X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=src%2Fworkqueue.c;h=46b097273772dfaa1d29508b6995e4be48471527;hb=becacd5ac79ec6d8196d682798f1b5ad269737bc;hp=14957a0d3910aa83740d4e22b5420aa48658cf84;hpb=5bbe95bb510534d0a5bab8d7d205b32d6e4a57b2;p=urcu.git

diff --git a/src/workqueue.c b/src/workqueue.c
index 14957a0..46b0972 100644
--- a/src/workqueue.c
+++ b/src/workqueue.c
@@ -36,12 +36,12 @@
 #include <sched.h>
 
 #include "compat-getcpu.h"
-#include "urcu/wfcqueue.h"
-#include "urcu-pointer.h"
-#include "urcu/list.h"
-#include "urcu/futex.h"
-#include "urcu/tls-compat.h"
-#include "urcu/ref.h"
+#include <urcu/wfcqueue.h>
+#include <urcu/pointer.h>
+#include <urcu/list.h>
+#include <urcu/futex.h>
+#include <urcu/tls-compat.h>
+#include <urcu/ref.h>
 #include "urcu-die.h"
 
 #include "workqueue.h"
@@ -92,7 +92,7 @@ struct urcu_workqueue_completion_work {
  * Losing affinity can be caused by CPU hotunplug/hotplug, or by
  * cpuset(7).
  */
-#if HAVE_SCHED_SETAFFINITY
+#ifdef HAVE_SCHED_SETAFFINITY
 static int set_thread_cpu_affinity(struct urcu_workqueue *workqueue)
 {
 	cpu_set_t mask;
@@ -124,7 +124,7 @@ static int set_thread_cpu_affinity(struct urcu_workqueue *workqueue)
 	return ret;
 }
 #else
-static int set_thread_cpu_affinity(struct urcu_workqueue *workqueue)
+static int set_thread_cpu_affinity(struct urcu_workqueue *workqueue __attribute__((unused)))
 {
 	return 0;
 }
@@ -134,16 +134,25 @@ static void futex_wait(int32_t *futex)
 {
 	/* Read condition before read futex */
 	cmm_smp_mb();
-	if (uatomic_read(futex) != -1)
-		return;
-	while (futex_async(futex, FUTEX_WAIT, -1, NULL, NULL, 0)) {
+	while (uatomic_read(futex) == -1) {
+		if (!futex_async(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);