macvtap: update file current position

Signed-off-by: NZhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/macvtap.c

@@ -876,6 +876,8 @@ static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
 
 	ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK);
 	ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
+	if (ret > 0)
+		iocb->ki_pos = ret;
 out:
 	return ret;
 }