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| author |   Ben Horgan <ben.horgan@arm.com> | 2025-07-09 10:38:08 +0100 |
|---|---|---|
| committer |   Yury Norov <yury.norov@gmail.com> | 2025-07-31 11:28:03 -0400 |
| commit | e2b02d382ae0cb90697e8529dfd3f93bf8c6905c (patch) | |
| tree | f5685a9bd7dfab3e03c1358d20091bbdc1ae9951 | |
| parent | test_bits: add tests for __GENMASK() and __GENMASK_ULL() (diff) | |
| download | wireguard-linux-e2b02d382ae0cb90697e8529dfd3f93bf8c6905c.tar.xz wireguard-linux-e2b02d382ae0cb90697e8529dfd3f93bf8c6905c.zip | |
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: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
| -rw-r--r-- | include/linux/bitfield.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h index 6d9a53db54b6..5355f8f806a9 100644 --- a/include/linux/bitfield.h +++ b/include/linux/bitfield.h @@ -189,14 +189,14 @@ 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, \ - 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); \ } \ @@ -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); \ } |