How to get drive letter from device object/ device name in kernel- mode

Hi folks,
Could anybody tell me how to get the drive letter from device object
or device name from the kernel mode.
Regards,
Sreejith S R
IBM Global Services Pvt. Ltd.
Golden Enclave, Airport Road,
Bangalore -17

Phone : 91-80-526 2355/7117 ext: 3024
Fax : 91-80-527 7374