US Patent 8209704 Techniques for user space and kernel space communication

Described are techniques for intermodule communication between a first code module and a second code module wherein one of the first and second code modules executing in user space and the other of the first and second code modules executing in kernel space. A shared memory portion includes storage for one or more commands. A first first-in-first-out (FIFO) structure is used to send a location in the shared memory portion from the first to the second code module. A second FIFO structure is used for sending a location in the shared memory portion from the second to the first code module. The first code module stores command data for a command at a first location in the shared memory portion. A command is issued from the first to the second code module by sending the first location using the first FIFO structure.