bitmap: bitmap_count_one_with_offset

Count the number of 1s in a bitmap starting from an offset.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
CC: Dr. David Alan Gilbert <dgilbert@redhat.com>
CC: Juan Quintela <quintela@redhat.com>
CC: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1544516693-5395-3-git-send-email-wei.w.wang@intel.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Wei Wang 2018-12-11 16:24:48 +08:00 committed by Dr. David Alan Gilbert
parent e7c91368d2
commit 94960256ae
1 changed files with 13 additions and 0 deletions

View File

@ -232,6 +232,19 @@ static inline long bitmap_count_one(const unsigned long *bitmap, long nbits)
}
}
static inline long bitmap_count_one_with_offset(const unsigned long *bitmap,
long offset, long nbits)
{
long aligned_offset = QEMU_ALIGN_DOWN(offset, BITS_PER_LONG);
long redundant_bits = offset - aligned_offset;
long bits_to_count = nbits + redundant_bits;
const unsigned long *bitmap_start = bitmap +
aligned_offset / BITS_PER_LONG;
return bitmap_count_one(bitmap_start, bits_to_count) -
bitmap_count_one(bitmap_start, redundant_bits);
}
void bitmap_set(unsigned long *map, long i, long len);
void bitmap_set_atomic(unsigned long *map, long i, long len);
void bitmap_clear(unsigned long *map, long start, long nr);