403 pipe_semaphore_init(pipe_semaphore *sema, int init_val)  in pipe_semaphore_init()  argument
405    pipe_mutex_init(sema->mutex);  in pipe_semaphore_init()
406    pipe_condvar_init(sema->cond);  in pipe_semaphore_init()
407    sema->counter = init_val;  in pipe_semaphore_init()
411 pipe_semaphore_destroy(pipe_semaphore *sema)  in pipe_semaphore_destroy()  argument
413    pipe_mutex_destroy(sema->mutex);  in pipe_semaphore_destroy()
414    pipe_condvar_destroy(sema->cond);  in pipe_semaphore_destroy()
419 pipe_semaphore_signal(pipe_semaphore *sema)  in pipe_semaphore_signal()  argument
421    pipe_mutex_lock(sema->mutex);  in pipe_semaphore_signal()
422    sema->counter++;  in pipe_semaphore_signal()
423    pipe_condvar_signal(sema->cond);  in pipe_semaphore_signal()
424    pipe_mutex_unlock(sema->mutex);  in pipe_semaphore_signal()
429 pipe_semaphore_wait(pipe_semaphore *sema)  in pipe_semaphore_wait()  argument
431    pipe_mutex_lock(sema->mutex);  in pipe_semaphore_wait()
432    while (sema->counter <= 0) {  in pipe_semaphore_wait()
433       pipe_condvar_wait(sema->cond, sema->mutex);  in pipe_semaphore_wait()
435    sema->counter--;  in pipe_semaphore_wait()
436    pipe_mutex_unlock(sema->mutex);  in pipe_semaphore_wait()