[PATCH bpf 0/2] Two minor bpf doc updates

[PATCH bpf 0/2] Two minor bpf doc updates

[Daniel Borkmann]

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!

Daniel Borkmann (2):
  bpf, doc: update design qa to reflect kern_version requirement
  bpf, doc: add note for libbpf's stand-alone build

 Documentation/bpf/bpf_design_QA.rst | 11 +++++------
 tools/lib/bpf/README.rst            | 14 ++++++++++++++
 2 files changed, 19 insertions(+), 6 deletions(-)

-- 
2.9.5

[PATCH bpf 1/2] bpf, doc: update design qa to reflect kern_version requirement

[Daniel Borkmann]

Update the bpf_design_QA.rst to also reflect recent changes in
6c4fc209fcf9 ("bpf: remove useless version check for prog load").

Suggested-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---
 Documentation/bpf/bpf_design_QA.rst | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst
index 6780a6d..7cc9e36 100644
--- a/Documentation/bpf/bpf_design_QA.rst
+++ b/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?
 -------------------------------------------
-- 
2.9.5

[PATCH bpf 2/2] bpf, doc: add note for libbpf's stand-alone build

[Daniel Borkmann]

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>
---
 tools/lib/bpf/README.rst | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/tools/lib/bpf/README.rst b/tools/lib/bpf/README.rst
index 056f383..607aae4 100644
--- 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
 =====
 
-- 
2.9.5

Re: [PATCH bpf 0/2] Two minor bpf doc updates

[Alexei Starovoitov]

On Mon, Jan 07, 2019 at 10:57:16PM +0100, Daniel Borkmann wrote:
> 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!

Applied, Thanks