X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fcommon%2Ffutex.c;h=d0f95abc8b8175ebb4bf158bd7df364cad2f4bcd;hb=3afa94aeca5a0daae40fd7b6cc96b7e4c150c7d8;hp=adfe66b1c29feb3295949253f315819c8d110d92;hpb=50c8f4840cc0cf140c760159c8705592d6b434ea;p=lttng-tools.git

diff --git a/src/common/futex.c b/src/common/futex.c
index adfe66b1c..d0f95abc8 100644
--- a/src/common/futex.c
+++ b/src/common/futex.c
@@ -1,29 +1,18 @@
 /*
- * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
- *                       Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <limits.h>
-#include <sys/syscall.h>
 #include <unistd.h>
 #include <urcu.h>
 #include <urcu/futex.h>
 
-#include <common/error.h>
+#include <common/common.h>
 
 #include "futex.h"
 
@@ -53,8 +42,11 @@ void futex_wait_update(int32_t *futex, int active)
 {
 	if (active) {
 		uatomic_set(futex, 1);
-		futex_async(futex, FUTEX_WAKE,
-				INT_MAX, NULL, NULL, 0);
+		if (futex_async(futex, FUTEX_WAKE,
+				INT_MAX, NULL, NULL, 0) < 0) {
+			PERROR("futex_async");
+			abort();
+		}
 	} else {
 		uatomic_set(futex, 0);
 	}
@@ -80,10 +72,23 @@ void futex_nto1_wait(int32_t *futex)
 {
 	cmm_smp_mb();
 
-	if (uatomic_read(futex) == -1) {
-		futex_async(futex, FUTEX_WAIT, -1, NULL, NULL, 0);
+	if (uatomic_read(futex) != -1)
+		goto end;
+	while (futex_async(futex, FUTEX_WAIT, -1, NULL, NULL, 0)) {
+		switch (errno) {
+		case EWOULDBLOCK:
+			/* Value already changed. */
+			goto end;
+		case EINTR:
+			/* Retry if interrupted by signal. */
+			break;	/* Get out of switch. */
+		default:
+			/* Unexpected error. */
+			PERROR("futex_async");
+			abort();
+		}
 	}
-
+end:
 	DBG("Futex n to 1 wait done");
 }
 
@@ -92,10 +97,13 @@ void futex_nto1_wait(int32_t *futex)
  */
 void futex_nto1_wake(int32_t *futex)
 {
-	if (caa_unlikely(uatomic_read(futex) == -1)) {
-		uatomic_set(futex, 0);
-		futex_async(futex, FUTEX_WAKE, 1, NULL, NULL, 0);
+	if (caa_unlikely(uatomic_read(futex) != -1))
+		goto end;
+	uatomic_set(futex, 0);
+	if (futex_async(futex, FUTEX_WAKE, 1, NULL, NULL, 0) < 0) {
+		PERROR("futex_async");
+		abort();
 	}
-
+end:
 	DBG("Futex n to 1 wake done");
 }