cregit-Linux how code gets into the kernel

Release 4.8 lib/bitmap.c

Directory: lib
/*
 * lib/bitmap.c
 * Helper functions for bitmap.h.
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */
#include <linux/export.h>
#include <linux/thread_info.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/uaccess.h>

#include <asm/page.h>

/*
 * 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.
 *
 * These operations actually hold to a slightly stronger rule:
 * if you don't input any bitmaps to these ops that have some
 * unused bits set, then they won't output any set unused bits
 * in output bitmaps.
 *
 * 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.
 */


int __bitmap_equal(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { unsigned int k, lim = bits/BITS_PER_LONG; 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; }

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andrew mortonandrew morton8897.78%375.00%
rasmus villemoesrasmus villemoes22.22%125.00%
Total90100.00%4100.00%

EXPORT_SYMBOL(__bitmap_equal);
void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits) { unsigned int k, lim = bits/BITS_PER_LONG; for (k = 0; k < lim; ++k) dst[k] = ~src[k]; if (bits % BITS_PER_LONG) dst[k] = ~src[k]; }

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andrew mortonandrew morton6997.18%480.00%
rasmus villemoesrasmus villemoes22.82%120.00%
Total71100.00%5100.00%

EXPORT_SYMBOL(__bitmap_complement); /** * __bitmap_shift_right - logical right shift of the bits in a bitmap * @dst : destination bitmap * @src : source bitmap * @shift : shift by this many bits * @nbits : bitmap size, in bits * * 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. */
void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, unsigned shift, unsigned nbits) { unsigned k, lim = BITS_TO_LONGS(nbits); unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; unsigned long mask = BITMAP_LAST_WORD_MASK(nbits); 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]; if (off + k + 1 == lim - 1) upper &= mask; upper <<= (BITS_PER_LONG - rem); } lower = src[off + k]; if (off + k == lim - 1) lower &= mask; lower >>= rem; dst[k] = lower | upper; } if (off) memset(&dst[lim - off], 0, off*sizeof(unsigned long)); }

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andrew mortonandrew morton16585.05%450.00%
rasmus villemoesrasmus villemoes2211.34%337.50%
jan karajan kara73.61%112.50%
Total194100.00%8100.00%

EXPORT_SYMBOL(__bitmap_shift_right); /** * __bitmap_shift_left - logical left shift of the bits in a bitmap * @dst : destination bitmap * @src : source bitmap * @shift : shift by this many bits * @nbits : bitmap size, in bits * * 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. */
void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, unsigned int shift, unsigned int nbits) { int k; unsigned int lim = BITS_TO_LONGS(nbits); unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; 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) lower = src[k - 1] >> (BITS_PER_LONG - rem); else lower = 0; upper = src[k] << rem; dst[k + off] = lower | upper; } if (off) memset(dst, 0, off*sizeof(unsigned long)); }

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andrew mortonandrew morton11882.52%457.14%
rasmus villemoesrasmus villemoes1711.89%228.57%
jan karajan kara85.59%114.29%
Total143100.00%7100.00%

EXPORT_SYMBOL(__bitmap_shift_left);
int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { unsigned int k; unsigned int lim = bits/BITS_PER_LONG; unsigned long result = 0; for (k = 0; k < lim; k++) result |= (dst[k] = bitmap1[k] & bitmap2[k]); if (bits % BITS_PER_LONG) result |= (dst[k] = bitmap1[k] & bitmap2[k] & BITMAP_LAST_WORD_MASK(bits)); return result != 0; }

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andrew mortonandrew morton5852.25%240.00%
rasmus villemoesrasmus villemoes3733.33%240.00%
linus torvaldslinus torvalds1614.41%120.00%
Total111100.00%5100.00%

EXPORT_SYMBOL(__bitmap_and);
void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { unsigned int k; unsigned int nr = BITS_TO_LONGS(bits); for (k = 0; k < nr; k++) dst[k] = bitmap1[k] | bitmap2[k]; }

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andrew mortonandrew morton6495.52%266.67%
rasmus villemoesrasmus villemoes34.48%133.33%
Total67100.00%3100.00%

EXPORT_SYMBOL(__bitmap_or);
void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { unsigned int k; unsigned int nr = BITS_TO_LONGS(bits); for (k = 0; k < nr; k++) dst[k] = bitmap1[k] ^ bitmap2[k]; }

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andrew mortonandrew morton6495.52%266.67%
rasmus villemoesrasmus villemoes34.48%133.33%
Total67100.00%3100.00%

EXPORT_SYMBOL(__bitmap_xor);
int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { unsigned int k; unsigned int lim = bits/BITS_PER_LONG; unsigned long result = 0; for (k = 0; k < lim; k++) result |= (dst[k] = bitmap1[k] & ~bitmap2[k]); if (bits % BITS_PER_LONG) result |= (dst[k] = bitmap1[k] & ~bitmap2[k] & BITMAP_LAST_WORD_MASK(bits)); return result != 0; }

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PersonTokensPropCommitsCommitProp
andrew mortonandrew morton5952.21%240.00%
rasmus villemoesrasmus villemoes3833.63%240.00%
linus torvaldslinus torvalds1614.16%120.00%
Total113100.00%5100.00%

EXPORT_SYMBOL(__bitmap_andnot);
int __bitmap_intersects(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { unsigned int k, lim = bits/BITS_PER_LONG; 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; }

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andrew mortonandrew morton8897.78%266.67%
rasmus villemoesrasmus villemoes22.22%133.33%
Total90100.00%3100.00%

EXPORT_SYMBOL(__bitmap_intersects);
int __bitmap_subset(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { unsigned int k, lim = bits/BITS_PER_LONG; 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; }

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andrew mortonandrew morton9097.83%266.67%
rasmus villemoesrasmus villemoes22.17%133.33%
Total92100.00%3100.00%

EXPORT_SYMBOL(__bitmap_subset);
int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) { unsigned int k, lim = bits/BITS_PER_LONG; int w = 0; for (k = 0; k < lim; k++) w += hweight_long(bitmap[k]); if (bits % BITS_PER_LONG) w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); return w; }

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andrew mortonandrew morton6888.31%250.00%
rasmus villemoesrasmus villemoes79.09%125.00%
akinobu mitaakinobu mita22.60%125.00%
Total77100.00%4100.00%

EXPORT_SYMBOL(__bitmap_weight);
void bitmap_set(unsigned long *map, unsigned int start, int len) { unsigned long *p = map + BIT_WORD(start); const unsigned int size = start + len; int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); while (len - bits_to_set >= 0) { *p |= mask_to_set; len -= bits_to_set; bits_to_set = BITS_PER_LONG; mask_to_set = ~0UL; p++; } if (len) { mask_to_set &= BITMAP_LAST_WORD_MASK(size); *p |= mask_to_set; } }

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akinobu mitaakinobu mita10093.46%150.00%
rasmus villemoesrasmus villemoes76.54%150.00%
Total107100.00%2100.00%

EXPORT_SYMBOL(bitmap_set);
void bitmap_clear(unsigned long *map, unsigned int start, int len) { unsigned long *p = map + BIT_WORD(start); const unsigned int size = start + len; int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); while (len - bits_to_clear >= 0) { *p &= ~mask_to_clear; len -= bits_to_clear; bits_to_clear = BITS_PER_LONG; mask_to_clear = ~0UL; p++; } if (len) { mask_to_clear &= BITMAP_LAST_WORD_MASK(size); *p &= ~mask_to_clear; } }

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akinobu mitaakinobu mita10293.58%150.00%
rasmus villemoesrasmus villemoes76.42%150.00%
Total109100.00%2100.00%

EXPORT_SYMBOL(bitmap_clear); /** * bitmap_find_next_zero_area_off - find a contiguous aligned zero area * @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 * @align_offset: Alignment offset for zero area. * * The @align_mask should be one less than a power of 2; the effect is that * the bit offset of all zero areas this function finds plus @align_offset * is multiple of that power of 2. */
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) { unsigned long index, end, i; again: index = find_next_zero_bit(map, size, start); /* Align allocation */ index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset; 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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akinobu mitaakinobu mita10391.96%150.00%
michal nazarewiczmichal nazarewicz98.04%150.00%
Total112100.00%2100.00%

EXPORT_SYMBOL(bitmap_find_next_zero_area_off); /* * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers, * second version by Paul Jackson, third by Joe Korty. */ #define CHUNKSZ 32 #define nbits_to_hold_value(val) fls(val) #define BASEDEC 10 /* fancier cpuset lists input in decimal */ /** * __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 * then it must be terminated with a \0. * @is_user: location of buffer, 0 indicates kernel space * @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 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value * then leading 0-bits are prepended. %-EINVAL is returned for illegal * characters and for grouping errors such as "1,,5", ",44", "," and "". * Leading and trailing whitespace accepted, but not embedded whitespace. */
int __bitmap_parse(const char *buf, unsigned int buflen, int is_user, unsigned long *maskp, int nmaskbits) { int c, old_c, totaldigits, ndigits, nchunks, nbits; u32 chunk; const char __user __force *ubuf = (const char __user __force *)buf; bitmap_zero(maskp, nmaskbits); nchunks = nbits = totaldigits = c = 0; do { chunk = 0; ndigits = totaldigits; /* Get the next chunk of the bitmap */ while (buflen) { old_c = c; if (is_user) { if (__get_user(c, ubuf++)) return -EFAULT; } else c = *buf++; buflen--; if (isspace(c)) continue; /* * If the last character was a space and the current * character isn't '\0', we've got embedded whitespace. * This is a no-no, so throw an error. */ if (totaldigits && c && isspace(old_c)) return -EINVAL; /* A '\0' or a ',' signal the end of the chunk */ if (c == '\0' || c == ',') break; if (!isxdigit(c)) return -EINVAL; /* * Make sure there are at least 4 free bits in 'chunk'. * If not, this hexdigit will overflow 'chunk', so * throw an error. */ if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1)) return -EOVERFLOW; chunk = (chunk << 4) | hex_to_bin(c); totaldigits++; } if (ndigits == totaldigits) return -EINVAL; if (nchunks == 0 && chunk == 0) continue; __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); *maskp |= chunk; nchunks++; nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ; if (nbits > nmaskbits) return -EOVERFLOW; } while (buflen && c == ','); return 0; }

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andrew mortonandrew morton24784.88%450.00%
reinette chatrereinette chatre3110.65%112.50%
h hartley sweetenh hartley sweeten82.75%112.50%
pan xinhuipan xinhui41.37%112.50%
andy shevchenkoandy shevchenko10.34%112.50%
Total291100.00%8100.00%

EXPORT_SYMBOL(__bitmap_parse); /** * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap * * @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) { if (!access_ok(VERIFY_READ, ubuf, ulen)) return -EFAULT; return __bitmap_parse((const char __force *)ubuf, ulen, 1, maskp, nmaskbits); }

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reinette chatrereinette chatre5898.31%150.00%
h hartley sweetenh hartley sweeten11.69%150.00%
Total59100.00%2100.00%

EXPORT_SYMBOL(bitmap_parse_user); /** * 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. * * It is assumed that @buf is a pointer into a PAGE_SIZE area and that * sufficient storage remains at @buf to accommodate the * bitmap_print_to_pagebuf() output. */
int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, int nmaskbits) { ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf; int n = 0; if (len > 1) n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) : scnprintf(buf, len, "%*pb\n", nmaskbits, maskp); return n; }

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sudeep hollasudeep holla7592.59%266.67%
tejun heotejun heo67.41%133.33%
Total81100.00%3100.00%

EXPORT_SYMBOL(bitmap_print_to_pagebuf); /** * __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. * * 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 a, b; int c, old_c, totaldigits, ndigits; const char __user __force *ubuf = (const char __user __force *)buf; int at_start, in_range; totaldigits = c = 0; bitmap_zero(maskp, nmaskbits); do { at_start = 1; in_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 == '-') { 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 no digit is after '-', it's wrong*/ if (at_start && in_range) return -EINVAL; if (!(a <= b)) return -EINVAL; if (b >= nmaskbits) return -ERANGE; while (a <= b) { set_bit(a, maskp); a++; } } while (buflen && c == ','); return 0; }

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mike travismike travis15047.47%116.67%
paul jacksonpaul jackson10934.49%116.67%
pan xinhuipan xinhui4514.24%233.33%
h hartley sweetenh hartley sweeten82.53%116.67%
chris metcalfchris metcalf41.27%116.67%
Total316100.00%6100.00%


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); }

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mike travismike travis4080.00%133.33%
paul jacksonpaul jackson714.00%133.33%
rasmus villemoesrasmus villemoes36.00%133.33%
Total50100.00%3100.00%

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); }

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mike travismike travis5898.31%150.00%
h hartley sweetenh hartley sweeten11.69%150.00%
Total59100.00%2100.00%

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); }

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paul jacksonpaul jackson4086.96%266.67%
rasmus villemoesrasmus villemoes613.04%133.33%
Total46100.00%3100.00%

/** * 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; }

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paul jacksonpaul jackson4880.00%150.00%
rasmus villemoesrasmus villemoes1220.00%150.00%
Total60100.00%2100.00%

/** * 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); } }

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PersonTokensPropCommitsCommitProp
paul jacksonpaul jackson10890.76%250.00%
rasmus villemoesrasmus villemoes86.72%125.00%
akinobu mitaakinobu mita32.52%125.00%
Total119100.00%4100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
paul jacksonpaul jackson71100.00%2100.00%
Total71100.00%2100.00%

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 (*) * 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 (*) * * (*) 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