From e03e20b7f618a7044e9e4208087051dabc13a164 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Kijewski?= <rene.kijewski@fu-berlin.de>
Date: Fri, 18 Jul 2014 13:44:29 +0200
Subject: [PATCH] core: simplify mutex initializer

---
 core/include/mutex.h | 20 ++++++++++++++------
 core/include/queue.h |  6 ++++++
 core/mutex.c         |  9 ---------
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/core/include/mutex.h b/core/include/mutex.h
index 0cdff269d3..ba138a8415 100644
--- a/core/include/mutex.h
+++ b/core/include/mutex.h
@@ -44,14 +44,22 @@ typedef struct mutex_t {
 } mutex_t;
 
 /**
- * @brief Initializes a mutex object.
- *
- * @param[out] mutex    pre-allocated mutex structure, must not be NULL.
- *
- * @return  Always returns 1, always succeeds.
+ * @brief Static initializer for mutex_t.
+ * @details This initializer is preferrable to mutex_init().
  */
-int mutex_init(mutex_t *mutex);
+#define MUTEX_INIT { 0, QUEUE_NODE_INIT }
 
+/**
+ * @brief Initializes a mutex object.
+ * @details For intialization of variables use MUTEX_INIT instead.
+ *          Only use the function call for dynamically allocated mutexes.
+ * @param[out] mutex    pre-allocated mutex structure, must not be NULL.
+ */
+static inline void mutex_init(mutex_t *mutex)
+{
+    mutex_t empty_mutex = MUTEX_INIT;
+    *mutex = empty_mutex;
+}
 
 /**
  * @brief Tries to get a mutex, non-blocking.
diff --git a/core/include/queue.h b/core/include/queue.h
index a0e6aadfcc..8d9416f056 100644
--- a/core/include/queue.h
+++ b/core/include/queue.h
@@ -20,6 +20,7 @@
 #ifndef __QUEUE_H
 #define __QUEUE_H
 
+#include <stddef.h>
 #include <stdint.h>
 #include <inttypes.h>
 
@@ -41,6 +42,11 @@ typedef struct queue_node_t {
     uint32_t priority;          /**< queue node priority */
 } queue_node_t;
 
+/**
+ * @brief Static initializer for queue_node_t.
+ */
+#define QUEUE_NODE_INIT { NULL, 0, 0 }
+
 /**
  * @brief attach `new_obj` to the tail of the queue (identified
  * `root`)
diff --git a/core/mutex.c b/core/mutex.c
index 180b3416bf..41fdcee818 100644
--- a/core/mutex.c
+++ b/core/mutex.c
@@ -35,15 +35,6 @@
 
 static void mutex_wait(struct mutex_t *mutex);
 
-void mutex_init(struct mutex_t *mutex)
-{
-    mutex->val = 0;
-
-    mutex->queue.priority = 0;
-    mutex->queue.data = 0;
-    mutex->queue.next = NULL;
-}
-
 int mutex_trylock(struct mutex_t *mutex)
 {
     DEBUG("%s: trylocking to get mutex. val: %u\n", sched_active_thread->name, mutex->val);