ovs-atomic: New library for atomic operations.

This library should prove useful for the threading changes coming up.
The following commit introduces one (very simple) user.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Ethan Jackson <ethan@nicira.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/lib/ovs-atomic-pthreads.c b/lib/ovs-atomic-pthreads.c
new file mode 100644
index 00000000..a501b825
--- /dev/null
+++ b/lib/ovs-atomic-pthreads.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2013 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+
+#include "ovs-atomic.h"
+#include "ovs-thread.h"
+
+#if OVS_ATOMIC_PTHREADS_IMPL
+bool
+atomic_flag_test_and_set(volatile atomic_flag *flag_)
+{
+    atomic_flag *flag = CONST_CAST(atomic_flag *, flag_);
+    bool old_value;
+
+    xpthread_mutex_lock(&flag->mutex);
+    old_value = flag->b;
+    flag->b = true;
+    xpthread_mutex_unlock(&flag->mutex);
+
+    return old_value;
+}
+
+bool
+atomic_flag_test_and_set_explicit(volatile atomic_flag *flag,
+                                  memory_order order OVS_UNUSED)
+{
+    return atomic_flag_test_and_set(flag);
+}
+
+void
+atomic_flag_clear(volatile atomic_flag *flag_)
+{
+    atomic_flag *flag = CONST_CAST(atomic_flag *, flag_);
+
+    xpthread_mutex_lock(&flag->mutex);
+    flag->b = false;
+    xpthread_mutex_unlock(&flag->mutex);
+}
+
+void
+atomic_flag_clear_explicit(volatile atomic_flag *flag,
+                           memory_order order OVS_UNUSED)
+{
+    return atomic_flag_clear(flag);
+}
+
+#endif  /* OVS_ATOMIC_PTHREADS_IMPL */