diff options
author | Valentin Schneider <vschneid@redhat.com> | 2022-10-03 16:34:17 +0100 |
---|---|---|
committer | Yury Norov <yury.norov@gmail.com> | 2022-10-06 05:57:36 -0700 |
commit | 90d482908eedd56f01a707325aa541cf9c40f936 (patch) | |
tree | 26cec02bff42dd83de558ba1b7579185726554b0 /include/linux/find.h | |
parent | 78e5a3399421ad79fc024e6d78e2deb7809d26af (diff) |
lib/find_bit: Introduce find_next_andnot_bit()
In preparation of introducing for_each_cpu_andnot(), add a variant of
find_next_bit() that negate the bits in @addr2 when ANDing them with the
bits in @addr1.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Diffstat (limited to 'include/linux/find.h')
-rw-r--r-- | include/linux/find.h | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/include/linux/find.h b/include/linux/find.h index 0cdfab9734a6..2235af19e7e1 100644 --- a/include/linux/find.h +++ b/include/linux/find.h @@ -12,6 +12,8 @@ unsigned long _find_next_bit(const unsigned long *addr1, unsigned long nbits, unsigned long start); unsigned long _find_next_and_bit(const unsigned long *addr1, const unsigned long *addr2, unsigned long nbits, unsigned long start); +unsigned long _find_next_andnot_bit(const unsigned long *addr1, const unsigned long *addr2, + unsigned long nbits, unsigned long start); unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits, unsigned long start); extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size); @@ -91,6 +93,37 @@ unsigned long find_next_and_bit(const unsigned long *addr1, } #endif +#ifndef find_next_andnot_bit +/** + * find_next_andnot_bit - find the next set bit in *addr1 excluding all the bits + * in *addr2 + * @addr1: The first address to base the search on + * @addr2: The second address to base the search on + * @size: The bitmap size in bits + * @offset: The bitnumber to start searching at + * + * Returns the bit number for the next set bit + * If no bits are set, returns @size. + */ +static inline +unsigned long find_next_andnot_bit(const unsigned long *addr1, + const unsigned long *addr2, unsigned long size, + unsigned long offset) +{ + if (small_const_nbits(size)) { + unsigned long val; + + if (unlikely(offset >= size)) + return size; + + val = *addr1 & ~*addr2 & GENMASK(size - 1, offset); + return val ? __ffs(val) : size; + } + + return _find_next_andnot_bit(addr1, addr2, size, offset); +} +#endif + #ifndef find_next_zero_bit /** * find_next_zero_bit - find the next cleared bit in a memory region |