+static void call_rcu_wait(struct call_rcu_data *crdp)
+{
+ /* Read call_rcu list before read futex */
+ cmm_smp_mb();
+ if (uatomic_read(&crdp->futex) != -1)
+ return;
+ while (futex_async(&crdp->futex, FUTEX_WAIT, -1,
+ NULL, NULL, 0)) {
+ switch (errno) {
+ case EWOULDBLOCK:
+ /* Value already changed. */
+ return;
+ case EINTR:
+ /* Retry if interrupted by signal. */
+ break; /* Get out of switch. */
+ default:
+ /* Unexpected error. */
+ urcu_die(errno);
+ }
+ }
+}
+
+static void call_rcu_wake_up(struct call_rcu_data *crdp)
+{
+ /* Write to call_rcu list before reading/writing futex */
+ cmm_smp_mb();
+ if (caa_unlikely(uatomic_read(&crdp->futex) == -1)) {
+ uatomic_set(&crdp->futex, 0);
+ if (futex_async(&crdp->futex, FUTEX_WAKE, 1,
+ NULL, NULL, 0) < 0)
+ urcu_die(errno);
+ }
+}
+