diff options
| author | Alex Elder <elder@linaro.org> | 2020-03-12 11:44:27 -0500 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-03-12 15:48:37 -0700 |
| commit | e31a50162feb352147d3fc87b9e036703c8f2636 (patch) | |
| tree | efa42592a94ddb1b3cb2b62a8a1e6a903c914cbb | |
| parent | 82a9822b26770b3965790f6a2340f0341a9bc102 (diff) | |
bitfield.h: add FIELD_MAX() and field_max()
Define FIELD_MAX(), which supplies the maximum value that can be
represented by a field value. Define field_max() as well, to go
along with the lower-case forms of the field mask functions.
Signed-off-by: Alex Elder <elder@linaro.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/bitfield.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h index 4bbb5f1c8b5b..48ea093ff04c 100644 --- a/include/linux/bitfield.h +++ b/include/linux/bitfield.h @@ -56,6 +56,19 @@ }) /** + * FIELD_MAX() - produce the maximum value representable by a field + * @_mask: shifted mask defining the field's length and position + * + * FIELD_MAX() returns the maximum value that can be held in the field + * specified by @_mask. + */ +#define FIELD_MAX(_mask) \ + ({ \ + __BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_MAX: "); \ + (typeof(_mask))((_mask) >> __bf_shf(_mask)); \ + }) + +/** * FIELD_FIT() - check if value fits in the field * @_mask: shifted mask defining the field's length and position * @_val: value to test against the field @@ -110,6 +123,7 @@ static __always_inline u64 field_mask(u64 field) { return field / field_multiplier(field); } +#define field_max(field) ((typeof(field))field_mask(field)) #define ____MAKE_OP(type,base,to,from) \ static __always_inline __##type type##_encode_bits(base v, base field) \ { \ |