On Tue, Jan 15, 2019 at 12:26:31PM +0200, Joel Nider wrote:

It is important to understand the existing framework when implementing
a new verb. The majority of existing API functions are implemented using
the write syscall, but this has been superceded by the ioctl syscall
for new commands. This patch updates the documentation regarding how
to go about implementing a new verb, focusing on the new ioctl
interface.

The documentation is far from complete, but this is a good step in the
right direction. Future patches can add more detail according to need.
Also, the interface is still undergoing substantial changes so an
effort was made to document only the stable parts so as to avoid
incorrect information since documentation changes tend to lag behind
code changes.

I think this is a horrible direction to take.  The current document is
clearly for _users_.  All this documentation you've added is for kernel
hackers.  It needs to go in a different file, or not be added at all.