bpf, doc: add note for libbpf's stand-alone build

Given this came up couple of times, add a note to libbpf's readme
about the semi-automated mirror for a stand-alone build which is
officially managed by BPF folks. While at it, also explicitly state
the libbpf license in the readme file.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/lib/bpf/README.rst b/tools/lib/bpf/README.rst
index 056f383107226082d5a7e693f8f888651a84520b..607aae40f4edaa95514bc76403ea42d8ed580748 100644 (file)
--- a/tools/lib/bpf/README.rst
+++ b/tools/lib/bpf/README.rst
@@ -132,6 +132,20 @@ For example, if current state of ``libbpf.map`` is:
 Format of version script and ways to handle ABI changes, including
 incompatible ones, described in details in [1].
 
+Stand-alone build
+=================
+
+Under https://github.com/libbpf/libbpf there is a (semi-)automated
+mirror of the mainline's version of libbpf for a stand-alone build.
+
+However, all changes to libbpf's code base must be upstreamed through
+the mainline kernel tree.
+
+License
+=======
+
+libbpf is dual-licensed under LGPL 2.1 and BSD 2-Clause.
+
 Links
 =====