diff options
Diffstat (limited to 'include/linux/overflow.h')
| -rw-r--r-- | include/linux/overflow.h | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 40b48e2133cb..659045046468 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -36,6 +36,12 @@ #define type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T))) #define type_min(T) ((T)((T)-type_max(T)-(T)1)) +/* + * Avoids triggering -Wtype-limits compilation warning, + * while using unsigned data types to check a < 0. + */ +#define is_non_negative(a) ((a) > 0 || (a) == 0) +#define is_negative(a) (!(is_non_negative(a))) #ifdef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW /* @@ -227,10 +233,10 @@ typeof(d) _d = d; \ u64 _a_full = _a; \ unsigned int _to_shift = \ - _s >= 0 && _s < 8 * sizeof(*d) ? _s : 0; \ + is_non_negative(_s) && _s < 8 * sizeof(*d) ? _s : 0; \ *_d = (_a_full << _to_shift); \ - (_to_shift != _s || *_d < 0 || _a < 0 || \ - (*_d >> _to_shift) != _a); \ + (_to_shift != _s || is_negative(*_d) || is_negative(_a) || \ + (*_d >> _to_shift) != _a); \ }) /** @@ -278,11 +284,15 @@ static inline __must_check size_t array3_size(size_t a, size_t b, size_t c) return bytes; } -static inline __must_check size_t __ab_c_size(size_t n, size_t size, size_t c) +/* + * Compute a*b+c, returning SIZE_MAX on overflow. Internal helper for + * struct_size() below. + */ +static inline __must_check size_t __ab_c_size(size_t a, size_t b, size_t c) { size_t bytes; - if (check_mul_overflow(n, size, &bytes)) + if (check_mul_overflow(a, b, &bytes)) return SIZE_MAX; if (check_add_overflow(bytes, c, &bytes)) return SIZE_MAX; |