[net-next PATCH 4/4] samples/bpf: allow make to be run from samples/bpf/ directory

Jesper Dangaard Brouer
2016-04-26T11:09:34Z

It is not intuitive that 'make' must be run from the top level
directory with argument "samples/bpf/" to compile these eBPF samples.

Introduce a kbuild make file trick that allow make to be run from the
"samples/bpf/" directory itself. It basically change to the top level
directory and call "make samples/bpf/" with the "/" slash after the
directory name.

Also add a clean target that only cleans this directory, by taking
advantage of the kbuild external module setting M=$PWD.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
---
samples/bpf/Makefile | 8 ++++++++
samples/bpf/README.rst | 3 +++
2 files changed, 11 insertions(+)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 7ac66f5bbbf5..7370dfee482f 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -85,6 +85,14 @@ HOSTLOADLIBES_test_overhead += -lelf -lrt
# make samples/bpf/ LLC=~/git/llvm/build/bin/llc
LLC ?= llc

+# Trick to allow make to be run from this directory
+all:
+ $(MAKE) -C ../../ $$PWD/
+
+clean:
+ $(MAKE) -C ../../ M=$$PWD clean
+ @rm -f *~
+
# Verify LLVM compiler is available and bpf target is supported
.PHONY: verify_cmd_llc verify_target_bpf

diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
index 3e1ac05d8e7c..3a9e6c4099aa 100644
--- a/samples/bpf/README.rst
+++ b/samples/bpf/README.rst
@@ -47,6 +47,9 @@ For compiling goto kernel top level build directory and run make like::

Do notice the "/" slash after the directory name.

+It is also possible to call make from this directory. This will just
+hide the the invocation of make as above with the appended "/".
+
Manually compiling LLVM with 'bpf' support
------------------------------------------