examples/bpf: move from test directory

The bpf folder didn't actual contain a test application, but instead
basic examples of BPF code for use with testpmd. Therefore we can
move it to the `examples` folder. Being different, it also needs
a README with it, explaining what it is and how to use it. References
to the code from the testpmd docs are suitably updated.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

MAINTAINERS

@@ -1229,7 +1229,7 @@ F: doc/guides/howto/telemetry.rst
 BPF - EXPERIMENTAL
 M: Konstantin Ananyev <konstantin.ananyev@intel.com>
 F: lib/librte_bpf/
-F: test/bpf/
+F: examples/bpf/
 F: test/test/test_bpf.c
 F: doc/guides/prog_guide/bpf_lib.rst
 

doc/guides/testpmd_app_ug/testpmd_funcs.rst

@@ -4503,20 +4503,20 @@ For example:
 
 .. code-block:: console
 
-   cd test/bpf
+   cd examples/bpf
    clang -O2 -target bpf -c t1.c
 
 Then to load (and JIT compile) t1.o at RX queue 0, port 1::
 
 .. code-block:: console
 
-   testpmd> bpf-load rx 1 0 J ./dpdk.org/test/bpf/t1.o
+   testpmd> bpf-load rx 1 0 J ./dpdk.org/examples/bpf/t1.o
 
 To load (not JITed) t1.o at TX queue 0, port 0::
 
 .. code-block:: console
 
-   testpmd> bpf-load tx 0 0 - ./dpdk.org/test/bpf/t1.o
+   testpmd> bpf-load tx 0 0 - ./dpdk.org/examples/bpf/t1.o
 
 bpf-unload
 ~~~~~~~~~~
@@ -4529,4 +4529,4 @@ For example to unload BPF filter from TX queue 0, port 0:
 
 .. code-block:: console
 
-   testpmd> bpf-load tx 0 0 - ./dpdk.org/test/bpf/t1.o
+   testpmd> bpf-unload tx 0 0

examples/bpf/README

@@ -0,0 +1,8 @@
+This folder contains example BPF programs for use with the DPDK bpf
+library. To get details of each program and how to compile it, see
+the header on the '.c' file itself.
+
+Once compiled, these example programs can be loaded into `testpmd`
+for execution on a packet stream. See `bpf-load` and `bpf-unload`
+commands documented in the `Testpmd Application User Guide` for
+details on how to do so.

examples/bpf/meson.build

@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2019 Intel Corporation
+
+# This contains BPF example code for use in testing BPF with testpmd,
+# therefore it should not be built as part of a meson build.
+build=false