Commit e2b02d38 authored by Ben Horgan's avatar Ben Horgan Committed by Yury Norov
Browse files

bitfield: Ensure the return values of helper functions are checked 



As type##_replace_bits() has no side effects it is only useful if its
return value is checked. Add __must_check to enforce this usage. To have
the bits replaced in-place typep##_replace_bits() can be used instead.

Although, type_##_get_bits() and type_##_encode_bits() are harder to misuse
they are still only useful if the return value is checked. For
consistency, also add __must_check to these.

Signed-off-by: default avatarBen Horgan <ben.horgan@arm.com>
Signed-off-by: default avatarYury Norov (NVIDIA) <yury.norov@gmail.com>
parent dcb23e18

include/linux/bitfield.h

+4 −4
Original line number Diff line number Diff line
@@ -189,13 +189,13 @@ static __always_inline u64 field_mask(u64 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)	\

static __always_inline __##type __must_check type##_encode_bits(base v, base field)	\

{									\

	if (__builtin_constant_p(v) && (v & ~field_mask(field)))	\

		__field_overflow();					\

	return to((v & field_mask(field)) * field_multiplier(field));	\

}									\

static __always_inline __##type type##_replace_bits(__##type old,	\

static __always_inline __##type __must_check type##_replace_bits(__##type old,	\

							base val, base field)	\

{									\

	return (old & ~to(field)) | type##_encode_bits(val, field);	\
@@ -205,7 +205,7 @@ static __always_inline void type##p_replace_bits(__##type *p, \ 
{									\

	*p = (*p & ~to(field)) | type##_encode_bits(val, field);	\

}									\

static __always_inline base type##_get_bits(__##type v, base field)	\

static __always_inline base __must_check type##_get_bits(__##type v, base field)	\

{									\

	return (from(v) & field)/field_multiplier(field);		\

}