With the coming removal of jprobes, using ftrace callbacks is one of the
utilities that replace the jprobes functionality. Having a document that
explains how to use ftrace as such will help in the transition from jprobes
to ftrace. This document is for kernel developers that require attaching a
callback to a function within the kernel.

Link: http://lkml.kernel.org/r/150724519527.5014.10207042218696587159.stgit@devboxSigned-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
[jc: fixed one formatting issue that broke the docs build]
Signed-off-by: NJonathan Corbet <corbet@lwn.net>