diff options
Diffstat (limited to 'lib/bitmap.c')
-rw-r--r-- | lib/bitmap.c | 80 |
1 files changed, 32 insertions, 48 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index 324ea9eab8c1..ad161a6c82db 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -744,10 +744,10 @@ 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 < @bits) - * @bits: number of valid bit positions in @buf + * @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 @bits) to the + * 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. * @@ -759,56 +759,40 @@ EXPORT_SYMBOL(bitmap_parselist_user); * * The bit positions 0 through @bits are valid positions in @buf. */ -static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits) +static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits) { - int i, ord; - - if (pos < 0 || pos >= bits || !test_bit(pos, buf)) + if (pos >= nbits || !test_bit(pos, buf)) return -1; - i = find_first_bit(buf, bits); - ord = 0; - while (i < pos) { - i = find_next_bit(buf, bits, i + 1); - ord++; - } - BUG_ON(i != pos); - - return ord; + 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) - * @bits: number of valid bit positions in @buf + * @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), else - * results are undefined. + * 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 return undefined values. When @ord value 3 + * 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 @bits are valid positions in @buf. + * The bit positions 0 through @nbits-1 are valid positions in @buf. */ -int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits) +unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits) { - int pos = 0; - - if (ord >= 0 && ord < bits) { - int i; + unsigned int pos; - for (i = find_first_bit(buf, bits); - i < bits && ord > 0; - i = find_next_bit(buf, bits, i + 1)) - ord--; - if (i < bits && ord == 0) - pos = i; - } + for (pos = find_first_bit(buf, nbits); + pos < nbits && ord; + pos = find_next_bit(buf, nbits, pos + 1)) + ord--; return pos; } @@ -819,7 +803,7 @@ int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits) * @src: subset to be remapped * @old: defines domain of map * @new: defines range of map - * @bits: number of bits in each of these bitmaps + * @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 @@ -847,22 +831,22 @@ int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits) */ void bitmap_remap(unsigned long *dst, const unsigned long *src, const unsigned long *old, const unsigned long *new, - int bits) + unsigned int nbits) { - int oldbit, w; + unsigned int oldbit, w; if (dst == src) /* following doesn't handle inplace remaps */ return; - bitmap_zero(dst, bits); + bitmap_zero(dst, nbits); - w = bitmap_weight(new, bits); - for_each_set_bit(oldbit, src, bits) { - int n = bitmap_pos_to_ord(old, oldbit, bits); + 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, bits), dst); + set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst); } } EXPORT_SYMBOL(bitmap_remap); @@ -1006,9 +990,9 @@ EXPORT_SYMBOL(bitmap_bitremap); * 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, int bits) + const unsigned long *relmap, unsigned int bits) { - int n, m; /* same meaning as in above comment */ + unsigned int n, m; /* same meaning as in above comment */ if (dst == orig) /* following doesn't handle inplace mappings */ return; @@ -1039,22 +1023,22 @@ EXPORT_SYMBOL(bitmap_onto); * @dst: resulting smaller bitmap * @orig: original larger bitmap * @sz: specified size - * @bits: number of bits in each of these bitmaps + * @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, - int sz, int bits) + unsigned int sz, unsigned int nbits) { - int oldbit; + unsigned int oldbit; if (dst == orig) /* following doesn't handle inplace mappings */ return; - bitmap_zero(dst, bits); + bitmap_zero(dst, nbits); - for_each_set_bit(oldbit, orig, bits) + for_each_set_bit(oldbit, orig, nbits) set_bit(oldbit % sz, dst); } EXPORT_SYMBOL(bitmap_fold); |