diff options
Diffstat (limited to 'include/linux/semaphore.h')
| -rw-r--r-- | include/linux/semaphore.h | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/include/linux/semaphore.h b/include/linux/semaphore.h index 6694d0019a68..89706157e622 100644 --- a/include/linux/semaphore.h +++ b/include/linux/semaphore.h @@ -16,17 +16,35 @@ struct semaphore { raw_spinlock_t lock; unsigned int count; struct list_head wait_list; + +#ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER + unsigned long last_holder; +#endif }; +#ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER +#define __LAST_HOLDER_SEMAPHORE_INITIALIZER \ + , .last_holder = 0UL +#else +#define __LAST_HOLDER_SEMAPHORE_INITIALIZER +#endif + #define __SEMAPHORE_INITIALIZER(name, n) \ { \ .lock = __RAW_SPIN_LOCK_UNLOCKED((name).lock), \ .count = n, \ - .wait_list = LIST_HEAD_INIT((name).wait_list), \ + .wait_list = LIST_HEAD_INIT((name).wait_list) \ + __LAST_HOLDER_SEMAPHORE_INITIALIZER \ } -#define DEFINE_SEMAPHORE(name) \ - struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1) +/* + * Unlike mutexes, binary semaphores do not have an owner, so up() can + * be called in a different thread from the one which called down(). + * It is also safe to call down_trylock() and up() from interrupt + * context. + */ +#define DEFINE_SEMAPHORE(_name, _n) \ + struct semaphore _name = __SEMAPHORE_INITIALIZER(_name, _n) static inline void sema_init(struct semaphore *sem, int val) { @@ -41,5 +59,6 @@ extern int __must_check down_killable(struct semaphore *sem); extern int __must_check down_trylock(struct semaphore *sem); extern int __must_check down_timeout(struct semaphore *sem, long jiffies); extern void up(struct semaphore *sem); +extern unsigned long sem_last_holder(struct semaphore *sem); #endif /* __LINUX_SEMAPHORE_H */ |