diff options
Diffstat (limited to 'include/linux/cleanup.h')
| -rw-r--r-- | include/linux/cleanup.h | 52 |
1 files changed, 42 insertions, 10 deletions
diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h index 518bd1fd86fb..0cc66f8d28e7 100644 --- a/include/linux/cleanup.h +++ b/include/linux/cleanup.h @@ -285,14 +285,20 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ * similar to scoped_guard(), except it does fail when the lock * acquire fails. * + * Only for conditional locks. */ +#define __DEFINE_CLASS_IS_CONDITIONAL(_name, _is_cond) \ +static __maybe_unused const bool class_##_name##_is_conditional = _is_cond + #define DEFINE_GUARD(_name, _type, _lock, _unlock) \ + __DEFINE_CLASS_IS_CONDITIONAL(_name, false); \ DEFINE_CLASS(_name, _type, if (_T) { _unlock; }, ({ _lock; _T; }), _type _T); \ static inline void * class_##_name##_lock_ptr(class_##_name##_t *_T) \ { return (void *)(__force unsigned long)*_T; } #define DEFINE_GUARD_COND(_name, _ext, _condlock) \ + __DEFINE_CLASS_IS_CONDITIONAL(_name##_ext, true); \ EXTEND_CLASS(_name, _ext, \ ({ void *_t = _T; if (_T && !(_condlock)) _t = NULL; _t; }), \ class_##_name##_t _T) \ @@ -303,17 +309,40 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ CLASS(_name, __UNIQUE_ID(guard)) #define __guard_ptr(_name) class_##_name##_lock_ptr +#define __is_cond_ptr(_name) class_##_name##_is_conditional -#define scoped_guard(_name, args...) \ - for (CLASS(_name, scope)(args), \ - *done = NULL; __guard_ptr(_name)(&scope) && !done; done = (void *)1) - -#define scoped_cond_guard(_name, _fail, args...) \ - for (CLASS(_name, scope)(args), \ - *done = NULL; !done; done = (void *)1) \ - if (!__guard_ptr(_name)(&scope)) _fail; \ - else - +/* + * Helper macro for scoped_guard(). + * + * Note that the "!__is_cond_ptr(_name)" part of the condition ensures that + * compiler would be sure that for the unconditional locks the body of the + * loop (caller-provided code glued to the else clause) could not be skipped. + * It is needed because the other part - "__guard_ptr(_name)(&scope)" - is too + * hard to deduce (even if could be proven true for unconditional locks). + */ +#define __scoped_guard(_name, _label, args...) \ + for (CLASS(_name, scope)(args); \ + __guard_ptr(_name)(&scope) || !__is_cond_ptr(_name); \ + ({ goto _label; })) \ + if (0) { \ +_label: \ + break; \ + } else + +#define scoped_guard(_name, args...) \ + __scoped_guard(_name, __UNIQUE_ID(label), args) + +#define __scoped_cond_guard(_name, _fail, _label, args...) \ + for (CLASS(_name, scope)(args); true; ({ goto _label; })) \ + if (!__guard_ptr(_name)(&scope)) { \ + BUILD_BUG_ON(!__is_cond_ptr(_name)); \ + _fail; \ +_label: \ + break; \ + } else + +#define scoped_cond_guard(_name, _fail, args...) \ + __scoped_cond_guard(_name, _fail, __UNIQUE_ID(label), args) /* * Additional helper macros for generating lock guards with types, either for * locks that don't have a native type (eg. RCU, preempt) or those that need a @@ -369,14 +398,17 @@ static inline class_##_name##_t class_##_name##_constructor(void) \ } #define DEFINE_LOCK_GUARD_1(_name, _type, _lock, _unlock, ...) \ +__DEFINE_CLASS_IS_CONDITIONAL(_name, false); \ __DEFINE_UNLOCK_GUARD(_name, _type, _unlock, __VA_ARGS__) \ __DEFINE_LOCK_GUARD_1(_name, _type, _lock) #define DEFINE_LOCK_GUARD_0(_name, _lock, _unlock, ...) \ +__DEFINE_CLASS_IS_CONDITIONAL(_name, false); \ __DEFINE_UNLOCK_GUARD(_name, void, _unlock, __VA_ARGS__) \ __DEFINE_LOCK_GUARD_0(_name, _lock) #define DEFINE_LOCK_GUARD_1_COND(_name, _ext, _condlock) \ + __DEFINE_CLASS_IS_CONDITIONAL(_name##_ext, true); \ EXTEND_CLASS(_name, _ext, \ ({ class_##_name##_t _t = { .lock = l }, *_T = &_t;\ if (_T->lock && !(_condlock)) _T->lock = NULL; \ |