diff options
Diffstat (limited to 'include/linux/cleanup.h')
| -rw-r--r-- | include/linux/cleanup.h | 58 |
1 files changed, 54 insertions, 4 deletions
diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h index 8d41b917c77d..dbc4162921e9 100644 --- a/include/linux/cleanup.h +++ b/include/linux/cleanup.h @@ -278,16 +278,21 @@ const volatile void * __must_check_fn(const volatile void *val) #define DEFINE_CLASS(_name, _type, _exit, _init, _init_args...) \ typedef _type class_##_name##_t; \ +typedef _type lock_##_name##_t; \ static __always_inline void class_##_name##_destructor(_type *p) \ + __no_context_analysis \ { _type _T = *p; _exit; } \ static __always_inline _type class_##_name##_constructor(_init_args) \ + __no_context_analysis \ { _type t = _init; return t; } #define EXTEND_CLASS(_name, ext, _init, _init_args...) \ +typedef lock_##_name##_t lock_##_name##ext##_t; \ typedef class_##_name##_t class_##_name##ext##_t; \ static __always_inline void class_##_name##ext##_destructor(class_##_name##_t *p) \ { class_##_name##_destructor(p); } \ static __always_inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ + __no_context_analysis \ { class_##_name##_t t = _init; return t; } #define CLASS(_name, var) \ @@ -474,35 +479,80 @@ _label: \ */ #define __DEFINE_UNLOCK_GUARD(_name, _type, _unlock, ...) \ +typedef _type lock_##_name##_t; \ typedef struct { \ _type *lock; \ __VA_ARGS__; \ } class_##_name##_t; \ \ static __always_inline void class_##_name##_destructor(class_##_name##_t *_T) \ + __no_context_analysis \ { \ if (!__GUARD_IS_ERR(_T->lock)) { _unlock; } \ } \ \ __DEFINE_GUARD_LOCK_PTR(_name, &_T->lock) -#define __DEFINE_LOCK_GUARD_1(_name, _type, _lock) \ +#define __DEFINE_LOCK_GUARD_1(_name, _type, ...) \ static __always_inline class_##_name##_t class_##_name##_constructor(_type *l) \ + __no_context_analysis \ { \ class_##_name##_t _t = { .lock = l }, *_T = &_t; \ - _lock; \ + __VA_ARGS__; \ return _t; \ } -#define __DEFINE_LOCK_GUARD_0(_name, _lock) \ +#define __DEFINE_LOCK_GUARD_0(_name, ...) \ static __always_inline class_##_name##_t class_##_name##_constructor(void) \ + __no_context_analysis \ { \ class_##_name##_t _t = { .lock = (void*)1 }, \ *_T __maybe_unused = &_t; \ - _lock; \ + __VA_ARGS__; \ return _t; \ } +#define DECLARE_LOCK_GUARD_0_ATTRS(_name, _lock, _unlock) \ +static inline class_##_name##_t class_##_name##_constructor(void) _lock;\ +static inline void class_##_name##_destructor(class_##_name##_t *_T) _unlock; + +/* + * To support Context Analysis, we need to allow the compiler to see the + * acquisition and release of the context lock. However, the "cleanup" helpers + * wrap the lock in a struct passed through separate helper functions, which + * hides the lock alias from the compiler (no inter-procedural analysis). + * + * To make it work, we introduce an explicit alias to the context lock instance + * that is "cleaned" up with a separate cleanup helper. This helper is a dummy + * function that does nothing at runtime, but has the "_unlock" attribute to + * tell the compiler what happens at the end of the scope. + * + * To generalize the pattern, the WITH_LOCK_GUARD_1_ATTRS() macro should be used + * to redefine the constructor, which then also creates the alias variable with + * the right "cleanup" attribute, *after* DECLARE_LOCK_GUARD_1_ATTRS() has been + * used. + * + * Example usage: + * + * DECLARE_LOCK_GUARD_1_ATTRS(mutex, __acquires(_T), __releases(*(struct mutex **)_T)) + * #define class_mutex_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(mutex, _T) + * + * Note: To support the for-loop based scoped helpers, the auxiliary variable + * must be a pointer to the "class" type because it is defined in the same + * statement as the guard variable. However, we initialize it with the lock + * pointer (despite the type mismatch, the compiler's alias analysis still works + * as expected). The "_unlock" attribute receives a pointer to the auxiliary + * variable (a double pointer to the class type), and must be cast and + * dereferenced appropriately. + */ +#define DECLARE_LOCK_GUARD_1_ATTRS(_name, _lock, _unlock) \ +static inline class_##_name##_t class_##_name##_constructor(lock_##_name##_t *_T) _lock;\ +static __always_inline void __class_##_name##_cleanup_ctx(class_##_name##_t **_T) \ + __no_context_analysis _unlock { } +#define WITH_LOCK_GUARD_1_ATTRS(_name, _T) \ + class_##_name##_constructor(_T), \ + *__UNIQUE_ID(unlock) __cleanup(__class_##_name##_cleanup_ctx) = (void *)(unsigned long)(_T) + #define DEFINE_LOCK_GUARD_1(_name, _type, _lock, _unlock, ...) \ __DEFINE_CLASS_IS_CONDITIONAL(_name, false); \ __DEFINE_UNLOCK_GUARD(_name, _type, _unlock, __VA_ARGS__) \ |