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| author | Yu-Chien Peter Lin <[email protected]> | 2026-03-11 20:51:15 +0800 |
|---|---|---|
| committer | Anup Patel <[email protected]> | 2026-04-08 17:58:05 +0530 |
| commit | ff7d245b86daa36aa36147022fa583e79ffe25cc (patch) | |
| tree | a713aeb93bbfccce15a2074f5be3f3d92874da29 | |
| parent | 0b041e58c0787f76325da5081e41a13bf304d328 (diff) | |
include: sbi_bitmap: add bitmap_empty() function
Add bitmap_empty() to check if bitmap has no bits set.
Unlike bitmap_weight() which calls sbi_popcount() on every word,
bitmap_empty() uses simple non-zero comparisons with early exit.
Signed-off-by: Yu-Chien Peter Lin <[email protected]>
Reviewed-by: Anup Patel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Anup Patel <[email protected]>
| -rw-r--r-- | include/sbi/sbi_bitmap.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/sbi/sbi_bitmap.h b/include/sbi/sbi_bitmap.h index 596bcc7d..80d3fe3b 100644 --- a/include/sbi/sbi_bitmap.h +++ b/include/sbi/sbi_bitmap.h @@ -143,4 +143,20 @@ static inline int bitmap_weight(const unsigned long *src, int nbits) return res; } +static inline bool bitmap_empty(const unsigned long *src, int nbits) +{ + if (nbits == 0) + return true; + + if (small_const_nbits(nbits)) + return !(*src & BITMAP_LAST_WORD_MASK(nbits)); + else { + size_t i, len = BITS_TO_LONGS(nbits); + for (i = 0; i < len - 1; i++) + if (src[i]) + return false; + return !(src[len - 1] & BITMAP_LAST_WORD_MASK(nbits)); + } +} + #endif |