[PATCH 2/2] bitfield: Ensure the return value of type##_replace_bits() is checked

Ben Horgan ben.horgan at arm.com
Thu Jul 3 06:57:29 PDT 2025


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.

Signed-off-by: Ben Horgan <ben.horgan at arm.com>
---
 include/linux/bitfield.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index 6d9a53db54b6..39333b80d22b 100644
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -195,8 +195,8 @@ static __always_inline __##type type##_encode_bits(base v, base field)	\
 		__field_overflow();					\
 	return to((v & field_mask(field)) * field_multiplier(field));	\
 }									\
-static __always_inline __##type type##_replace_bits(__##type old,	\
-					base val, base field)		\
+static __always_inline __##type __must_check type##_replace_bits(__##type old,	\
+							base val, base field)	\
 {									\
 	return (old & ~to(field)) | type##_encode_bits(val, field);	\
 }									\
-- 
2.43.0




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