uatomic/x86: Remove redundant memory barriers

[urcu.git] / include / urcu / tls-compat.h

diff --git a/include/urcu/tls-compat.h b/include/urcu/tls-compat.h
index db22dde6758550cad1dbf329ef050c7916706ffd..1f3ef0fbbdb5bfe8f03d58e642ccdc1373e2f54c 100644 (file)
--- a/include/urcu/tls-compat.h
+++ b/include/urcu/tls-compat.h
@@ -1,26 +1,12 @@
+// SPDX-FileCopyrightText: 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
 #ifndef _URCU_TLS_COMPAT_H
 #define _URCU_TLS_COMPAT_H
 
 /*
- * urcu/tls-compat.h
- *
  * Userspace RCU library - Thread-Local Storage Compatibility Header
- *
- * Copyright 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <stdlib.h>
@@ -34,11 +20,15 @@ extern "C" {
 
 #ifdef CONFIG_RCU_TLS
 
-#if defined (__cplusplus) && __cplusplus >= 201103L
-# define URCU_TLS_STORAGE_CLASS        thread_local
-#elif defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
-# define URCU_TLS_STORAGE_CLASS        _Thread_local
-#elif defined (_MSC_VER)
+/*
+ * Default to '__thread' on all C and C++ compilers except MSVC. While C11 has
+ * '_Thread_local' and C++11 has 'thread_local', only '__thread' seems to have
+ * a compatible implementation when linking public extern symbols across
+ * language boundaries.
+ *
+ * For more details, see 'https://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html'.
+ */
+#if defined(_MSC_VER)
 # define URCU_TLS_STORAGE_CLASS        __declspec(thread)
 #else
 # define URCU_TLS_STORAGE_CLASS        __thread
@@ -112,6 +102,7 @@ struct urcu_tls {
        type *__tls_access_ ## name(void)                       \
        {                                                       \
                static struct urcu_tls __tls_ ## name = {       \
+                       .key = 0,                               \
                        .init_mutex = PTHREAD_MUTEX_INITIALIZER,\
                        .init_done = 0,                         \
                };                                              \
@@ -128,9 +119,9 @@ struct urcu_tls {
                        pthread_mutex_unlock(&__tls_ ## name.init_mutex); \
                }                                               \
                cmm_smp_rmb();  /* read init_done before getting key */ \
-               __tls_p = pthread_getspecific(__tls_ ## name.key); \
+               __tls_p = (__typeof__(type) *) pthread_getspecific(__tls_ ## name.key); \
                if (caa_unlikely(__tls_p == NULL)) {            \
-                       __tls_p = calloc(1, sizeof(type));      \
+                       __tls_p = (__typeof__(type) *) calloc(1, sizeof(type)); \
                        do_init                                 \
                        (void) pthread_setspecific(__tls_ ## name.key,  \
                                __tls_p);                       \