diff options
| -rw-r--r-- | include/linux/semaphore.h | 6 | ||||
| -rw-r--r-- | kernel/semaphore.c | 22 |
2 files changed, 28 insertions, 0 deletions
diff --git a/include/linux/semaphore.h b/include/linux/semaphore.h index b3c691b089b2..88f2a28cc0f1 100644 --- a/include/linux/semaphore.h +++ b/include/linux/semaphore.h @@ -62,6 +62,12 @@ extern void down(struct semaphore *sem); extern int __must_check down_interruptible(struct semaphore *sem); /* + * As down_interruptible(), except the sleep may only be interrupted by + * signals which are fatal to this process. + */ +extern int __must_check down_killable(struct semaphore *sem); + +/* * As down(), except this function will not sleep. It will return 0 if it * acquired the semaphore and 1 if the semaphore was contended. This * function may be called from any context, including interrupt and softirq. diff --git a/kernel/semaphore.c b/kernel/semaphore.c index d5a72702f261..2da2aed950f3 100644 --- a/kernel/semaphore.c +++ b/kernel/semaphore.c @@ -34,6 +34,7 @@ static noinline void __down(struct semaphore *sem); static noinline int __down_interruptible(struct semaphore *sem); +static noinline int __down_killable(struct semaphore *sem); static noinline void __up(struct semaphore *sem); void down(struct semaphore *sem) @@ -61,6 +62,20 @@ int down_interruptible(struct semaphore *sem) } EXPORT_SYMBOL(down_interruptible); +int down_killable(struct semaphore *sem) +{ + unsigned long flags; + int result = 0; + + spin_lock_irqsave(&sem->lock, flags); + if (unlikely(sem->count-- <= 0)) + result = __down_killable(sem); + spin_unlock_irqrestore(&sem->lock, flags); + + return result; +} +EXPORT_SYMBOL(down_killable); + /** * down_trylock - try to acquire the semaphore, without waiting * @sem: the semaphore to be acquired @@ -143,6 +158,8 @@ static inline int __sched __down_common(struct semaphore *sem, long state) for (;;) { if (state == TASK_INTERRUPTIBLE && signal_pending(task)) goto interrupted; + if (state == TASK_KILLABLE && fatal_signal_pending(task)) + goto interrupted; __set_task_state(task, state); spin_unlock_irq(&sem->lock); schedule(); @@ -178,6 +195,11 @@ static noinline int __sched __down_interruptible(struct semaphore *sem) return __down_common(sem, TASK_INTERRUPTIBLE); } +static noinline int __sched __down_killable(struct semaphore *sem) +{ + return __down_common(sem, TASK_KILLABLE); +} + static noinline void __sched __up(struct semaphore *sem) { if (unlikely(list_empty(&sem->wait_list))) |