Re: [PATCH 2/3] selftests: add membarrier syscall test

On Tue, Sep 1, 2015 at 10:11 AM, Mathieu Desnoyers
[off-list ref] wrote:

----- On Aug 31, 2015, at 2:54 AM, Michael Ellerman mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org wrote:

quoted

On Fri, 2015-07-10 at 16:58 -0400, Mathieu Desnoyers wrote:

quoted

From: Pranith Kumar <redacted>

This patch adds a self test for the membarrier system call.

CC: Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>

Sorry I only just saw this due to some over zealous filtering on my end.

quoted

diff --git a/tools/testing/selftests/membarrier/Makefile

b/tools/testing/selftests/membarrier/Makefile
new file mode 100644
index 0000000..877a503

--- /dev/null
+++ b/tools/testing/selftests/membarrier/Makefile

@@ -0,0 +1,11 @@
+CFLAGS += -g -I../../../../usr/include/
+
+all:
+    $(CC) $(CFLAGS) membarrier_test.c -o membarrier_test

+TEST_PROGS := membarrier_test

You don't need to specify the rule, the implict one will do exactly the same,
so you can just do:

TEST_PROGS := membarrier_test

all: $(TEST_PROGS)

quoted

diff --git a/tools/testing/selftests/membarrier/membarrier_test.c

b/tools/testing/selftests/membarrier/membarrier_test.c
new file mode 100644
index 0000000..3c9f217

--- /dev/null
+++ b/tools/testing/selftests/membarrier/membarrier_test.c

@@ -0,0 +1,71 @@
+#define _GNU_SOURCE
+#define __EXPORTED_HEADERS__

Why are you exporting that?

I suspect to try and get around the "Attempt to use kernel headers from user
space" warning.

But you're correctly building against the installed headers, not the kernel
headers, so you don't need to do that.

Just to make sure I understand: should we expect that
everyone will issue "make headers_install" on their system
before doing a make kselftest ?

I see that a few selftests (e.g. memfd) are adding the
source tree include paths to the compiler include paths,
which I guess is to ensure that the kselftest will
work even if the system headers are not up to date.

It would be really nice if there were a clean way for selftests to
include the kernel headers.  Perhaps make should build the exportable
headers somewhere as a dependency of kselftests.

--Andy