Add common util to set thread name

[lttng-tools.git] / src / common / futex.c

diff --git a/src/common/futex.c b/src/common/futex.c
index 3c18f75fc8be6067f64d2a8fa5c97f54ca130dbc..332289924ab9ac3e1d88e54df78417175afa7238 100644 (file)
--- 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"
 
@@ -49,13 +38,16 @@
  * futex() call. If active, we set the value and wake everyone else we indicate
  * that we are gone (cleanup() case).
  */
-__attribute__((visibility("hidden")))
+LTTNG_HIDDEN
 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);
        }
@@ -66,7 +58,7 @@ void futex_wait_update(int32_t *futex, int active)
 /*
  * Prepare futex.
  */
-__attribute__((visibility("hidden")))
+LTTNG_HIDDEN
 void futex_nto1_prepare(int32_t *futex)
 {
        uatomic_set(futex, -1);
@@ -78,28 +70,44 @@ void futex_nto1_prepare(int32_t *futex)
 /*
  * Wait futex.
  */
-__attribute__((visibility("hidden")))
+LTTNG_HIDDEN
 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");
 }
 
 /*
  * Wake 1 futex.
  */
-__attribute__((visibility("hidden")))
+LTTNG_HIDDEN
 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");
 }