218 pipe_semaphore_init(pipe_semaphore *sema, int init_val)  in pipe_semaphore_init()  argument
220    pipe_mutex_init(sema->mutex);  in pipe_semaphore_init()
221    pipe_condvar_init(sema->cond);  in pipe_semaphore_init()
222    sema->counter = init_val;  in pipe_semaphore_init()
226 pipe_semaphore_destroy(pipe_semaphore *sema)  in pipe_semaphore_destroy()  argument
228    pipe_mutex_destroy(sema->mutex);  in pipe_semaphore_destroy()
229    pipe_condvar_destroy(sema->cond);  in pipe_semaphore_destroy()
234 pipe_semaphore_signal(pipe_semaphore *sema)  in pipe_semaphore_signal()  argument
236    pipe_mutex_lock(sema->mutex);  in pipe_semaphore_signal()
237    sema->counter++;  in pipe_semaphore_signal()
238    pipe_condvar_signal(sema->cond);  in pipe_semaphore_signal()
239    pipe_mutex_unlock(sema->mutex);  in pipe_semaphore_signal()
244 pipe_semaphore_wait(pipe_semaphore *sema)  in pipe_semaphore_wait()  argument
246    pipe_mutex_lock(sema->mutex);  in pipe_semaphore_wait()
247    while (sema->counter <= 0) {  in pipe_semaphore_wait()
248       pipe_condvar_wait(sema->cond, sema->mutex);  in pipe_semaphore_wait()
250    sema->counter--;  in pipe_semaphore_wait()
251    pipe_mutex_unlock(sema->mutex);  in pipe_semaphore_wait()