Merge branch 'bpf-doc-updates'

Daniel Borkmann says:

====================
Two trivial doc follow-ups to i) remove deprecated kern_version
mentioning in the design qa and ii) to mention stand-alone build
and license of libbpf. Thanks!
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Documentation/bpf/bpf_design_QA.rst

@@ -157,12 +157,11 @@ Q: Does BPF have a stable ABI?
 ------------------------------
 A: YES. BPF instructions, arguments to BPF programs, set of helper
 functions and their arguments, recognized return codes are all part
-of ABI. However when tracing programs are using bpf_probe_read() helper
-to walk kernel internal datastructures and compile with kernel
-internal headers these accesses can and will break with newer
-kernels. The union bpf_attr -> kern_version is checked at load time
-to prevent accidentally loading kprobe-based bpf programs written
-for a different kernel. Networking programs don't do kern_version check.
+of ABI. However there is one specific exception to tracing programs
+which are using helpers like bpf_probe_read() to walk kernel internal
+data structures and compile with kernel internal headers. Both of these
+kernel internals are subject to change and can break with newer kernels
+such that the program needs to be adapted accordingly.
 
 Q: How much stack space a BPF program uses?
 -------------------------------------------

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
 =====