serial port buffer commit

[David Chow]

Hi all,

I am writing a kernel thread for serial port communication. If the 
serial character device file is opened by a filp_open() or manipulating 
using a struct file in the kernel, how can I know whether the previous 
written buffer has commit or not? Similarly, how do I know is there any 
data ready for read for non blocking access? Thanks.

regards,
David Chow