Included in this patch:

- (From John Tyner) Move allocation of memory out of send_control_msg. With
the allocation moved to open, control messages are less expensive since
they don't allocate and free memory every time.
- (From John Tyner) Change the behaviour of send_control_msg to return 0 on
success instead of the number of bytes transferred.
- Clean up of a couple down_interruptible() calls that weren't checking for
failure
- Rewrite of proc fs entries to use one file per value instead of parsing
in the kernel