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bitmap: genericize percpu bitmap region iterators

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Bitmaps are fairly popular for their space efficiency, but we don't have
generic iterators available. Make percpu's bitmap region iterators
available to everyone.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Dennis Zhou 2019-12-13 16:22:10 -08:00 • committed by David Sterba
parent 147a097cf0
commit e837dfde15
2 changed files with 51 additions and 45 deletions
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35
include/linux/bitmap.h
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@ -456,6 +456,41 @@ static inline int bitmap_parse(const char *buf, unsigned int buflen,
return __bitmap_parse(buf, buflen, 0, maskp, nmaskbits);
}
static inline void bitmap_next_clear_region(unsigned long *bitmap,
unsigned int *rs, unsigned int *re,
unsigned int end)
{
*rs = find_next_zero_bit(bitmap, end, *rs);
*re = find_next_bit(bitmap, end, *rs + 1);
}
static inline void bitmap_next_set_region(unsigned long *bitmap,
unsigned int *rs, unsigned int *re,
unsigned int end)
{
*rs = find_next_bit(bitmap, end, *rs);
*re = find_next_zero_bit(bitmap, end, *rs + 1);
}
/*
* Bitmap region iterators. Iterates over the bitmap between [@start, @end).
* @rs and @re should be integer variables and will be set to start and end
* index of the current clear or set region.
*/
#define bitmap_for_each_clear_region(bitmap, rs, re, start, end) \
for ((rs) = (start), \
bitmap_next_clear_region((bitmap), &(rs), &(re), (end)); \
(rs) < (re); \
(rs) = (re) + 1, \
bitmap_next_clear_region((bitmap), &(rs), &(re), (end)))
#define bitmap_for_each_set_region(bitmap, rs, re, start, end) \
for ((rs) = (start), \
bitmap_next_set_region((bitmap), &(rs), &(re), (end)); \
(rs) < (re); \
(rs) = (re) + 1, \
bitmap_next_set_region((bitmap), &(rs), &(re), (end)))
/**
* BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
* @n: u64 value