#define _LGPL_SOURCE
void __attribute__((destructor)) urcu_qsbr_exit(void);
+static void urcu_call_rcu_exit(void);
/*
* rcu_gp_lock ensures mutual exclusion between threads calling
{
/* Read reader_gp before read futex */
cmm_smp_rmb();
- if (uatomic_read(&urcu_qsbr_gp.futex) != -1)
- return;
- while (futex_noasync(&urcu_qsbr_gp.futex, FUTEX_WAIT, -1,
- NULL, NULL, 0)) {
+ while (uatomic_read(&urcu_qsbr_gp.futex) == -1) {
+ if (!futex_noasync(&urcu_qsbr_gp.futex, FUTEX_WAIT, -1, NULL, NULL, 0)) {
+ /*
+ * Prior queued wakeups queued by unrelated code
+ * using the same address can cause futex wait to
+ * return 0 even through the futex value is still
+ * -1 (spurious wakeups). Check the value again
+ * in user-space to validate whether it really
+ * differs from -1.
+ */
+ continue;
+ }
switch (errno) {
- case EWOULDBLOCK:
+ case EAGAIN:
/* Value already changed. */
return;
case EINTR:
/* Retry if interrupted by signal. */
- break; /* Get out of switch. */
+ break; /* Get out of switch. Check again. */
default:
/* Unexpected error. */
urcu_die(errno);
* readers, and left running at exit.
* urcu_posix_assert(cds_list_empty(®istry));
*/
+ urcu_call_rcu_exit();
}
DEFINE_RCU_FLAVOR(rcu_flavor);
#include "urcu-call-rcu-impl.h"
#include "urcu-defer-impl.h"
+#include "urcu-poll-impl.h"