Function umtx_pi_ref

freebsd/kern/kern_umtx.c:1725–1731

* Add reference count for a PI mutex. */

 * Add reference count for a PI mutex.
 */
static void
umtx_pi_ref(struct umtx_pi *pi)
{

	UMTXQ_LOCKED_ASSERT(umtxq_getchain(&pi->pi_key));
	pi->pi_refcount++;
}

/*
 * Decrease reference count for a PI mutex, if the counter