bitfield.h: add FIELD_MAX() and field_max() (e31a5016) · Commits · 戴 / test

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>

include/linux/bitfield.h

+14 −0

Original line number	Diff line number	Diff line
		@@ -55,6 +55,19 @@
		(1ULL << __bf_shf(_mask))); \
		})

		/**
		* 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
		@@ -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) \
		{ \

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