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Diffstat (limited to 'lib/bitmap.c')
| -rw-r--r-- | lib/bitmap.c | 1197 |
1 files changed, 1197 insertions, 0 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c new file mode 100644 index 000000000..c4ca9ceb0 --- /dev/null +++ b/lib/bitmap.c @@ -0,0 +1,1197 @@ +/* + * 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/mm.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/uaccess.h> + +#include <asm/page.h> + +/** + * DOC: bitmap introduction + * + * 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; +} +EXPORT_SYMBOL(__bitmap_equal); + +void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits) +{ + unsigned int k, lim = BITS_TO_LONGS(bits); + for (k = 0; k < lim; ++k) + dst[k] = ~src[k]; +} +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)); +} +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)); +} +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; +} +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]; +} +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]; +} +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; +} +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; +} +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; +} +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; +} +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; + } +} +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; + } +} +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; +} +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; +} +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); + +} +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, 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'. + */ +int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, + int nmaskbits) +{ + ptrdiff_t len = PAGE_SIZE - offset_in_page(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; +} +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. + * Optionally each range can be postfixed to denote that only parts of it + * should be set. The range will divided to groups of specific size. + * From each group will be used only defined amount of bits. + * Syntax: range:used_size/group_size + * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769 + * + * Returns: 0 on success, -errno on invalid input strings. Error values: + * + * - ``-EINVAL``: second number in range smaller than first + * - ``-EINVAL``: invalid character in string + * - ``-ERANGE``: bit number specified too large for mask + */ +static int __bitmap_parselist(const char *buf, unsigned int buflen, + int is_user, unsigned long *maskp, + int nmaskbits) +{ + unsigned int a, b, old_a, old_b; + unsigned int group_size, used_size, off; + int c, old_c, totaldigits, ndigits; + const char __user __force *ubuf = (const char __user __force *)buf; + int at_start, in_range, in_partial_range; + + totaldigits = c = 0; + old_a = old_b = 0; + group_size = used_size = 0; + bitmap_zero(maskp, nmaskbits); + do { + at_start = 1; + in_range = 0; + in_partial_range = 0; + a = b = 0; + ndigits = totaldigits; + + /* Get the next cpu# or a range of cpu#'s */ + while (buflen) { + old_c = c; + if (is_user) { + if (__get_user(c, ubuf++)) + return -EFAULT; + } else + c = *buf++; + buflen--; + if (isspace(c)) + continue; + + /* A '\0' or a ',' signal the end of a cpu# or range */ + if (c == '\0' || c == ',') + break; + /* + * whitespaces between digits are not allowed, + * but it's ok if whitespaces are on head or tail. + * when old_c is whilespace, + * if totaldigits == ndigits, whitespace is on head. + * if whitespace is on tail, it should not run here. + * as c was ',' or '\0', + * the last code line has broken the current loop. + */ + if ((totaldigits != ndigits) && isspace(old_c)) + return -EINVAL; + + if (c == '/') { + used_size = a; + at_start = 1; + in_range = 0; + a = b = 0; + continue; + } + + if (c == ':') { + old_a = a; + old_b = b; + at_start = 1; + in_range = 0; + in_partial_range = 1; + a = b = 0; + continue; + } + + if (c == '-') { + if (at_start || in_range) + return -EINVAL; + b = 0; + in_range = 1; + at_start = 1; + continue; + } + + if (!isdigit(c)) + return -EINVAL; + + b = b * 10 + (c - '0'); + if (!in_range) + a = b; + at_start = 0; + totaldigits++; + } + if (ndigits == totaldigits) + continue; + if (in_partial_range) { + group_size = a; + a = old_a; + b = old_b; + old_a = old_b = 0; + } else { + used_size = group_size = b - a + 1; + } + /* if no digit is after '-', it's wrong*/ + if (at_start && in_range) + return -EINVAL; + if (!(a <= b) || group_size == 0 || !(used_size <= group_size)) + return -EINVAL; + if (b >= nmaskbits) + return -ERANGE; + while (a <= b) { + off = min(b - a + 1, used_size); + bitmap_set(maskp, a, off); + a += group_size; + } + } while (buflen && c == ','); + return 0; +} + +int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) +{ + char *nl = strchrnul(bp, '\n'); + int len = nl - bp; + + return __bitmap_parselist(bp, len, 0, maskp, nmaskbits); +} +EXPORT_SYMBOL(bitmap_parselist); + + +/** + * bitmap_parselist_user() + * + * @ubuf: pointer to user buffer containing string. + * @ulen: buffer size in bytes. If string is smaller than this + * then it must be terminated with a \0. + * @maskp: pointer to bitmap array that will contain result. + * @nmaskbits: size of bitmap, in bits. + * + * Wrapper for bitmap_parselist(), providing it with user buffer. + * + * We cannot have this as an inline function in bitmap.h because it needs + * linux/uaccess.h to get the access_ok() declaration and this causes + * cyclic dependencies. + */ +int bitmap_parselist_user(const char __user *ubuf, + unsigned int ulen, unsigned long *maskp, + int nmaskbits) +{ + if (!access_ok(VERIFY_READ, ubuf, ulen)) + return -EFAULT; + return __bitmap_parselist((const char __force *)ubuf, + ulen, 1, maskp, nmaskbits); +} +EXPORT_SYMBOL(bitmap_parselist_user); + + +/** + * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap + * @buf: pointer to a bitmap + * @pos: a bit position in @buf (0 <= @pos < @nbits) + * @nbits: number of valid bit positions in @buf + * + * Map the bit at position @pos in @buf (of length @nbits) to the + * ordinal of which set bit it is. If it is not set or if @pos + * is not a valid bit position, map to -1. + * + * If for example, just bits 4 through 7 are set in @buf, then @pos + * values 4 through 7 will get mapped to 0 through 3, respectively, + * and other @pos values will get mapped to -1. When @pos value 7 + * gets mapped to (returns) @ord value 3 in this example, that means + * that bit 7 is the 3rd (starting with 0th) set bit in @buf. + * + * The bit positions 0 through @bits are valid positions in @buf. + */ +static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits) +{ + if (pos >= nbits || !test_bit(pos, buf)) + return -1; + + return __bitmap_weight(buf, pos); +} + +/** + * bitmap_ord_to_pos - find position of n-th set bit in bitmap + * @buf: pointer to bitmap + * @ord: ordinal bit position (n-th set bit, n >= 0) + * @nbits: number of valid bit positions in @buf + * + * Map the ordinal offset of bit @ord in @buf to its position in @buf. + * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord + * >= weight(buf), returns @nbits. + * + * If for example, just bits 4 through 7 are set in @buf, then @ord + * values 0 through 3 will get mapped to 4 through 7, respectively, + * and all other @ord values returns @nbits. When @ord value 3 + * gets mapped to (returns) @pos value 7 in this example, that means + * that the 3rd set bit (starting with 0th) is at position 7 in @buf. + * + * The bit positions 0 through @nbits-1 are valid positions in @buf. + */ +unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits) +{ + unsigned int pos; + + for (pos = find_first_bit(buf, nbits); + pos < nbits && ord; + pos = find_next_bit(buf, nbits, pos + 1)) + ord--; + + return pos; +} + +/** + * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap + * @dst: remapped result + * @src: subset to be remapped + * @old: defines domain of map + * @new: defines range of map + * @nbits: number of bits in each of these bitmaps + * + * Let @old and @new define a mapping of bit positions, such that + * whatever position is held by the n-th set bit in @old is mapped + * to the n-th set bit in @new. In the more general case, allowing + * for the possibility that the weight 'w' of @new is less than the + * weight of @old, map the position of the n-th set bit in @old to + * the position of the m-th set bit in @new, where m == n % w. + * + * If either of the @old and @new bitmaps are empty, or if @src and + * @dst point to the same location, then this routine copies @src + * to @dst. + * + * The positions of unset bits in @old are mapped to themselves + * (the identify map). + * + * Apply the above specified mapping to @src, placing the result in + * @dst, clearing any bits previously set in @dst. + * + * For example, lets say that @old has bits 4 through 7 set, and + * @new has bits 12 through 15 set. This defines the mapping of bit + * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other + * bit positions unchanged. So if say @src comes into this routine + * with bits 1, 5 and 7 set, then @dst should leave with bits 1, + * 13 and 15 set. + */ +void bitmap_remap(unsigned long *dst, const unsigned long *src, + const unsigned long *old, const unsigned long *new, + unsigned int nbits) +{ + unsigned int oldbit, w; + + if (dst == src) /* following doesn't handle inplace remaps */ + return; + bitmap_zero(dst, nbits); + + w = bitmap_weight(new, nbits); + for_each_set_bit(oldbit, src, nbits) { + int n = bitmap_pos_to_ord(old, oldbit, nbits); + + if (n < 0 || w == 0) + set_bit(oldbit, dst); /* identity map */ + else + set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst); + } +} +EXPORT_SYMBOL(bitmap_remap); + +/** + * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit + * @oldbit: bit position to be mapped + * @old: defines domain of map + * @new: defines range of map + * @bits: number of bits in each of these bitmaps + * + * Let @old and @new define a mapping of bit positions, such that + * whatever position is held by the n-th set bit in @old is mapped + * to the n-th set bit in @new. In the more general case, allowing + * for the possibility that the weight 'w' of @new is less than the + * weight of @old, map the position of the n-th set bit in @old to + * the position of the m-th set bit in @new, where m == n % w. + * + * The positions of unset bits in @old are mapped to themselves + * (the identify map). + * + * Apply the above specified mapping to bit position @oldbit, returning + * the new bit position. + * + * For example, lets say that @old has bits 4 through 7 set, and + * @new has bits 12 through 15 set. This defines the mapping of bit + * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other + * bit positions unchanged. So if say @oldbit is 5, then this routine + * returns 13. + */ +int bitmap_bitremap(int oldbit, const unsigned long *old, + const unsigned long *new, int bits) +{ + int w = bitmap_weight(new, bits); + int n = bitmap_pos_to_ord(old, oldbit, bits); + if (n < 0 || w == 0) + return oldbit; + else + return bitmap_ord_to_pos(new, n % w, bits); +} +EXPORT_SYMBOL(bitmap_bitremap); + +/** + * bitmap_onto - translate one bitmap relative to another + * @dst: resulting translated bitmap + * @orig: original untranslated bitmap + * @relmap: bitmap relative to which translated + * @bits: number of bits in each of these bitmaps + * + * Set the n-th bit of @dst iff there exists some m such that the + * n-th bit of @relmap is set, the m-th bit of @orig is set, and + * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. + * (If you understood the previous sentence the first time your + * read it, you're overqualified for your current job.) + * + * In other words, @orig is mapped onto (surjectively) @dst, + * using the map { <n, m> | the n-th bit of @relmap is the + * m-th set bit of @relmap }. + * + * Any set bits in @orig above bit number W, where W is the + * weight of (number of set bits in) @relmap are mapped nowhere. + * In particular, if for all bits m set in @orig, m >= W, then + * @dst will end up empty. In situations where the possibility + * of such an empty result is not desired, one way to avoid it is + * to use the bitmap_fold() operator, below, to first fold the + * @orig bitmap over itself so that all its set bits x are in the + * range 0 <= x < W. The bitmap_fold() operator does this by + * setting the bit (m % W) in @dst, for each bit (m) set in @orig. + * + * Example [1] for bitmap_onto(): + * Let's say @relmap has bits 30-39 set, and @orig has bits + * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, + * @dst will have bits 31, 33, 35, 37 and 39 set. + * + * When bit 0 is set in @orig, it means turn on the bit in + * @dst corresponding to whatever is the first bit (if any) + * that is turned on in @relmap. Since bit 0 was off in the + * above example, we leave off that bit (bit 30) in @dst. + * + * When bit 1 is set in @orig (as in the above example), it + * means turn on the bit in @dst corresponding to whatever + * is the second bit that is turned on in @relmap. The second + * bit in @relmap that was turned on in the above example was + * bit 31, so we turned on bit 31 in @dst. + * + * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, + * because they were the 4th, 6th, 8th and 10th set bits + * set in @relmap, and the 4th, 6th, 8th and 10th bits of + * @orig (i.e. bits 3, 5, 7 and 9) were also set. + * + * When bit 11 is set in @orig, it means turn on the bit in + * @dst corresponding to whatever is the twelfth bit that is + * turned on in @relmap. In the above example, there were + * only ten bits turned on in @relmap (30..39), so that bit + * 11 was set in @orig had no affect on @dst. + * + * Example [2] for bitmap_fold() + bitmap_onto(): + * Let's say @relmap has these ten bits set:: + * + * 40 41 42 43 45 48 53 61 74 95 + * + * (for the curious, that's 40 plus the first ten terms of the + * Fibonacci sequence.) + * + * Further lets say we use the following code, invoking + * bitmap_fold() then bitmap_onto, as suggested above to + * avoid the possibility of an empty @dst result:: + * + * unsigned long *tmp; // a temporary bitmap's bits + * + * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); + * bitmap_onto(dst, tmp, relmap, bits); + * + * Then this table shows what various values of @dst would be, for + * various @orig's. I list the zero-based positions of each set bit. + * The tmp column shows the intermediate result, as computed by + * using bitmap_fold() to fold the @orig bitmap modulo ten + * (the weight of @relmap): + * + * =============== ============== ================= + * @orig tmp @dst + * 0 0 40 + * 1 1 41 + * 9 9 95 + * 10 0 40 [#f1]_ + * 1 3 5 7 1 3 5 7 41 43 48 61 + * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 + * 0 9 18 27 0 9 8 7 40 61 74 95 + * 0 10 20 30 0 40 + * 0 11 22 33 0 1 2 3 40 41 42 43 + * 0 12 24 36 0 2 4 6 40 42 45 53 + * 78 102 211 1 2 8 41 42 74 [#f1]_ + * =============== ============== ================= + * + * .. [#f1] + * + * For these marked lines, if we hadn't first done bitmap_fold() + * into tmp, then the @dst result would have been empty. + * + * If either of @orig or @relmap is empty (no set bits), then @dst + * will be returned empty. + * + * If (as explained above) the only set bits in @orig are in positions + * m where m >= W, (where W is the weight of @relmap) then @dst will + * once again be returned empty. + * + * All bits in @dst not set by the above rule are cleared. + */ +void bitmap_onto(unsigned long *dst, const unsigned long *orig, + const unsigned long *relmap, unsigned int bits) +{ + unsigned int n, m; /* same meaning as in above comment */ + + if (dst == orig) /* following doesn't handle inplace mappings */ + return; + bitmap_zero(dst, bits); + + /* + * The following code is a more efficient, but less + * obvious, equivalent to the loop: + * for (m = 0; m < bitmap_weight(relmap, bits); m++) { + * n = bitmap_ord_to_pos(orig, m, bits); + * if (test_bit(m, orig)) + * set_bit(n, dst); + * } + */ + + m = 0; + for_each_set_bit(n, relmap, bits) { + /* m == bitmap_pos_to_ord(relmap, n, bits) */ + if (test_bit(m, orig)) + set_bit(n, dst); + m++; + } +} +EXPORT_SYMBOL(bitmap_onto); + +/** + * bitmap_fold - fold larger bitmap into smaller, modulo specified size + * @dst: resulting smaller bitmap + * @orig: original larger bitmap + * @sz: specified size + * @nbits: number of bits in each of these bitmaps + * + * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. + * Clear all other bits in @dst. See further the comment and + * Example [2] for bitmap_onto() for why and how to use this. + */ +void bitmap_fold(unsigned long *dst, const unsigned long *orig, + unsigned int sz, unsigned int nbits) +{ + unsigned int oldbit; + + if (dst == orig) /* following doesn't handle inplace mappings */ + return; + bitmap_zero(dst, nbits); + + for_each_set_bit(oldbit, orig, nbits) + set_bit(oldbit % sz, dst); +} +EXPORT_SYMBOL(bitmap_fold); + +/* + * Common code for bitmap_*_region() routines. + * bitmap: array of unsigned longs corresponding to the bitmap + * pos: the beginning of the region + * order: region size (log base 2 of number of bits) + * reg_op: operation(s) to perform on that region of bitmap + * + * Can set, verify and/or release a region of bits in a bitmap, + * depending on which combination of REG_OP_* flag bits is set. + * + * A region of a bitmap is a sequence of bits in the bitmap, of + * some size '1 << order' (a power of two), aligned to that same + * '1 << order' power of two. + * + * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits). + * Returns 0 in all other cases and reg_ops. + */ + +enum { + REG_OP_ISFREE, /* true if region is all zero bits */ + REG_OP_ALLOC, /* set all bits in region */ + REG_OP_RELEASE, /* clear all bits in region */ +}; + +static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op) +{ + int nbits_reg; /* number of bits in region */ + int index; /* index first long of region in bitmap */ + int offset; /* bit offset region in bitmap[index] */ + int nlongs_reg; /* num longs spanned by region in bitmap */ + int nbitsinlong; /* num bits of region in each spanned long */ + unsigned long mask; /* bitmask for one long of region */ + int i; /* scans bitmap by longs */ + int ret = 0; /* return value */ + + /* + * Either nlongs_reg == 1 (for small orders that fit in one long) + * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) + */ + nbits_reg = 1 << order; + index = pos / BITS_PER_LONG; + offset = pos - (index * BITS_PER_LONG); + nlongs_reg = BITS_TO_LONGS(nbits_reg); + nbitsinlong = min(nbits_reg, BITS_PER_LONG); + + /* + * Can't do "mask = (1UL << nbitsinlong) - 1", as that + * overflows if nbitsinlong == BITS_PER_LONG. + */ + mask = (1UL << (nbitsinlong - 1)); + mask += mask - 1; + mask <<= offset; + + switch (reg_op) { + case REG_OP_ISFREE: + for (i = 0; i < nlongs_reg; i++) { + if (bitmap[index + i] & mask) + goto done; + } + ret = 1; /* all bits in region free (zero) */ + break; + + case REG_OP_ALLOC: + for (i = 0; i < nlongs_reg; i++) + bitmap[index + i] |= mask; + break; + + case REG_OP_RELEASE: + for (i = 0; i < nlongs_reg; i++) + bitmap[index + i] &= ~mask; + break; + } +done: + return ret; +} + +/** + * bitmap_find_free_region - find a contiguous aligned mem region + * @bitmap: array of unsigned longs corresponding to the bitmap + * @bits: number of bits in the bitmap + * @order: region size (log base 2 of number of bits) to find + * + * Find a region of free (zero) bits in a @bitmap of @bits bits and + * allocate them (set them to one). Only consider regions of length + * a power (@order) of two, aligned to that power of two, which + * makes the search algorithm much faster. + * + * Return the bit offset in bitmap of the allocated region, + * or -errno on failure. + */ +int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order) +{ + unsigned int pos, end; /* scans bitmap by regions of size order */ + + for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) { + if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) + continue; + __reg_op(bitmap, pos, order, REG_OP_ALLOC); + return pos; + } + return -ENOMEM; +} +EXPORT_SYMBOL(bitmap_find_free_region); + +/** + * bitmap_release_region - release allocated bitmap region + * @bitmap: array of unsigned longs corresponding to the bitmap + * @pos: beginning of bit region to release + * @order: region size (log base 2 of number of bits) to release + * + * This is the complement to __bitmap_find_free_region() and releases + * the found region (by clearing it in the bitmap). + * + * No return value. + */ +void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) +{ + __reg_op(bitmap, pos, order, REG_OP_RELEASE); +} +EXPORT_SYMBOL(bitmap_release_region); + +/** + * bitmap_allocate_region - allocate bitmap region + * @bitmap: array of unsigned longs corresponding to the bitmap + * @pos: beginning of bit region to allocate + * @order: region size (log base 2 of number of bits) to allocate + * + * Allocate (set bits in) a specified region of a bitmap. + * + * Return 0 on success, or %-EBUSY if specified region wasn't + * free (not all bits were zero). + */ +int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) +{ + if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) + return -EBUSY; + return __reg_op(bitmap, pos, order, REG_OP_ALLOC); +} +EXPORT_SYMBOL(bitmap_allocate_region); + +/** + * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order. + * @dst: destination buffer + * @src: bitmap to copy + * @nbits: number of bits in the bitmap + * + * Require nbits % BITS_PER_LONG == 0. + */ +#ifdef __BIG_ENDIAN +void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits) +{ + unsigned int i; + + for (i = 0; i < nbits/BITS_PER_LONG; i++) { + if (BITS_PER_LONG == 64) + dst[i] = cpu_to_le64(src[i]); + else + dst[i] = cpu_to_le32(src[i]); + } +} +EXPORT_SYMBOL(bitmap_copy_le); +#endif + +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); + +#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 + */ +void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits) +{ + unsigned int i, halfwords; + + 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; + + 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 |