rt_mq_send 函数问题

发布于 2010-07-19 11:20:33 浏览：6290 订阅该版

```
rt_err_t rt_mq_send (rt_mq_t mq, void* buffer, rt_size_t size)
{
	register rt_ubase_t temp;
	struct rt_mq_message *msg;

/* greater than one message size */
	if (size > mq->msg_size) return -RT_ERROR;

#ifdef RT_USING_HOOK
	if (rt_object_put_hook != RT_NULL) rt_object_put_hook(&(mq->parent.parent));
#endif

/* disable interrupt */
	temp = rt_hw_interrupt_disable();

/* get a free list, there must be an empty item */
	msg = (struct rt_mq_message*)mq->msg_queue_free;
	/* message queue is full */
	if (msg == RT_NULL)
	{
		/* enable interrupt */
		rt_hw_interrupt_enable(temp);

return -RT_EFULL;
	}
	/* move free list pointer */
	mq->msg_queue_free = msg->next;

/* enable interrupt */
	rt_hw_interrupt_enable(temp);

/* copy buffer */
	rt_memcpy(msg + 1, buffer, size);

/* disable interrupt */
	temp = rt_hw_interrupt_disable();
	/* link msg to message queue */
	if (mq->msg_queue_tail != RT_NULL)
	{
		/* if the tail exists, */
		((struct rt_mq_message*)mq->msg_queue_tail)->next = msg;  //这里指定tail的下个msg
	}
	/* the msg is the new tail of list, the next shall be NULL */
	msg->next = RT_NULL;

/* set new tail */
	mq->msg_queue_tail = msg;                   //这里怎么又把msg替代tail呢？
	/* if the head is empty, set head */
	if (mq->msg_queue_head == RT_NULL)mq->msg_queue_head = msg; //如果head,tail都为空，那么msg不是占用两个空间？

/* increase message entry */
	mq->entry ++;

/* resume suspended thread */
	if( !rt_list_isempty(&mq->parent.suspend_thread) )
	{
		rt_ipc_object_resume(&(mq->parent));

/* enable interrupt */
		rt_hw_interrupt_enable(temp);

rt_schedule();
		return RT_EOK;
	}

/* enable interrupt */
	rt_hw_interrupt_enable(temp);

return RT_EOK;
} 
```

这个函数用中断开启和屏蔽很多次啊，能不能优化一下。