[PATCH] libnvdimm: Enable unit test infrastructure compile checks

[PATCH] libnvdimm: Enable unit test infrastructure compile checks

[Dan Williams]

The infrastructure to mock core libnvdimm routines for unit testing
purposes is prone to bitrot relative to refactoring of that core.
Arrange for the unit test core to be built when CONFIG_COMPILE_TEST=y.
This does not result in a functional unit test environment, it is only a
helper for 0day to catch unit test build regressions.

Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/Kconfig  |   11 +++++++++++
 drivers/nvdimm/Makefile |    4 ++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
index 54500798f23a..57d3a6c3ac70 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig
@@ -118,4 +118,15 @@ config NVDIMM_KEYS
 	depends on ENCRYPTED_KEYS
 	depends on (LIBNVDIMM=ENCRYPTED_KEYS) || LIBNVDIMM=m
 
+config NVDIMM_TEST_BUILD
+	bool "Build the unit test core"
+	depends on COMPILE_TEST
+	default COMPILE_TEST
+	help
+	  Build the core of the unit test infrastructure.  The result of
+	  this build is non-functional for unit test execution, but it
+	  otherwise helps catch build errors induced by changes to the
+	  core devm_memremap_pages() implementation and other
+	  infrastructure.
+
 endif
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
index 6f2a088afad6..40080c120363 100644
--- a/drivers/nvdimm/Makefile
+++ b/drivers/nvdimm/Makefile
@@ -28,3 +28,7 @@ libnvdimm-$(CONFIG_BTT) += btt_devs.o
 libnvdimm-$(CONFIG_NVDIMM_PFN) += pfn_devs.o
 libnvdimm-$(CONFIG_NVDIMM_DAX) += dax_devs.o
 libnvdimm-$(CONFIG_NVDIMM_KEYS) += security.o
+
+TOOLS := ../../tools
+TEST_SRC := $(TOOLS)/testing/nvdimm/test
+obj-$(CONFIG_NVDIMM_TEST_BUILD) := $(TEST_SRC)/iomap.o

Re: [PATCH] libnvdimm: Enable unit test infrastructure compile checks

[Christoph Hellwig]

On Mon, Jun 17, 2019 at 01:52:27PM -0700, Dan Williams wrote:
> The infrastructure to mock core libnvdimm routines for unit testing
> purposes is prone to bitrot relative to refactoring of that core.
> Arrange for the unit test core to be built when CONFIG_COMPILE_TEST=y.
> This does not result in a functional unit test environment, it is only a
> helper for 0day to catch unit test build regressions.

Looks fine:

Reviewed-by: Christoph Hellwig <hch@lst.de>

I'm still curious what the point of hiding kernel code in tools/
is vs fully integrating it with the build system.

Re: [PATCH] libnvdimm: Enable unit test infrastructure compile checks

[Dan Williams]

On Wed, Jun 19, 2019 at 4:23 AM Christoph Hellwig <hch@lst.de> wrote:
>
> On Mon, Jun 17, 2019 at 01:52:27PM -0700, Dan Williams wrote:
> > The infrastructure to mock core libnvdimm routines for unit testing
> > purposes is prone to bitrot relative to refactoring of that core.
> > Arrange for the unit test core to be built when CONFIG_COMPILE_TEST=y.
> > This does not result in a functional unit test environment, it is only a
> > helper for 0day to catch unit test build regressions.
>
> Looks fine:
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
>
> I'm still curious what the point of hiding kernel code in tools/
> is vs fully integrating it with the build system.

The separation of tools/ is due to way the "--wrap=" ldflag behaves.
It can only wrap symbols across a module linking boundary. So to
produce a setup where libnvdimm is ingesting faked responses it all
needs to be built as external modules and relinked.

It's an inelegant way to get some test coverage beyond what qemu-kvm
can do, my hope is that down the road I can use the new Kunit
infrastructure to do something similar in a cleaner / more formal way.