bpf, docs: Fix ordering of bpf documentation

This commit fixes the display of the BPF documentation in the sidebar
when rendered as HTML.

Before this patch, the sidebar would render as follows for some
sections:

| BPF Documentation
  |- BPF Type Format (BTF)
    |- BPF Type Format (BTF)

This was due to creating a heading in index.rst followed by
a sphinx toctree, where the file referenced carries the same
title as the section heading.

To fix this I applied a pattern that has been established in other
subfolders of Documentation:

1. Re-wrote index.rst to have a single toctree
2. Split the sections out in to their own files

Additionally maps.rst and programs.rst make use of a glob pattern to
include map_* or prog_* rst files in their toctree, meaning future map
or program type documentation will be automatically included.

Signed-off-by: Dave Tucker <dave@dtucker.co.uk>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1a1eed800e7b9dc13b458de113a489641519b0cc.1636749493.git.dave@dtucker.co.uk

1 files changed, 13 insertions, 84 deletions

diff --git a/Documentation/bpf/index.rst b/Documentation/bpf/index.rst
index 37f273a7e8b6..413f50101eca 100644
--- a/Documentation/bpf/index.rst
+++ b/Documentation/bpf/index.rst
@@ -12,97 +12,26 @@ BPF instruction-set.
 The Cilium project also maintains a `BPF and XDP Reference Guide`_
 that goes into great technical depth about the BPF Architecture.
 
-libbpf
-======
-
-Documentation/bpf/libbpf/libbpf.rst is a userspace library for loading and interacting with bpf programs.
-
-BPF Type Format (BTF)
-=====================
-
 .. toctree::
    :maxdepth: 1
 
+   libbpf/index
    btf
-
-
-Frequently asked questions (FAQ)
-================================
-
-Two sets of Questions and Answers (Q&A) are maintained.
-
-.. toctree::
-   :maxdepth: 1
-
-   bpf_design_QA
-   bpf_devel_QA
-
-Syscall API
-===========
-
-The primary info for the bpf syscall is available in the `man-pages`_
-for `bpf(2)`_. For more information about the userspace API, see
-Documentation/userspace-api/ebpf/index.rst.
-
-Helper functions
-================
-
-* `bpf-helpers(7)`_ maintains a list of helpers available to eBPF programs.
-
-
-Program types
-=============
-
-.. toctree::
-   :maxdepth: 1
-
-   prog_cgroup_sockopt
-   prog_cgroup_sysctl
-   prog_flow_dissector
-   bpf_lsm
-   prog_sk_lookup
-
-
-Map types
-=========
-
-.. toctree::
-   :maxdepth: 1
-
-   map_cgroup_storage
-
-
-Testing and debugging BPF
-=========================
-
-.. toctree::
-   :maxdepth: 1
-
-   drgn
-   s390
-
-
-Licensing
-=========
-
-.. toctree::
-   :maxdepth: 1
-
+   faq
+   syscall_api
+   helpers
+   programs
+   maps
    bpf_licensing
+   test_debug
+   other
 
+.. only::  subproject and html
 
-Other
-=====
-
-.. toctree::
-   :maxdepth: 1
+   Indices
+   =======
 
-   ringbuf
-   llvm_reloc
+   * :ref:`genindex`
 
 .. Links:
-.. _networking-filter: ../networking/filter.rst
-.. _man-pages: https://www.kernel.org/doc/man-pages/
-.. _bpf(2): https://man7.org/linux/man-pages/man2/bpf.2.html
-.. _bpf-helpers(7): https://man7.org/linux/man-pages/man7/bpf-helpers.7.html
-.. _BPF and XDP Reference Guide: https://docs.cilium.io/en/latest/bpf/
+.. _BPF and XDP Reference Guide: https://docs.cilium.io/en/latest/bpf/
\ No newline at end of file