diff options
| -rw-r--r-- | include/linux/find.h | 25 | ||||
| -rw-r--r-- | lib/find_bit.c | 11 |
2 files changed, 36 insertions, 0 deletions
diff --git a/include/linux/find.h b/include/linux/find.h index 68685714bc18..5a2c267ea7f9 100644 --- a/include/linux/find.h +++ b/include/linux/find.h @@ -29,6 +29,8 @@ unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1, const unsign unsigned long n); extern unsigned long _find_first_and_bit(const unsigned long *addr1, const unsigned long *addr2, unsigned long size); +unsigned long _find_first_andnot_bit(const unsigned long *addr1, const unsigned long *addr2, + unsigned long size); unsigned long _find_first_and_and_bit(const unsigned long *addr1, const unsigned long *addr2, const unsigned long *addr3, unsigned long size); extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size); @@ -348,6 +350,29 @@ unsigned long find_first_and_bit(const unsigned long *addr1, #endif /** + * find_first_andnot_bit - find the first bit set in 1st memory region and unset in 2nd + * @addr1: The first address to base the search on + * @addr2: The second address to base the search on + * @size: The bitmap size in bits + * + * Returns the bit number for the first set bit + * If no bits are set, returns >= @size. + */ +static __always_inline +unsigned long find_first_andnot_bit(const unsigned long *addr1, + const unsigned long *addr2, + unsigned long size) +{ + if (small_const_nbits(size)) { + unsigned long val = *addr1 & (~*addr2) & GENMASK(size - 1, 0); + + return val ? __ffs(val) : size; + } + + return _find_first_andnot_bit(addr1, addr2, size); +} + +/** * find_first_and_and_bit - find the first set bit in 3 memory regions * @addr1: The first address to base the search on * @addr2: The second address to base the search on diff --git a/lib/find_bit.c b/lib/find_bit.c index 0836bb3d76c5..06b6342aa3ae 100644 --- a/lib/find_bit.c +++ b/lib/find_bit.c @@ -117,6 +117,17 @@ EXPORT_SYMBOL(_find_first_and_bit); #endif /* + * Find the first bit set in 1st memory region and unset in 2nd. + */ +unsigned long _find_first_andnot_bit(const unsigned long *addr1, + const unsigned long *addr2, + unsigned long size) +{ + return FIND_FIRST_BIT(addr1[idx] & ~addr2[idx], /* nop */, size); +} +EXPORT_SYMBOL(_find_first_andnot_bit); + +/* * Find the first set bit in three memory regions. */ unsigned long _find_first_and_and_bit(const unsigned long *addr1, |