fix the conflicting file.

examples/kernel/SConscript

@@ -19,6 +19,7 @@ semaphore_priority.c
 semaphore_buffer_worker.c
 semaphore_producer_consumer.c
 mutex_simple.c
+mutex_priority.c
 event_simple.c
 mbox_simple.c
 mbox_send_wait.c

examples/kernel/mutex_priority.c

@@ -0,0 +1,425 @@
+/*
+ * 创建7个进程，tid20、tid21、tid22、tid23、tid24、tid25、tid26、tid27、tid28、tid29
+ * 各任务优先级分别为20、21、22、23、24、25、26、27、28、29，
+ * 其中tid26最先获得锁，tid22不需要使用到互斥锁，其他所有进程均需要使用互斥锁，
+ * 通过各个进程的打印信息，观察各个进程获取到互斥锁后，优先级变化情况
+ */
+#include <rtthread.h>
+#include "tc_comm.h"
+
+static rt_thread_t tid20 = RT_NULL;
+static rt_thread_t tid21 = RT_NULL;
+static rt_thread_t tid22 = RT_NULL;
+static rt_thread_t tid23 = RT_NULL;
+static rt_thread_t tid24 = RT_NULL;
+static rt_thread_t tid25 = RT_NULL;
+static rt_thread_t tid26 = RT_NULL;
+static rt_thread_t tid27 = RT_NULL;
+static rt_thread_t tid28 = RT_NULL;
+static rt_thread_t tid29 = RT_NULL;
+
+static rt_mutex_t mutex = RT_NULL;
+
+static void thread20_entry(void* parameter)
+{
+    rt_err_t result;
+    rt_tick_t tick;
+
+    rt_kprintf("[%d] thread20 run!\n", rt_tick_get());
+    rt_thread_delay(30);
+    rt_kprintf("[%d] thread20 wake!\n", rt_tick_get());
+
+    result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
+    if (result != RT_EOK)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+    }
+    rt_kprintf("[%d] thread20 take!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 5)
+    {
+        rt_kprintf("[%d] thread20, init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid20->init_priority, tid20->current_priority);
+    }
+    rt_mutex_release(mutex);
+    rt_kprintf("[%d] thread20 exit!\n", rt_tick_get());
+}
+
+static void thread21_entry(void* parameter)
+{
+    rt_err_t result;
+    rt_tick_t tick;
+    rt_kprintf("[%d] thread21 run!\n", rt_tick_get());
+    rt_thread_delay(25);
+    rt_kprintf("[%d] thread21 wake!\n", rt_tick_get());
+
+    result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
+    if (result != RT_EOK)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+    }
+    rt_kprintf("[%d] thread21 take!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 5)
+    {
+        rt_kprintf("[%d] thread21, init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid21->init_priority, tid21->current_priority);
+    }
+    rt_mutex_release(mutex);
+    rt_kprintf("[%d] thread21 exit!\n", rt_tick_get());
+
+}
+
+static void thread22_entry(void* parameter)
+{
+    rt_tick_t tick;
+
+    rt_kprintf("[%d] thread22 run!\n", rt_tick_get());
+    rt_thread_delay(20);
+    rt_kprintf("[%d] thread22 wake!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 100)
+    {
+        rt_kprintf("[%d] thread22 running..., init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid22->init_priority, tid22->current_priority);
+        rt_thread_delay(2);
+    }
+    rt_kprintf("[%d] thread22 exit!\n", rt_tick_get());
+}
+
+static void thread23_entry(void* parameter)
+{
+    rt_err_t result;
+    rt_tick_t tick;
+    rt_kprintf("[%d] thread23 run!\n", rt_tick_get());
+    rt_thread_delay(15);
+    rt_kprintf("[%d] thread23 wake!\n", rt_tick_get());
+
+    result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
+    if (result != RT_EOK)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+    }
+    rt_kprintf("[%d] thread23 take!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 5)
+    {
+        rt_kprintf("[%d] thread23, init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid23->init_priority, tid23->current_priority);
+    }
+    rt_mutex_release(mutex);
+    rt_kprintf("[%d] thread23 exit!\n", rt_tick_get());
+}
+
+static void thread24_entry(void* parameter)
+{
+    rt_err_t result;
+    rt_tick_t tick;
+
+    rt_kprintf("[%d] thread24 run!\n", rt_tick_get());
+    rt_thread_delay(10);
+    rt_kprintf("[%d] thread24 wake!\n", rt_tick_get());
+
+    result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
+    if (result != RT_EOK)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+    }
+    rt_kprintf("[%d] thread24 take!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 5)
+    {
+        rt_kprintf("[%d] thread24, init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid24->init_priority, tid24->current_priority);
+    }
+    rt_mutex_release(mutex);
+    rt_kprintf("[%d] thread24 exit!\n", rt_tick_get());
+}
+
+static void thread25_entry(void* parameter)
+{
+    rt_err_t result;
+    rt_tick_t tick;
+    rt_kprintf("[%d] thread25 run!\n", rt_tick_get());
+    rt_thread_delay(5);
+    rt_kprintf("[%d] thread25 wake!\n", rt_tick_get());
+
+    result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
+    if (result != RT_EOK)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+    }
+    rt_kprintf("[%d] thread25 take!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 5)
+    {
+        rt_kprintf("[%d] thread25, init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid25->init_priority, tid25->current_priority);
+    }
+    rt_mutex_release(mutex);
+    rt_kprintf("[%d] thread25 exit!\n", rt_tick_get());
+}
+
+static void thread26_entry(void* parameter)
+{
+    rt_tick_t tick;
+    rt_err_t result;
+
+    rt_kprintf("[%d] thread26 run!\n", rt_tick_get());
+
+    result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
+    if (result != RT_EOK)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+    }
+    rt_kprintf("[%d] thread26 take!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 50)
+    {
+        rt_kprintf("[%d] thread26, init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid26->init_priority, tid26->current_priority);
+        rt_thread_delay(1);
+    }
+    rt_mutex_release(mutex);
+    rt_kprintf("[%d] thread26 exit!\n", rt_tick_get());
+}
+
+static void thread27_entry(void* parameter)
+{
+    rt_tick_t tick;
+    rt_err_t result;
+
+    rt_kprintf("[%d] thread27 run!\n", rt_tick_get());
+    rt_thread_delay(35);
+    rt_kprintf("[%d] thread27 wake!\n", rt_tick_get());
+
+    result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
+    if (result != RT_EOK)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+    }
+    rt_kprintf("[%d] thread27 take!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 5)
+    {
+        rt_kprintf("[%d] thread27, init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid27->init_priority, tid27->current_priority);
+    }
+    rt_mutex_release(mutex);
+    rt_kprintf("[%d] thread27 exit!\n", rt_tick_get());
+}
+
+static void thread28_entry(void* parameter)
+{
+    rt_tick_t tick;
+    rt_err_t result;
+
+    rt_kprintf("[%d] thread28 run!\n", rt_tick_get());
+    rt_thread_delay(40);
+    rt_kprintf("[%d] thread28 wake!\n", rt_tick_get());
+
+    result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
+    if (result != RT_EOK)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+    }
+    rt_kprintf("[%d] thread28 take!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 5)
+    {
+        rt_kprintf("[%d] thread28, init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid28->init_priority, tid28->current_priority);
+    }
+    rt_mutex_release(mutex);
+    rt_kprintf("[%d] thread28 exit!\n", rt_tick_get());
+}
+
+static void thread29_entry(void* parameter)
+{
+    rt_tick_t tick;
+    rt_err_t result;
+
+    rt_kprintf("[%d] thread29 run!\n", rt_tick_get());
+    rt_thread_delay(45);
+    rt_kprintf("[%d] thread29 wake!\n", rt_tick_get());
+
+    result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
+    if (result != RT_EOK)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+    }
+    rt_kprintf("[%d] thread29 take!\n", rt_tick_get());
+
+    tick = rt_tick_get();
+    while (rt_tick_get() - tick < 5)
+    {
+        rt_kprintf("[%d] thread29, init_priority=%d, current_priority=%d\n",
+                rt_tick_get(), tid29->init_priority, tid29->current_priority);
+    }
+    rt_mutex_release(mutex);
+    rt_kprintf("[%d] thread29 exit!\n", rt_tick_get());
+}
+
+static int mutex_simple_init()
+{
+    /* 创建互斥锁 */
+    mutex = rt_mutex_create("mutex", RT_IPC_FLAG_FIFO);
+    if (mutex == RT_NULL)
+    {
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+        return 0;
+    }
+
+    tid29 = rt_thread_create("t29",
+                            thread29_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 29, THREAD_TIMESLICE);
+    if (tid29 != RT_NULL)
+        rt_thread_startup(tid29);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    tid28 = rt_thread_create("t28",
+                            thread28_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 28, THREAD_TIMESLICE);
+    if (tid28 != RT_NULL)
+        rt_thread_startup(tid28);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    tid27 = rt_thread_create("t27",
+                            thread27_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 27, THREAD_TIMESLICE);
+    if (tid27 != RT_NULL)
+        rt_thread_startup(tid27);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    tid26 = rt_thread_create("t26",
+                            thread26_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 26, THREAD_TIMESLICE);
+    if (tid26 != RT_NULL)
+        rt_thread_startup(tid26);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    tid25 = rt_thread_create("t25",
+                            thread25_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 25, THREAD_TIMESLICE);
+    if (tid25 != RT_NULL)
+        rt_thread_startup(tid25);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    tid24 = rt_thread_create("t24",
+                            thread24_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 24, THREAD_TIMESLICE);
+    if (tid24 != RT_NULL)
+        rt_thread_startup(tid24);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    tid23 = rt_thread_create("t23",
+                            thread23_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 23, THREAD_TIMESLICE);
+    if (tid23 != RT_NULL)
+        rt_thread_startup(tid23);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    tid22 = rt_thread_create("t22",
+                            thread22_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 22, THREAD_TIMESLICE);
+    if (tid22 != RT_NULL)
+        rt_thread_startup(tid22);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    tid21 = rt_thread_create("t21",
+                            thread21_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 21, THREAD_TIMESLICE);
+    if (tid21 != RT_NULL)
+        rt_thread_startup(tid21);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    tid20 = rt_thread_create("t20",
+                            thread20_entry, RT_NULL,
+                            THREAD_STACK_SIZE, 20, THREAD_TIMESLICE);
+    if (tid20 != RT_NULL)
+        rt_thread_startup(tid20);
+    else
+        tc_stat(TC_STAT_END | TC_STAT_FAILED);
+
+    return 0;
+}
+
+#ifdef RT_USING_TC
+static void _tc_cleanup()
+{
+    /* 调度器上锁，上锁后，将不再切换到其他线程，仅响应中断 */
+    rt_enter_critical();
+
+    /* 删除线程 */
+    if (tid20 != RT_NULL && tid20->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid20);
+    if (tid21 != RT_NULL && tid21->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid21);
+    if (tid22 != RT_NULL && tid22->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid22);
+    if (tid23 != RT_NULL && tid23->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid23);
+    if (tid24 != RT_NULL && tid24->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid24);
+    if (tid25 != RT_NULL && tid25->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid25);
+    if (tid26 != RT_NULL && tid26->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid26);
+    if (tid27 != RT_NULL && tid27->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid27);
+    if (tid28 != RT_NULL && tid28->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid28);
+    if (tid29 != RT_NULL && tid29->stat != RT_THREAD_CLOSE)
+        rt_thread_delete(tid29);
+
+    if (mutex != RT_NULL)
+    {
+        rt_mutex_delete(mutex);
+    }
+    rt_kprintf("test_done!\n");
+
+    /* 调度器解锁 */
+    rt_exit_critical();
+
+    /* 设置TestCase状态 */
+    tc_done(TC_STAT_PASSED);
+}
+
+int _tc_mutex_priority()
+{
+    /* 设置TestCase清理回调函数 */
+    tc_cleanup(_tc_cleanup);
+    mutex_simple_init();
+
+    /* 返回TestCase运行的最长时间 */
+    return 100;
+}
+/* 输出函数命令到finsh shell中 */
+FINSH_FUNCTION_EXPORT(_tc_mutex_priority, a priority rollover example of mutex);
+#else
+/* 用户应用入口 */
+int rt_application_init()
+{
+    mutex_simple_init();
+
+    return 0;
+}
+#endif

src/ipc.c

@@ -37,6 +37,7 @@
  * 2020-07-29     Meco Man     fix thread->event_set/event_info when received an 
  *                             event without pending
  * 2020-10-11     Meco Man     add value overflow-check code
+ * 2020-10-25     hupu         fix priority inversion bug of mutex
  */
 
 #include <rtthread.h>
@@ -190,6 +191,31 @@ rt_inline rt_err_t rt_ipc_list_resume_all(rt_list_t *list)
     return RT_EOK;
 }
 
+/**
+ * This function will get the highest priority from the specified
+ * list of threads
+ *
+ * @param list of the threads
+ *
+ * @return the highest priority
+ */
+rt_uint8_t rt_ipc_get_highest_priority(rt_list_t *list)
+{
+    struct rt_list_node *n;
+    struct rt_thread *sthread;
+    rt_uint8_t priority = RT_THREAD_PRIORITY_MAX - 1;
+
+    for (n = list->next; n != list; n = n->next)
+    {
+        sthread = rt_list_entry(n, struct rt_thread, tlist);
+
+        priority = priority < sthread->current_priority ?
+                    priority :
+                    sthread->current_priority;
+    }
+    return priority;
+}
+
 #ifdef RT_USING_SEMAPHORE
 /**
  * This function will initialize a semaphore and put it under control of
@@ -828,6 +854,7 @@ rt_err_t rt_mutex_release(rt_mutex_t mutex)
     register rt_base_t temp;
     struct rt_thread *thread;
     rt_bool_t need_schedule;
+    rt_uint8_t max_priority_in_queue = RT_THREAD_PRIORITY_MAX - 1;
 
     /* parameter check */
     RT_ASSERT(mutex != RT_NULL);
@@ -888,6 +915,22 @@ rt_err_t rt_mutex_release(rt_mutex_t mutex)
             /* set new owner and priority */
             mutex->owner             = thread;
             mutex->original_priority = thread->current_priority;
+
+            /* Priority adjustment occurs only when the following conditions
+             * are met simultaneously:
+             * 1.The type of mutex is RT_IPC_FLAG_FIFO;
+             * 2.The priority of the thread to be resumed is not equal to the
+             *   highest priority in the queue;
+             */
+            max_priority_in_queue = rt_ipc_get_highest_priority(&mutex->parent.suspend_thread);
+            if (mutex->parent.parent.flag == RT_IPC_FLAG_FIFO &&
+                thread->current_priority != max_priority_in_queue)
+            {
+                rt_thread_control(thread,
+                        RT_THREAD_CTRL_CHANGE_PRIORITY,
+                        &(max_priority_in_queue));
+            }
+
             if(mutex->hold < RT_MUTEX_HOLD_MAX)
             {
                 mutex->hold ++;