1#include "pthread_impl.h"
 2#include "syscall.h"
 3
 4static volatile int check_pi_result = -1;
 5
 6int pthread_mutexattr_setprotocol(pthread_mutexattr_t *a, int protocol)
 7{
 8	int r;
 9	switch (protocol) {
10	case PTHREAD_PRIO_NONE:
11		a->__attr &= ~8;
12		return 0;
13	case PTHREAD_PRIO_INHERIT:
14		r = check_pi_result;
15		if (r < 0) {
16			volatile int lk = 0;
17			r = -__syscall(SYS_futex, &lk, FUTEX_LOCK_PI, 0, 0);
18			a_store(&check_pi_result, r);
19		}
20		if (r) return r;
21		a->__attr |= 8;
22		return 0;
23	case PTHREAD_PRIO_PROTECT:
24		return ENOTSUP;
25	default:
26		return EINVAL;
27	}
28}