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

Message ID 20160426110932.20716.51360.stgit@firesoul
State New
Headers show

Commit Message

Jesper Dangaard Brouer April 26, 2016, 11:09 a.m. UTC
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(+)


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Comments

Alexei Starovoitov April 26, 2016, 2:35 p.m. UTC | #1
On Tue, Apr 26, 2016 at 01:09:32PM +0200, Jesper Dangaard Brouer wrote:
> 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 *~
> +

nice trick!

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David Laight April 27, 2016, 1:15 p.m. UTC | #2
From: Alexei Starovoitov
> Sent: 26 April 2016 15:35
> On Tue, Apr 26, 2016 at 01:09:32PM +0200, Jesper Dangaard Brouer wrote:
> > 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 *~
> > +
> 
> nice trick!

Another nice 'trick' is to write a GNUmakefie containing the local rules.
GNU make will read it in preference to Makefile and makefile.

	David

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Patch
diff mbox

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
 ------------------------------------------