns 13. |
fb5eeeee4
|
820 821 822 823 |
*/ int bitmap_bitremap(int oldbit, const unsigned long *old, const unsigned long *new, int bits) { |
96b7f3414
|
824 825 826 827 828 829 |
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); |
fb5eeeee4
|
830 |
} |
fb5eeeee4
|
831 |
|
7ea931c9f
|
832 833 834 835 836 837 838 839 840 841 842 843 844 845 |
/** * 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, |
da3dae54e
|
846 |
* using the map { <n, m> | the n-th bit of @relmap is the |
7ea931c9f
|
847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 |
* 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 |
25985edce
|
881 |
* @dst corresponding to whatever is the twelfth bit that is |
7ea931c9f
|
882 883 884 885 886 |
* 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(): |
40bf19a8d
|
887 888 |
* Let's say @relmap has these ten bits set:: * |
7ea931c9f
|
889 |
* 40 41 42 43 45 48 53 61 74 95 |
40bf19a8d
|
890 |
* |
7ea931c9f
|
891 892 893 894 895 |
* (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 |
40bf19a8d
|
896 |
* avoid the possibility of an empty @dst result:: |
7ea931c9f
|
897 898 899 900 901 902 903 904 905 906 |
* * 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 |
40bf19a8d
|
907 |
* (the weight of @relmap): |
7ea931c9f
|
908 |
* |
40bf19a8d
|
909 |
* =============== ============== ================= |
7ea931c9f
|
910 911 912 913 |
* @orig tmp @dst * 0 0 40 * 1 1 41 * 9 9 95 |
40bf19a8d
|
914 |
* 10 0 40 [#f1]_ |
7ea931c9f
|
915 916 917 918 919 920 |
* 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 |
40bf19a8d
|
921 922 923 924 |
* 78 102 211 1 2 8 41 42 74 [#f1]_ * =============== ============== ================= * * .. [#f1] |
7ea931c9f
|
925 |
* |
40bf19a8d
|
926 |
* For these marked lines, if we hadn't first done bitmap_fold() |
7ea931c9f
|
927 928 929 930 931 932 933 934 935 936 937 938 |
* 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, |
eb5698837
|
939 |
const unsigned long *relmap, unsigned int bits) |
7ea931c9f
|
940 |
{ |
eb5698837
|
941 |
unsigned int n, m; /* same meaning as in above comment */ |
7ea931c9f
|
942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 |
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; |
08564fb7a
|
958 |
for_each_set_bit(n, relmap, bits) { |
7ea931c9f
|
959 960 961 962 963 964 |
/* m == bitmap_pos_to_ord(relmap, n, bits) */ if (test_bit(m, orig)) set_bit(n, dst); m++; } } |
7ea931c9f
|
965 966 967 968 969 970 |
/** * bitmap_fold - fold larger bitmap into smaller, modulo specified size * @dst: resulting smaller bitmap * @orig: original larger bitmap * @sz: specified size |
b26ad5836
|
971 |
* @nbits: number of bits in each of these bitmaps |
7ea931c9f
|
972 973 974 975 976 977 |
* * 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, |
b26ad5836
|
978 |
unsigned int sz, unsigned int nbits) |
7ea931c9f
|
979 |
{ |
b26ad5836
|
980 |
unsigned int oldbit; |
7ea931c9f
|
981 982 983 |
if (dst == orig) /* following doesn't handle inplace mappings */ return; |
b26ad5836
|
984 |
bitmap_zero(dst, nbits); |
7ea931c9f
|
985 |
|
b26ad5836
|
986 |
for_each_set_bit(oldbit, orig, nbits) |
7ea931c9f
|
987 988 |
set_bit(oldbit % sz, dst); } |
cdc90a187
|
989 |
#endif /* CONFIG_NUMA */ |
7ea931c9f
|
990 |
|
3cf64b933
|
991 992 993 994 995 996 |
/* * 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 |
1da177e4c
|
997 |
* |
3cf64b933
|
998 999 |
* Can set, verify and/or release a region of bits in a bitmap, * depending on which combination of REG_OP_* flag bits is set. |
1da177e4c
|
1000 |
* |
3cf64b933
|
1001 1002 1003 1004 1005 1006 |
* 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. |
1da177e4c
|
1007 |
*/ |
3cf64b933
|
1008 1009 1010 1011 1012 1013 |
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 */ }; |
9279d3286
|
1014 |
static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op) |
1da177e4c
|
1015 |
{ |
3cf64b933
|
1016 1017 1018 1019 |
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 */ |
74373c6ac
|
1020 |
int nbitsinlong; /* num bits of region in each spanned long */ |
3cf64b933
|
1021 |
unsigned long mask; /* bitmask for one long of region */ |
74373c6ac
|
1022 |
int i; /* scans bitmap by longs */ |
3cf64b933
|
1023 |
int ret = 0; /* return value */ |
74373c6ac
|
1024 |
|
3cf64b933
|
1025 1026 1027 1028 1029 1030 1031 1032 1033 |
/* * 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); |
1da177e4c
|
1034 |
|
3cf64b933
|
1035 1036 1037 1038 |
/* * Can't do "mask = (1UL << nbitsinlong) - 1", as that * overflows if nbitsinlong == BITS_PER_LONG. */ |
74373c6ac
|
1039 |
mask = (1UL << (nbitsinlong - 1)); |
1da177e4c
|
1040 |
mask += mask - 1; |
3cf64b933
|
1041 |
mask <<= offset; |
1da177e4c
|
1042 |
|
3cf64b933
|
1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 |
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; |
1da177e4c
|
1061 |
} |
3cf64b933
|
1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 |
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. */ |
9279d3286
|
1080 |
int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order) |
3cf64b933
|
1081 |
{ |
9279d3286
|
1082 |
unsigned int pos, end; /* scans bitmap by regions of size order */ |
aa8e4fc68
|
1083 |
|
9279d3286
|
1084 |
for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) { |
aa8e4fc68
|
1085 1086 1087 1088 1089 1090 |
if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) continue; __reg_op(bitmap, pos, order, REG_OP_ALLOC); return pos; } return -ENOMEM; |
1da177e4c
|
1091 1092 1093 1094 |
} EXPORT_SYMBOL(bitmap_find_free_region); /** |
87e248025
|
1095 |
* bitmap_release_region - release allocated bitmap region |
3cf64b933
|
1096 1097 1098 |
* @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 |
1da177e4c
|
1099 |
* |
72fd4a35a
|
1100 |
* This is the complement to __bitmap_find_free_region() and releases |
1da177e4c
|
1101 |
* the found region (by clearing it in the bitmap). |
3cf64b933
|
1102 1103 |
* * No return value. |
1da177e4c
|
1104 |
*/ |
9279d3286
|
1105 |
void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) |
1da177e4c
|
1106 |
{ |
3cf64b933
|
1107 |
__reg_op(bitmap, pos, order, REG_OP_RELEASE); |
1da177e4c
|
1108 1109 |
} EXPORT_SYMBOL(bitmap_release_region); |
87e248025
|
1110 1111 |
/** * bitmap_allocate_region - allocate bitmap region |
3cf64b933
|
1112 1113 1114 |
* @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 |
87e248025
|
1115 1116 |
* * Allocate (set bits in) a specified region of a bitmap. |
3cf64b933
|
1117 |
* |
6e1907ffd
|
1118 |
* Return 0 on success, or %-EBUSY if specified region wasn't |
87e248025
|
1119 1120 |
* free (not all bits were zero). */ |
9279d3286
|
1121 |
int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) |
1da177e4c
|
1122 |
{ |
3cf64b933
|
1123 1124 |
if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) return -EBUSY; |
2ac521d33
|
1125 |
return __reg_op(bitmap, pos, order, REG_OP_ALLOC); |
1da177e4c
|
1126 1127 |
} EXPORT_SYMBOL(bitmap_allocate_region); |
ccbe329bc
|
1128 1129 1130 1131 1132 1133 1134 1135 1136 |
/** * 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. */ |
e8f242783
|
1137 |
#ifdef __BIG_ENDIAN |
9b6c2d2e2
|
1138 |
void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits) |
ccbe329bc
|
1139 |
{ |
9b6c2d2e2
|
1140 |
unsigned int i; |
ccbe329bc
|
1141 1142 1143 |
for (i = 0; i < nbits/BITS_PER_LONG; i++) { if (BITS_PER_LONG == 64) |
9b6c2d2e2
|
1144 |
dst[i] = cpu_to_le64(src[i]); |
ccbe329bc
|
1145 |
else |
9b6c2d2e2
|
1146 |
dst[i] = cpu_to_le32(src[i]); |
ccbe329bc
|
1147 1148 1149 |
} } EXPORT_SYMBOL(bitmap_copy_le); |
e8f242783
|
1150 |
#endif |
c724f1936
|
1151 |
|
c42b65e36
|
1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 |
unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags) { return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long), flags); } EXPORT_SYMBOL(bitmap_alloc); unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags) { return bitmap_alloc(nbits, flags | __GFP_ZERO); } EXPORT_SYMBOL(bitmap_zalloc); void bitmap_free(const unsigned long *bitmap) { kfree(bitmap); } EXPORT_SYMBOL(bitmap_free); |
c724f1936
|
1170 1171 1172 1173 1174 1175 1176 |
#if BITS_PER_LONG == 64 /** * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap * @bitmap: array of unsigned longs, the destination bitmap * @buf: array of u32 (in host byte order), the source bitmap * @nbits: number of bits in @bitmap */ |
ccf7a6d45
|
1177 |
void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits) |
c724f1936
|
1178 1179 |
{ unsigned int i, halfwords; |
c724f1936
|
1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 |
halfwords = DIV_ROUND_UP(nbits, 32); for (i = 0; i < halfwords; i++) { bitmap[i/2] = (unsigned long) buf[i]; if (++i < halfwords) bitmap[i/2] |= ((unsigned long) buf[i]) << 32; } /* Clear tail bits in last word beyond nbits. */ if (nbits % BITS_PER_LONG) bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits); } EXPORT_SYMBOL(bitmap_from_arr32); /** * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits * @buf: array of u32 (in host byte order), the dest bitmap * @bitmap: array of unsigned longs, the source bitmap * @nbits: number of bits in @bitmap */ void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits) { unsigned int i, halfwords; |
c724f1936
|
1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 |
halfwords = DIV_ROUND_UP(nbits, 32); for (i = 0; i < halfwords; i++) { buf[i] = (u32) (bitmap[i/2] & UINT_MAX); if (++i < halfwords) buf[i] = (u32) (bitmap[i/2] >> 32); } /* Clear tail bits in last element of array beyond nbits. */ if (nbits % BITS_PER_LONG) buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31)); } EXPORT_SYMBOL(bitmap_to_arr32); #endif |