diff options
Diffstat (limited to 'include/linux/overflow.h')
| -rw-r--r-- | include/linux/overflow.h | 52 |
1 files changed, 44 insertions, 8 deletions
diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 736f633b2d5f..a5e95dbce220 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -36,12 +36,6 @@ #define __type_min(T) ((T)((T)-type_max(T)-(T)1)) #define type_min(t) __type_min(typeof(t)) -/* - * 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))) /* * Allows for effectively applying __must_check to a macro so we can have @@ -201,9 +195,9 @@ static inline bool __must_check __must_check_overflow(bool overflow) typeof(d) _d = d; \ unsigned long long _a_full = _a; \ unsigned int _to_shift = \ - is_non_negative(_s) && _s < 8 * sizeof(*d) ? _s : 0; \ + _s >= 0 && _s < 8 * sizeof(*d) ? _s : 0; \ *_d = (_a_full << _to_shift); \ - (_to_shift != _s || is_negative(*_d) || is_negative(_a) || \ + (_to_shift != _s || *_d < 0 || _a < 0 || \ (*_d >> _to_shift) != _a); \ })) @@ -552,4 +546,46 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) (__member_size((name)->array) / sizeof(*(name)->array) + \ __must_be_array((name)->array)) +/** + * typeof_flex_counter() - Return the type of the counter variable of a given + * flexible array member annotated by __counted_by(). + * @FAM: Instance of flexible array member within a given struct. + * + * Returns: "size_t" if no annotation exists. + */ +#define typeof_flex_counter(FAM) \ + typeof(_Generic(__flex_counter(FAM), \ + void *: (size_t)0, \ + default: *__flex_counter(FAM))) + +/** + * overflows_flex_counter_type() - Check if the counter associated with the + * given flexible array member can represent + * a value. + * @TYPE: Type of the struct that contains the @FAM. + * @FAM: Member name of the FAM within @TYPE. + * @COUNT: Value to check against the __counted_by annotated @FAM's counter. + * + * Returns: true if @COUNT can be represented in the @FAM's counter. When + * @FAM is not annotated with __counted_by(), always returns true. + */ +#define overflows_flex_counter_type(TYPE, FAM, COUNT) \ + (!overflows_type(COUNT, typeof_flex_counter(((TYPE *)NULL)->FAM))) + +/** + * __set_flex_counter() - Set the counter associated with the given flexible + * array member that has been annoated by __counted_by(). + * @FAM: Instance of flexible array member within a given struct. + * @COUNT: Value to store to the __counted_by annotated @FAM_PTR's counter. + * + * This is a no-op if no annotation exists. Count needs to be checked with + * overflows_flex_counter_type() before using this function. + */ +#define __set_flex_counter(FAM, COUNT) \ +({ \ + *_Generic(__flex_counter(FAM), \ + void *: &(size_t){ 0 }, \ + default: __flex_counter(FAM)) = (COUNT); \ +}) + #endif /* __LINUX_OVERFLOW_H */ |