[Kernel] message 可以返回消息的实际大小 (#7709)

18 files changed, 73 insertions, 56 deletions

diff --git a/bsp/allwinner/libraries/sunxi-hal/hal/source/sdmmc/osal/os/RT-Thread/os_queue.c b/bsp/allwinner/libraries/sunxi-hal/hal/source/sdmmc/osal/os/RT-Thread/os_queue.c
index a90eeaae65..c0e773f13d 100644
--- a/bsp/allwinner/libraries/sunxi-hal/hal/source/sdmmc/osal/os/RT-Thread/os_queue.c
+++ b/bsp/allwinner/libraries/sunxi-hal/hal/source/sdmmc/osal/os/RT-Thread/os_queue.c
@@ -150,7 +150,7 @@ OS_Status OS_QueueReceive(OS_Queue_t *queue, void *item, OS_Time_t waitMS)
     OS_HANDLE_ASSERT(OS_QueueIsValid(queue), queue->handle);
 
     ret = rt_mq_recv(queue->handle, item, queue->itemSize, OS_CalcWaitTicks(waitMS));
-    if (ret != RT_EOK) {
+    if (ret < 0) {
         OS_DBG("%s() fail @ %d, %"OS_TIME_F" ms\n", __func__, __LINE__, (unsigned int)waitMS);
         return OS_FAIL;
     }
diff --git a/bsp/allwinner/libraries/sunxi-hal/osal/src/hal_queue.c b/bsp/allwinner/libraries/sunxi-hal/osal/src/hal_queue.c
index d44c784469..091aa32c49 100644
--- a/bsp/allwinner/libraries/sunxi-hal/osal/src/hal_queue.c
+++ b/bsp/allwinner/libraries/sunxi-hal/osal/src/hal_queue.c
@@ -182,7 +182,7 @@ int hal_queue_recv(hal_queue_t queue, void *buffer, int timeout)
     }
 
     ret = rt_mq_recv(queue, buffer, queue->msg_size, timeout);
-    if (ret != RT_EOK)
+    if (ret < 0)
     {
         return -2;
     }
diff --git a/bsp/fujitsu/mb9x/mb9bf500r/application.c b/bsp/fujitsu/mb9x/mb9bf500r/application.c
index 1cbd0c2d83..b61f6e05f0 100644
--- a/bsp/fujitsu/mb9x/mb9bf500r/application.c
+++ b/bsp/fujitsu/mb9x/mb9bf500r/application.c
@@ -74,7 +74,7 @@ void rt_init_thread_entry(void *parameter)
 
     while(1)
     {
-        if (rt_mq_recv(&mq, &msg, sizeof(msg), RT_WAITING_FOREVER) == RT_EOK)
+        if (rt_mq_recv(&mq, &msg, sizeof(msg), RT_WAITING_FOREVER) >= 0)
         {
             switch(msg.type)
             {
diff --git a/bsp/imxrt/libraries/MIMXRT1050/MIMXRT1052/drivers/fsl_os_abstraction_rtthread.c b/bsp/imxrt/libraries/MIMXRT1050/MIMXRT1052/drivers/fsl_os_abstraction_rtthread.c
index 524744c251..6b8fc6ca16 100644
--- a/bsp/imxrt/libraries/MIMXRT1050/MIMXRT1052/drivers/fsl_os_abstraction_rtthread.c
+++ b/bsp/imxrt/libraries/MIMXRT1050/MIMXRT1052/drivers/fsl_os_abstraction_rtthread.c
@@ -788,7 +788,7 @@ osa_status_t OSA_MsgQGet(osa_msgq_handle_t msgqHandle, osa_msg_handle_t pMessage
     {
         timeoutTicks = rt_tick_from_millisecond(millisec);
     }
-    if (RT_EOK != rt_mq_recv(handler, pMessage, handler->msg_size, timeoutTicks))
+    if (rt_mq_recv(handler, pMessage, handler->msg_size, timeoutTicks) < 0)
     {
         osaStatus = KOSA_StatusTimeout; /* not able to send it to the queue? */
     }
diff --git a/bsp/imxrt/libraries/MIMXRT1060/MIMXRT1060/drivers/fsl_os_abstraction_rtthread.c b/bsp/imxrt/libraries/MIMXRT1060/MIMXRT1060/drivers/fsl_os_abstraction_rtthread.c
index 524744c251..6b8fc6ca16 100644
--- a/bsp/imxrt/libraries/MIMXRT1060/MIMXRT1060/drivers/fsl_os_abstraction_rtthread.c
+++ b/bsp/imxrt/libraries/MIMXRT1060/MIMXRT1060/drivers/fsl_os_abstraction_rtthread.c
@@ -788,7 +788,7 @@ osa_status_t OSA_MsgQGet(osa_msgq_handle_t msgqHandle, osa_msg_handle_t pMessage
     {
         timeoutTicks = rt_tick_from_millisecond(millisec);
     }
-    if (RT_EOK != rt_mq_recv(handler, pMessage, handler->msg_size, timeoutTicks))
+    if (rt_mq_recv(handler, pMessage, handler->msg_size, timeoutTicks) < 0)
     {
         osaStatus = KOSA_StatusTimeout; /* not able to send it to the queue? */
     }
diff --git a/bsp/imxrt/libraries/MIMXRT1061/MIMXRT1061/drivers/fsl_os_abstraction_rtthread.c b/bsp/imxrt/libraries/MIMXRT1061/MIMXRT1061/drivers/fsl_os_abstraction_rtthread.c
index 524744c251..6b8fc6ca16 100644
--- a/bsp/imxrt/libraries/MIMXRT1061/MIMXRT1061/drivers/fsl_os_abstraction_rtthread.c
+++ b/bsp/imxrt/libraries/MIMXRT1061/MIMXRT1061/drivers/fsl_os_abstraction_rtthread.c
@@ -788,7 +788,7 @@ osa_status_t OSA_MsgQGet(osa_msgq_handle_t msgqHandle, osa_msg_handle_t pMessage
     {
         timeoutTicks = rt_tick_from_millisecond(millisec);
     }
-    if (RT_EOK != rt_mq_recv(handler, pMessage, handler->msg_size, timeoutTicks))
+    if (rt_mq_recv(handler, pMessage, handler->msg_size, timeoutTicks) < 0)
     {
         osaStatus = KOSA_StatusTimeout; /* not able to send it to the queue? */
     }
diff --git a/bsp/imxrt/libraries/MIMXRT1170/MIMXRT1176/drivers/fsl_os_abstraction_rtthread.c b/bsp/imxrt/libraries/MIMXRT1170/MIMXRT1176/drivers/fsl_os_abstraction_rtthread.c
index 524744c251..6b8fc6ca16 100644
--- a/bsp/imxrt/libraries/MIMXRT1170/MIMXRT1176/drivers/fsl_os_abstraction_rtthread.c
+++ b/bsp/imxrt/libraries/MIMXRT1170/MIMXRT1176/drivers/fsl_os_abstraction_rtthread.c
@@ -788,7 +788,7 @@ osa_status_t OSA_MsgQGet(osa_msgq_handle_t msgqHandle, osa_msg_handle_t pMessage
     {
         timeoutTicks = rt_tick_from_millisecond(millisec);
     }
-    if (RT_EOK != rt_mq_recv(handler, pMessage, handler->msg_size, timeoutTicks))
+    if (rt_mq_recv(handler, pMessage, handler->msg_size, timeoutTicks) < 0)
     {
         osaStatus = KOSA_StatusTimeout; /* not able to send it to the queue? */
     }
diff --git a/bsp/stm32/stm32mp157a-st-ev1/board/ports/dma_sample.c b/bsp/stm32/stm32mp157a-st-ev1/board/ports/dma_sample.c
index 30b0c99496..49cf2b2757 100644
--- a/bsp/stm32/stm32mp157a-st-ev1/board/ports/dma_sample.c
+++ b/bsp/stm32/stm32mp157a-st-ev1/board/ports/dma_sample.c
@@ -50,7 +50,7 @@ static void serial_thread_entry(void *parameter)
     {
         rt_memset(&msg, 0, sizeof(msg));
         result = rt_mq_recv(&rx_mq, &msg, sizeof(msg), RT_WAITING_FOREVER);
-        if (result == RT_EOK)
+        if (result >= 0)
         {
             rx_length = rt_device_read(msg.dev, 0, rx_buffer, msg.size);
             rx_buffer[rx_length] = '\0';
diff --git a/components/drivers/usb/usbdevice/class/hid.c b/components/drivers/usb/usbdevice/class/hid.c
index d2bb05ed24..59816df4a9 100644
--- a/components/drivers/usb/usbdevice/class/hid.c
+++ b/components/drivers/usb/usbdevice/class/hid.c
@@ -627,7 +627,7 @@ static void hid_thread_entry(void* parameter)
     hiddev = (struct hid_s *)parameter;
     while(1)
     {
-        if(rt_mq_recv(&hiddev->hid_mq, &report, sizeof(report),RT_WAITING_FOREVER) != RT_EOK )
+        if(rt_mq_recv(&hiddev->hid_mq, &report, sizeof(report),RT_WAITING_FOREVER) < 0)
             continue;
         HID_Report_Received(&report);
     }
diff --git a/components/drivers/usb/usbdevice/core/usbdevice_core.c b/components/drivers/usb/usbdevice/core/usbdevice_core.c
index 28e673d2a8..b373150800 100644
--- a/components/drivers/usb/usbdevice/core/usbdevice_core.c
+++ b/components/drivers/usb/usbdevice/core/usbdevice_core.c
@@ -2160,7 +2160,7 @@ static void rt_usbd_thread_entry(void* parameter)
 
         /* receive message */
         if(rt_mq_recv(&usb_mq, &msg, sizeof(struct udev_msg),
-                    RT_WAITING_FOREVER) != RT_EOK )
+                    RT_WAITING_FOREVER) < 0)
             continue;
 
         device = rt_usbd_find_device(msg.dcd);
diff --git a/components/drivers/usb/usbhost/core/hub.c b/components/drivers/usb/usbhost/core/hub.c
index 549fe373d4..bf55be3452 100644
--- a/components/drivers/usb/usbhost/core/hub.c
+++ b/components/drivers/usb/usbhost/core/hub.c
@@ -659,8 +659,8 @@ static void rt_usbh_hub_thread_entry(void* parameter)
         struct uhost_msg msg;
 
         /* receive message */
-        if(rt_mq_recv(hcd->usb_mq, &msg, sizeof(struct uhost_msg), RT_WAITING_FOREVER)
-            != RT_EOK ) continue;
+        if (rt_mq_recv(hcd->usb_mq, &msg, sizeof(struct uhost_msg), RT_WAITING_FOREVER) < 0)
+            continue;
 
         //RT_DEBUG_LOG(RT_DEBUG_USB, ("msg type %d\n", msg.type));
 
@@ -711,7 +711,7 @@ void rt_usbh_hub_init(uhcd_t hcd)
     {
         LOG_E("hcd->roothub: allocate buffer failed.");
         return;
-    }         
+    }
     rt_memset(hcd->roothub, 0, sizeof(struct uhub));
     hcd->roothub->is_roothub = RT_TRUE;
     hcd->roothub->hcd = hcd;
diff --git a/components/libc/cplusplus/os/cxx_queue.h b/components/libc/cplusplus/os/cxx_queue.h
index f6b91e1a21..46257d35c3 100644
--- a/components/libc/cplusplus/os/cxx_queue.h
+++ b/components/libc/cplusplus/os/cxx_queue.h
@@ -62,7 +62,7 @@ public:
         else
             tick = rt_tick_from_millisecond(millisec);
 
-        return rt_mq_recv(&mID, &data, sizeof(data), tick) == RT_EOK;
+        return rt_mq_recv(&mID, &data, sizeof(data), tick) >= 0;
     }
 
 private:
diff --git a/components/libc/posix/ipc/mqueue.c b/components/libc/posix/ipc/mqueue.c
index 4b5905ef48..22d2854770 100644
--- a/components/libc/posix/ipc/mqueue.c
+++ b/components/libc/posix/ipc/mqueue.c
@@ -233,7 +233,7 @@ ssize_t mq_receive(mqd_t id, char *msg_ptr, size_t msg_len, unsigned *msg_prio)
     }
 
     result = rt_mq_recv(mqdes->mq, msg_ptr, msg_len, RT_WAITING_FOREVER);
-    if (result == RT_EOK)
+    if (result >= 0)
         return rt_strlen(msg_ptr);
 
     rt_set_errno(EBADF);
@@ -288,7 +288,7 @@ ssize_t mq_timedreceive(mqd_t                  id,
         tick = rt_timespec_to_tick(abs_timeout);
 
     result = rt_mq_recv(mqdes->mq, msg_ptr, msg_len, tick);
-    if (result == RT_EOK)
+    if (result >= 0)
         return rt_strlen(msg_ptr);
 
     if (result == -RT_ETIMEOUT)
@@ -358,19 +358,19 @@ RTM_EXPORT(mq_close);
 /**
  * @brief    This function will remove a message queue (REALTIME).
  *
- * @note    The mq_unlink() function shall remove the message queue named by the string name. 
- *          If one or more processes have the message queue open when mq_unlink() is called, 
- *          destruction of the message queue shall be postponed until all references to the message queue have been closed. 
+ * @note    The mq_unlink() function shall remove the message queue named by the string name.
+ *          If one or more processes have the message queue open when mq_unlink() is called,
+ *          destruction of the message queue shall be postponed until all references to the message queue have been closed.
  *          However, the mq_unlink() call need not block until all references have been closed; it may return immediately.
- * 
- *          After a successful call to mq_unlink(), reuse of the name shall subsequently cause mq_open() to behave as if 
- *          no message queue of this name exists (that is, mq_open() will fail if O_CREAT is not set, 
+ *
+ *          After a successful call to mq_unlink(), reuse of the name shall subsequently cause mq_open() to behave as if
+ *          no message queue of this name exists (that is, mq_open() will fail if O_CREAT is not set,
  *          or will create a new message queue if O_CREAT is set).
- * 
+ *
  * @param    name  is the name of the message queue.
  *
- * @return   Upon successful completion, the function shall return a value of zero. 
- *           Otherwise, the named message queue shall be unchanged by this function call, 
+ * @return   Upon successful completion, the function shall return a value of zero.
+ *           Otherwise, the named message queue shall be unchanged by this function call,
  *           and the function shall return a value of -1 and set errno to indicate the error.
  *
  * @warning  This function can ONLY be called in the thread context, you can use RT_DEBUG_IN_THREAD_CONTEXT to
@@ -384,9 +384,9 @@ RTM_EXPORT(mq_close);
  *              The named message queue does not exist.
  *           The mq_unlink() function may fail if:
  *              [ENAMETOOLONG]
- *              The length of the name argument exceeds {_POSIX_PATH_MAX} on systems that do not support the XSI option 
- *              or exceeds {_XOPEN_PATH_MAX} on XSI systems,or has a pathname component that is longer than {_POSIX_NAME_MAX} on systems that do 
- *              not support the XSI option or longer than {_XOPEN_NAME_MAX} on XSI systems.A call to mq_unlink() with a name argument that contains 
+ *              The length of the name argument exceeds {_POSIX_PATH_MAX} on systems that do not support the XSI option
+ *              or exceeds {_XOPEN_PATH_MAX} on XSI systems,or has a pathname component that is longer than {_POSIX_NAME_MAX} on systems that do
+ *              not support the XSI option or longer than {_XOPEN_NAME_MAX} on XSI systems.A call to mq_unlink() with a name argument that contains
  *              the same message queue name as was previously used in a successful mq_open() call shall not give an [ENAMETOOLONG] error.
  */
 int mq_unlink(const char *name)
diff --git a/documentation/device/uart/uart.md b/documentation/device/uart/uart.md
index d49a005019..92ca9b4bf8 100644
--- a/documentation/device/uart/uart.md
+++ b/documentation/device/uart/uart.md
@@ -575,7 +575,7 @@ static void serial_thread_entry(void *parameter)
         rt_memset(&msg, 0, sizeof(msg));
         /* Read messages from the message queue*/
         result = rt_mq_recv(&rx_mq, &msg, sizeof(msg), RT_WAITING_FOREVER);
-        if (result == RT_EOK)
+        if (result >= 0)
         {
             /*Read data from the serial port*/
             rx_length = rt_device_read(msg.dev, 0, rx_buffer, msg.size);
diff --git a/documentation/thread-comm/thread-comm.md b/documentation/thread-comm/thread-comm.md
index 4369752855..758c8defa5 100644
--- a/documentation/thread-comm/thread-comm.md
+++ b/documentation/thread-comm/thread-comm.md
@@ -595,7 +595,7 @@ static void thread1_entry(void *parameter)
     while (1)
     {
         /* Receive messages from the message queue */
-        if (rt_mq_recv(&mq, &buf, sizeof(buf), RT_WAITING_FOREVER) == RT_EOK)
+        if (rt_mq_recv(&mq, &buf, sizeof(buf), RT_WAITING_FOREVER) >= 0)
         {
             rt_kprintf("thread1: recv msg from msg queue, the content:%c\n", buf);
             if (cnt == 19)
@@ -784,7 +784,7 @@ void message_handler()
     struct msg msg_ptr; /* Local variable used to place the message */
 
     /* Receive messages from the message queue into msg_ptr */
-    if (rt_mq_recv(mq, (void*)&msg_ptr, sizeof(struct msg)) == RT_EOK)
+    if (rt_mq_recv(mq, (void*)&msg_ptr, sizeof(struct msg)) >= 0)
     {
         /* Successfully received the message, corresponding data processing is performed */
     }
diff --git a/examples/utest/testcases/kernel/messagequeue_tc.c b/examples/utest/testcases/kernel/messagequeue_tc.c
index c0ee2ef030..08d4049875 100644
--- a/examples/utest/testcases/kernel/messagequeue_tc.c
+++ b/examples/utest/testcases/kernel/messagequeue_tc.c
@@ -15,7 +15,7 @@
 #define MAX_MSGS    5
 
 static struct rt_messagequeue static_mq;
-static rt_uint8_t mq_buf[(MSG_SIZE + (rt_uint8_t)sizeof(rt_ubase_t)) * MAX_MSGS];
+static rt_uint8_t mq_buf[RT_MQ_BUF_SIZE(MSG_SIZE, MAX_MSGS)];
 
 static struct rt_thread mq_send_thread;
 static struct rt_thread mq_recv_thread;
@@ -111,14 +111,14 @@ static void mq_recv_case(rt_mq_t testmq)
     for (int var = 0; var < MAX_MSGS + 1; ++var)
     {
         ret = rt_mq_recv(testmq, &recv_buf[var], sizeof(recv_buf[0]), RT_WAITING_FOREVER);
-        uassert_true(ret == RT_EOK);
+        uassert_true(ret >= 0);
         uassert_true(recv_buf[var] == (var + 1));
     }
 
     for (int var = 0; var < 3; ++var)
     {
         ret = rt_mq_recv(testmq, &recv_buf[var], sizeof(recv_buf[0]), RT_WAITING_FOREVER);
-        uassert_true(ret == RT_EOK);
+        uassert_true(ret >= 0);
         uassert_true(recv_buf[var] == (var + 1));
     }
 }
diff --git a/include/rtthread.h b/include/rtthread.h
index ac1b8f12c2..dfcd1c413c 100644
--- a/include/rtthread.h
+++ b/include/rtthread.h
@@ -458,6 +458,16 @@ rt_err_t rt_mb_control(rt_mailbox_t mb, int cmd, void *arg);
 #endif
 
 #ifdef RT_USING_MESSAGEQUEUE
+
+struct rt_mq_message
+{
+    struct rt_mq_message *next;
+    rt_ssize_t length;
+};
+
+#define RT_MQ_BUF_SIZE(msg_size, max_msgs) \
+((RT_ALIGN((msg_size), RT_ALIGN_SIZE) + sizeof(struct rt_mq_message)) * (max_msgs))
+
 /*
  * message queue interface
  */
@@ -492,15 +502,15 @@ rt_err_t rt_mq_send_wait_killable(rt_mq_t     mq,
                          rt_size_t   size,
                          rt_int32_t  timeout);
 rt_err_t rt_mq_urgent(rt_mq_t mq, const void *buffer, rt_size_t size);
-rt_err_t rt_mq_recv(rt_mq_t    mq,
+rt_ssize_t rt_mq_recv(rt_mq_t    mq,
                     void      *buffer,
                     rt_size_t  size,
                     rt_int32_t timeout);
-rt_err_t rt_mq_recv_interruptible(rt_mq_t    mq,
+rt_ssize_t rt_mq_recv_interruptible(rt_mq_t    mq,
                     void      *buffer,
                     rt_size_t  size,
                     rt_int32_t timeout);
-rt_err_t rt_mq_recv_killable(rt_mq_t    mq,
+rt_ssize_t rt_mq_recv_killable(rt_mq_t    mq,
                     void      *buffer,
                     rt_size_t  size,
                     rt_int32_t timeout);
diff --git a/src/ipc.c b/src/ipc.c
index 3bd94b5b1b..d6c3717b9e 100644
--- a/src/ipc.c
+++ b/src/ipc.c
@@ -44,6 +44,7 @@
  * 2022-04-08     Stanley      Correct descriptions
  * 2022-10-15     Bernard      add nested mutex feature
  * 2022-10-16     Bernard      add prioceiling feature in mutex
+ * 2023-04-16     Xin-zheqi    redesigen queue recv and send function return real message size
  */
 
 #include <rtthread.h>
@@ -59,6 +60,7 @@
     #define __on_rt_object_put_hook(parent)         __ON_HOOK_ARGS(rt_object_put_hook, (parent))
 #endif
 
+#define GET_MESSAGEBYTE_ADDR(msg)               ((struct rt_mq_message *) msg + 1)
 #if defined(RT_USING_HOOK) && defined(RT_HOOK_USING_FUNC_PTR)
 extern void (*rt_object_trytake_hook)(struct rt_object *object);
 extern void (*rt_object_take_hook)(struct rt_object *object);
@@ -2858,12 +2860,6 @@ RTM_EXPORT(rt_mb_control);
  * @{
  */
 
-struct rt_mq_message
-{
-    struct rt_mq_message *next;
-};
-
-
 /**
  * @brief    Initialize a static messagequeue object.
  *
@@ -3300,8 +3296,11 @@ static rt_err_t _rt_mq_send_wait(rt_mq_t     mq,
 
     /* the msg is the new tailer of list, the next shall be NULL */
     msg->next = RT_NULL;
+
+    /* add the length */
+    ((struct rt_mq_message *)msg)->length = size;
     /* copy buffer */
-    rt_memcpy(msg + 1, buffer, size);
+    rt_memcpy(GET_MESSAGEBYTE_ADDR(msg), buffer, size);
 
     /* disable interrupt */
     level = rt_hw_interrupt_disable();
@@ -3355,7 +3354,7 @@ rt_err_t rt_mq_send_wait(rt_mq_t     mq,
 {
     return _rt_mq_send_wait(mq, buffer, size, timeout, RT_UNINTERRUPTIBLE);
 }
-RTM_EXPORT(rt_mq_send_wait)
+RTM_EXPORT(rt_mq_send_wait);
 
 rt_err_t rt_mq_send_wait_interruptible(rt_mq_t     mq,
                          const void *buffer,
@@ -3364,7 +3363,7 @@ rt_err_t rt_mq_send_wait_interruptible(rt_mq_t     mq,
 {
     return _rt_mq_send_wait(mq, buffer, size, timeout, RT_INTERRUPTIBLE);
 }
-RTM_EXPORT(rt_mq_send_wait_interruptible)
+RTM_EXPORT(rt_mq_send_wait_interruptible);
 
 rt_err_t rt_mq_send_wait_killable(rt_mq_t     mq,
                          const void *buffer,
@@ -3373,7 +3372,7 @@ rt_err_t rt_mq_send_wait_killable(rt_mq_t     mq,
 {
     return _rt_mq_send_wait(mq, buffer, size, timeout, RT_KILLABLE);
 }
-RTM_EXPORT(rt_mq_send_wait_killable)
+RTM_EXPORT(rt_mq_send_wait_killable);
 /**
  * @brief    This function will send a message to the messagequeue object.
  *           If there is a thread suspended on the messagequeue, the thread will be resumed.
@@ -3467,8 +3466,10 @@ rt_err_t rt_mq_urgent(rt_mq_t mq, const void *buffer, rt_size_t size)
     /* enable interrupt */
     rt_hw_interrupt_enable(level);
 
+    /* add the length */
+    ((struct rt_mq_message *)msg)->length = size;
     /* copy buffer */
-    rt_memcpy(msg + 1, buffer, size);
+    rt_memcpy(GET_MESSAGEBYTE_ADDR(msg), buffer, size);
 
     /* disable interrupt */
     level = rt_hw_interrupt_disable();
@@ -3536,10 +3537,10 @@ RTM_EXPORT(rt_mq_urgent);
  *           If use macro RT_WAITING_NO to set this parameter, which means that this
  *           function is non-blocking and will return immediately.
  *
- * @return   Return the operation status. When the return value is RT_EOK, the operation is successful.
+ * @return   Return the real length of the message. When the return value is larger than zero, the operation is successful.
  *           If the return value is any other values, it means that the mailbox release failed.
  */
-static rt_err_t _rt_mq_recv(rt_mq_t    mq,
+static rt_ssize_t _rt_mq_recv(rt_mq_t    mq,
                     void      *buffer,
                     rt_size_t  size,
                     rt_int32_t timeout,
@@ -3550,6 +3551,7 @@ static rt_err_t _rt_mq_recv(rt_mq_t    mq,
     struct rt_mq_message *msg;
     rt_uint32_t tick_delta;
     rt_err_t ret;
+    rt_size_t len;
 
     /* parameter check */
     RT_ASSERT(mq != RT_NULL);
@@ -3665,8 +3667,13 @@ static rt_err_t _rt_mq_recv(rt_mq_t    mq,
     /* enable interrupt */
     rt_hw_interrupt_enable(level);
 
+    /* get real message length */
+    len = ((struct rt_mq_message *)msg)->length;
+
+    if (len > size)
+        len = size;
     /* copy message */
-    rt_memcpy(buffer, msg + 1, size > mq->msg_size ? mq->msg_size : size);
+    rt_memcpy(buffer, GET_MESSAGEBYTE_ADDR(msg), len);
 
     /* disable interrupt */
     level = rt_hw_interrupt_disable();
@@ -3686,7 +3693,7 @@ static rt_err_t _rt_mq_recv(rt_mq_t    mq,
 
         rt_schedule();
 
-        return RT_EOK;
+        return len;
     }
 
     /* enable interrupt */
@@ -3694,10 +3701,10 @@ static rt_err_t _rt_mq_recv(rt_mq_t    mq,
 
     RT_OBJECT_HOOK_CALL(rt_object_take_hook, (&(mq->parent.parent)));
 
-    return RT_EOK;
+    return len;
 }
 
-rt_err_t rt_mq_recv(rt_mq_t    mq,
+rt_ssize_t rt_mq_recv(rt_mq_t    mq,
                     void      *buffer,
                     rt_size_t  size,
                     rt_int32_t timeout)
@@ -3706,7 +3713,7 @@ rt_err_t rt_mq_recv(rt_mq_t    mq,
 }
 RTM_EXPORT(rt_mq_recv);
 
-rt_err_t rt_mq_recv_interruptible(rt_mq_t    mq,
+rt_ssize_t rt_mq_recv_interruptible(rt_mq_t    mq,
                     void      *buffer,
                     rt_size_t  size,
                     rt_int32_t timeout)
@@ -3715,7 +3722,7 @@ rt_err_t rt_mq_recv_interruptible(rt_mq_t    mq,
 }
 RTM_EXPORT(rt_mq_recv_interruptible);
 
-rt_err_t rt_mq_recv_killable(rt_mq_t    mq,
+rt_ssize_t rt_mq_recv_killable(rt_mq_t    mq,
                     void      *buffer,
                     rt_size_t  size,
                     rt_int32_t timeout)