_serial_fifo_tx_blocking_buf这个问题正常吗？

请问在使用serial_v2的时候，这个问题正常吗？还是说我的理解存在错误？
原代码

static rt_size_t _serial_fifo_tx_blocking_buf(struct rt_device        *dev,
                                                 rt_off_t          pos,
                                           const void             *buffer,
                                                rt_size_t          size)
{
struct rt_serial_device *serial;
struct rt_serial_tx_fifo *tx_fifo = RT_NULL;
RT_ASSERT(dev != RT_NULL);
if (size == 0) return 0;
serial = (struct rt_serial_device *)dev;
RT_ASSERT((serial != RT_NULL) && (buffer != RT_NULL));
tx_fifo = (struct rt_serial_tx_fifo *) serial->serial_tx;
RT_ASSERT(tx_fifo != RT_NULL);
/* When serial transmit in tx_blocking mode,
 * if the activated mode is RT_TRUE, it will return directly */
if (tx_fifo->activated == RT_TRUE)  return 0;
tx_fifo->activated = RT_TRUE;
rt_size_t length = size;
rt_size_t offset = 0;
while (size)
{
    /* Copy one piece of data into the ringbuffer at a time
     * until the length of the data is equal to size */
    tx_fifo->put_size = rt_ringbuffer_put(&(tx_fifo->rb),
                                           (rt_uint8_t *)buffer + offset,
                                           size);
    offset += tx_fifo->put_size;
    size -= tx_fifo->put_size;
    /* Call the transmit interface for transmission */
    serial->ops->transmit(serial,
                         (rt_uint8_t *)buffer + offset,
                         tx_fifo->put_size,
                         RT_SERIAL_TX_BLOCKING);
    /* Waiting for the transmission to complete */
    rt_completion_wait(&(tx_fifo->tx_cpt), RT_WAITING_FOREVER);
}
return length;
}

异常点在于offset，尚未发出去，就递增了。

offset += tx_fifo->put_size;
    size -= tx_fifo->put_size;

引导调用发送接口的时候，buffer + offset指针偏移的位置不正确。

serial->ops->transmit(serial,
                         (rt_uint8_t *)buffer + offset,
                         tx_fifo->put_size,
                         RT_SERIAL_TX_BLOCKING);

修改后代号，数据发送正常。

static rt_size_t _serial_fifo_tx_blocking_buf(struct rt_device        *dev,
                                                 rt_off_t          pos,
                                           const void             *buffer,
                                                rt_size_t          size)
{
struct rt_serial_device *serial;
struct rt_serial_tx_fifo *tx_fifo = RT_NULL;
RT_ASSERT(dev != RT_NULL);
if (size == 0) return 0;
serial = (struct rt_serial_device *)dev;
RT_ASSERT((serial != RT_NULL) && (buffer != RT_NULL));
tx_fifo = (struct rt_serial_tx_fifo *) serial->serial_tx;
RT_ASSERT(tx_fifo != RT_NULL);
/* When serial transmit in tx_blocking mode,
 * if the activated mode is RT_TRUE, it will return directly */
if (tx_fifo->activated == RT_TRUE)  return 0;
tx_fifo->activated = RT_TRUE;
rt_size_t length = size;
rt_size_t offset = 0;
while (size)
{
    /* Copy one piece of data into the ringbuffer at a time
     * until the length of the data is equal to size */
    tx_fifo->put_size = rt_ringbuffer_put(&(tx_fifo->rb),
                                           (rt_uint8_t *)buffer + offset,
                                           size);
    /* Call the transmit interface for transmission */
    serial->ops->transmit(serial,
                         (rt_uint8_t *)buffer + offset,
                         tx_fifo->put_size,
                         RT_SERIAL_TX_BLOCKING);