Did you notice the comment above the function? ;-)
You should really add the new ioctls to compat_sys_ioctl, not
to the COMPATIBLE_IOCTL() list, in order to make the behavior
consistent between 32 and 64 bit user space. The main difference
is that all ioctl commands that are hardcoded in the functions
get called before trying to call the file system specific
This should be _IOW, not _IOR.
Otherwise looks good.