Merge pull request #1440 from Kijewski/issue-1436

core: simplify mutex signatures

core/hwtimer.c

@@ -122,13 +122,12 @@ void hwtimer_wait(unsigned long ticks)
 {
     DEBUG("hwtimer_wait ticks=%lu\n", ticks);
 
-    mutex_t mutex;
-
     if (ticks <= 6 || inISR()) {
         hwtimer_spin(ticks);
         return;
     }
-    mutex_init(&mutex);
+
+    mutex_t mutex = MUTEX_INIT;
     mutex_lock(&mutex);
     /* -2 is to adjust the real value */
     int res = hwtimer_set(ticks - 2, hwtimer_releasemutex, &mutex);

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(struct 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.
@@ -62,32 +70,28 @@ int mutex_init(struct mutex_t *mutex);
  * @return 1 if mutex was unlocked, now it is locked.
  * @return 0 if the mutex was locked.
  */
-int mutex_trylock(struct mutex_t *mutex);
+int mutex_trylock(mutex_t *mutex);
 
 /**
- * @brief Tries to get a mutex, blocking.
+ * @brief Locks a mutex, blocking.
  *
- * @param[in] mutex Mutex object to lock. Has to be initialized first. Must not
- *                  be NULL.
- *
- * @return 1 getting the mutex was successful
- * @return <1 there was an error.
+ * @param[in] mutex Mutex object to lock. Has to be initialized first. Must not be NULL.
  */
-int mutex_lock(struct mutex_t *mutex);
+void mutex_lock(mutex_t *mutex);
 
 /**
  * @brief Unlocks the mutex.
  *
  * @param[in] mutex Mutex object to unlock, must not be NULL.
  */
-void mutex_unlock(struct mutex_t *mutex);
+void mutex_unlock(mutex_t *mutex);
 
 /**
  * @brief Unlocks the mutex and sends the current thread to sleep
  *
  * @param[in] mutex Mutex object to unlock, must not be NULL.
  */
-void mutex_unlock_and_sleep(struct mutex_t *mutex);
+void mutex_unlock_and_sleep(mutex_t *mutex);
 
 #endif /* __MUTEX_H_ */
 /** @} */

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`)

core/mutex.c

@@ -35,24 +35,13 @@
 
 static void mutex_wait(struct mutex_t *mutex);
 
-int mutex_init(struct mutex_t *mutex)
-{
-    mutex->val = 0;
-
-    mutex->queue.priority = 0;
-    mutex->queue.data = 0;
-    mutex->queue.next = NULL;
-
-    return 1;
-}
-
 int mutex_trylock(struct mutex_t *mutex)
 {
     DEBUG("%s: trylocking to get mutex. val: %u\n", sched_active_thread->name, mutex->val);
     return (atomic_set_return(&mutex->val, 1) == 0);
 }
 
-int mutex_lock(struct mutex_t *mutex)
+void mutex_lock(struct mutex_t *mutex)
 {
     DEBUG("%s: trying to get mutex. val: %u\n", sched_active_thread->name, mutex->val);
 
@@ -60,8 +49,6 @@ int mutex_lock(struct mutex_t *mutex)
         /* mutex was locked. */
         mutex_wait(mutex);
     }
-
-    return 1;
 }
 
 static void mutex_wait(struct mutex_t *mutex)

drivers/cc110x/cc1100_phy.c

@@ -82,7 +82,7 @@ static packet_monitor_t packet_monitor;
 static handler_entry_t handlers[MAX_PACKET_HANDLERS];
 static const pm_table_t handler_table;
 static const char *cc1100_event_handler_name = "cc1100_event_handler";
-static mutex_t cc1100_mutex;
+static mutex_t cc1100_mutex = MUTEX_INIT;
 volatile int cc1100_mutex_pid;
 static vtimer_t cc1100_watch_dog;
 static timex_t cc1100_watch_dog_period;
@@ -175,7 +175,6 @@ void cc1100_phy_init(void)
 
     /* Initialize mutex */
     cc1100_mutex_pid = -1;
-    mutex_init(&cc1100_mutex);
 
     /* Allocate event numbers and start cc1100 event process */
     cc1100_event_handler_pid = thread_create(event_handler_stack, sizeof(event_handler_stack), PRIORITY_CC1100, CREATE_STACKTEST,

drivers/sht11/sht11.c

@@ -85,7 +85,7 @@ static void transmission_start(void);
 static inline void clk_signal(void);
 
 /* mutex for exclusive measurement operation */
-mutex_t sht11_mutex;
+mutex_t sht11_mutex = MUTEX_INIT;
 
 /*---------------------------------------------------------------------------*/
 static inline void clk_signal(void)
@@ -266,7 +266,6 @@ static uint8_t measure(uint8_t *p_value, uint8_t *p_checksum, uint8_t mode)
 void sht11_init(void)
 {
     sht11_temperature_offset = 0;
-    mutex_init(&sht11_mutex);
     SHT11_INIT;
     hwtimer_wait(11 * HWTIMER_TICKS(1000));
 }

sys/net/network_layer/sixlowpan/lowpan.c

@@ -121,14 +121,14 @@ uint8_t frag_size;
 uint8_t reas_buf[512];
 uint8_t comp_buf[512];
 uint8_t first_frag = 0;
-mutex_t fifo_mutex;
+mutex_t fifo_mutex = MUTEX_INIT;
 
 int ip_process_pid = 0;
 int nd_nbr_cache_rem_pid = 0;
 int contexts_rem_pid = 0;
 int transfer_pid = 0;
 
-mutex_t lowpan_context_mutex;
+mutex_t lowpan_context_mutex = MUTEX_INIT;
 
 /* registered upper layer threads */
 int sixlowpan_reg[SIXLOWPAN_MAX_REGISTERED];
@@ -1788,12 +1788,6 @@ int sixlowpan_lowpan_init(void)
     /* init mac-layer and radio transceiver */
     sixlowpan_mac_init();
 
-    /* init lowpan context mutex */
-    mutex_init(&lowpan_context_mutex);
-
-    /* init packet_fifo mutex */
-    mutex_init(&fifo_mutex);
-
     if (!ip_process_pid) {
         ip_process_pid = thread_create(ip_process_buf, IP_PROCESS_STACKSIZE,
                                        PRIORITY_MAIN - 1, CREATE_STACKTEST,

sys/net/routing/etx_beaconing.c

@@ -98,7 +98,7 @@ static etx_neighbor_t candidates[ETX_MAX_CANDIDATE_NEIGHBORS];
  * In this time, no packet may be handled, otherwise it could assume values
  * from the last round to count for this round.
  */
-mutex_t etx_mutex;
+mutex_t etx_mutex = MUTEX_INIT;
 //Transceiver command for sending ETX probes
 transceiver_command_t tcmd;
 
@@ -141,7 +141,6 @@ void etx_show_candidates(void)
 
 void etx_init_beaconing(ipv6_addr_t *address)
 {
-    mutex_init(&etx_mutex);
     own_address = address;
     //set code
     puts("ETX BEACON INIT");

sys/net/routing/rpl/rpl.c

@@ -50,8 +50,8 @@ char addr_str[IPV6_MAX_ADDR_STR_LEN];
 rpl_of_t *rpl_objective_functions[NUMBER_IMPLEMENTED_OFS];
 rpl_routing_entry_t rpl_routing_table[RPL_MAX_ROUTING_ENTRIES];
 unsigned int rpl_process_pid;
-mutex_t rpl_recv_mutex;
-mutex_t rpl_send_mutex;
+mutex_t rpl_recv_mutex = MUTEX_INIT;
+mutex_t rpl_send_mutex = MUTEX_INIT;
 msg_t rpl_msg_queue[RPL_PKT_RECV_BUF_SIZE];
 char rpl_process_buf[RPL_PROCESS_STACKSIZE];
 uint8_t rpl_buffer[BUFFER_SIZE - LL_HDR_LEN];
@@ -73,8 +73,6 @@ rpl_of_t *rpl_get_of_for_ocp(uint16_t ocp)
 
 uint8_t rpl_init(int if_id)
 {
-    mutex_init(&rpl_send_mutex);
-    mutex_init(&rpl_recv_mutex);
     rpl_instances_init();
 
     /* initialize routing table */

sys/vtimer/vtimer.c

@@ -343,8 +343,7 @@ int vtimer_sleep(timex_t time)
 
     int ret;
     vtimer_t t;
-    mutex_t mutex;
-    mutex_init(&mutex);
+    mutex_t mutex = MUTEX_INIT;
     mutex_lock(&mutex);
 
     t.action = vtimer_callback_unlock;

tests/test_mutex_unlock_and_sleep/main.c

@@ -22,7 +22,7 @@
 #include "thread.h"
 #include "mutex.h"
 
-static mutex_t mutex;
+static mutex_t mutex = MUTEX_INIT;
 static volatile int indicator, count;
 
 static char stack[KERNEL_CONF_STACKSIZE_MAIN];
@@ -42,7 +42,6 @@ int main(void)
 {
     indicator = 0;
     count = 0;
-    mutex_init(&mutex);
 
     thread_create(stack,
                   sizeof(stack),

tests/test_pthread_condition_variable/main.c

@@ -22,7 +22,7 @@
 #include "pthread.h"
 #include "thread.h"
 
-static mutex_t mutex;
+static mutex_t mutex = MUTEX_INIT;
 static struct pthread_cond_t cv;
 static volatile int is_finished;
 static volatile long count;
@@ -55,7 +55,6 @@ int main(void)
     count = 0;
     is_finished = 0;
     expected_value = 1000*1000;
-    mutex_init(&mutex);
     pthread_cond_init(&cv, NULL);
 
     int pid = thread_create(stack,

tests/test_thread_cooperation/main.c

@@ -26,7 +26,7 @@
 
 #define PROBLEM 12
 
-mutex_t mtx;
+mutex_t mtx = MUTEX_INIT;
 
 volatile int storage = 1;
 int main_id;
@@ -63,8 +63,6 @@ int main(void)
 {
     main_id = thread_getpid();
 
-    mutex_init(&mtx);
-
     printf("Problem: %d\n", PROBLEM);
 
     msg_t args[PROBLEM];