Merge pull request #11660 from JulianHolzwarth/pr/xtimer_mutex_lock_t…

…imeout/_mutex_remove_thread_from_waiting_queue

core/mutex: use volatile pointer for blocking flag of _mutex_lock

core/include/mutex.h

@@ -23,6 +23,7 @@
 #define MUTEX_H
 
 #include <stddef.h>
+#include <stdint.h>
 
 #include "list.h"
 
@@ -87,7 +88,7 @@ static inline void mutex_init(mutex_t *mutex)
  * @return 1 if mutex was unlocked, now it is locked.
  * @return 0 if the mutex was locked.
  */
-int _mutex_lock(mutex_t *mutex, int blocking);
+int _mutex_lock(mutex_t *mutex, volatile uint8_t *blocking);
 
 /**
  * @brief Tries to get a mutex, non-blocking.
@@ -100,7 +101,8 @@ int _mutex_lock(mutex_t *mutex, int blocking);
  */
 static inline int mutex_trylock(mutex_t *mutex)
 {
-    return _mutex_lock(mutex, 0);
+    volatile uint8_t blocking = 0;
+    return _mutex_lock(mutex, &blocking);
 }
 
 /**
@@ -110,7 +112,8 @@ static inline int mutex_trylock(mutex_t *mutex)
  */
 static inline void mutex_lock(mutex_t *mutex)
 {
-    _mutex_lock(mutex, 1);
+    volatile uint8_t blocking = 1;
+    _mutex_lock(mutex, &blocking);
 }
 
 /**

core/mutex.c

@@ -32,7 +32,7 @@
 #define ENABLE_DEBUG    (0)
 #include "debug.h"
 
-int _mutex_lock(mutex_t *mutex, int blocking)
+int _mutex_lock(mutex_t *mutex, volatile uint8_t *blocking)
 {
     unsigned irqstate = irq_disable();
 
@@ -46,7 +46,7 @@ int _mutex_lock(mutex_t *mutex, int blocking)
         irq_restore(irqstate);
         return 1;
     }
-    else if (blocking) {
+    else if (*blocking) {
         thread_t *me = (thread_t*)sched_active_thread;
         DEBUG("PID[%" PRIkernel_pid "]: Adding node to mutex queue: prio: %"
               PRIu32 "\n", sched_active_pid, (uint32_t)me->priority);

sys/xtimer/xtimer.c

@@ -262,7 +262,7 @@ int xtimer_mutex_lock_timeout(mutex_t *mutex, uint64_t timeout)
         t.arg = (void *)((mutex_thread_t *)&mt);
         xtimer_set64(&t, timeout);
     }
-    int ret = _mutex_lock(mutex, mt.blocking);
+    int ret = _mutex_lock(mutex, &mt.blocking);
     if (ret == 0) {
         return -1;
     }