diff mbox series

[RFC] drm/test: add a test suite for GEM objects backed by shmem

Message ID 20231023164541.92913-1-marpagan@redhat.com (mailing list archive)
State New, archived
Headers show
Series [RFC] drm/test: add a test suite for GEM objects backed by shmem | expand

Commit Message

Marco Pagani Oct. 23, 2023, 4:45 p.m. UTC
This patch introduces an initial KUnit test suite for GEM objects
backed by shmem buffers.

Signed-off-by: Marco Pagani <marpagan@redhat.com>
---
 drivers/gpu/drm/Kconfig                    |   1 +
 drivers/gpu/drm/tests/Makefile             |   3 +-
 drivers/gpu/drm/tests/drm_gem_shmem_test.c | 303 +++++++++++++++++++++
 3 files changed, 306 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/tests/drm_gem_shmem_test.c


base-commit: 3f5ba636d6987ddffeaa056dea1c524da63912f3

Comments

Maxime Ripard Oct. 24, 2023, 9:23 a.m. UTC | #1
Hi Marco,

On Mon, Oct 23, 2023 at 06:45:40PM +0200, Marco Pagani wrote:
> This patch introduces an initial KUnit test suite for GEM objects
> backed by shmem buffers.
> 
> Signed-off-by: Marco Pagani <marpagan@redhat.com>
> ---
>  drivers/gpu/drm/Kconfig                    |   1 +
>  drivers/gpu/drm/tests/Makefile             |   3 +-
>  drivers/gpu/drm/tests/drm_gem_shmem_test.c | 303 +++++++++++++++++++++
>  3 files changed, 306 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/tests/drm_gem_shmem_test.c
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 3eee8636f847..f0a77e3e04d7 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -84,6 +84,7 @@ config DRM_KUNIT_TEST
>  	select DRM_EXPORT_FOR_TESTS if m
>  	select DRM_KUNIT_TEST_HELPERS
>  	select DRM_EXEC
> +	select DRM_GEM_SHMEM_HELPER

I know that DRM_EXEC already stands out, but these should be ordered
alphabetically, so it should be before DRM_KUNIT_TEST_HELPERS.

>  	default KUNIT_ALL_TESTS
>  	help
>  	  This builds unit tests for DRM. This option is not useful for
> diff --git a/drivers/gpu/drm/tests/Makefile b/drivers/gpu/drm/tests/Makefile
> index ba7baa622675..b8227aab369e 100644
> --- a/drivers/gpu/drm/tests/Makefile
> +++ b/drivers/gpu/drm/tests/Makefile
> @@ -18,6 +18,7 @@ obj-$(CONFIG_DRM_KUNIT_TEST) += \
>  	drm_plane_helper_test.o \
>  	drm_probe_helper_test.o \
>  	drm_rect_test.o	\
> -	drm_exec_test.o
> +	drm_exec_test.o \
> +	drm_gem_shmem_test.o

Ditto.

>  CFLAGS_drm_mm_test.o := $(DISABLE_STRUCTLEAK_PLUGIN)
> diff --git a/drivers/gpu/drm/tests/drm_gem_shmem_test.c b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
> new file mode 100644
> index 000000000000..0bf6727f08d2
> --- /dev/null
> +++ b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
> @@ -0,0 +1,303 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * KUnit test suite for GEM objects backed by shmem buffers
> + *
> + * Copyright (C) 2023 Red Hat, Inc.
> + *
> + * Author: Marco Pagani <marpagan@redhat.com>
> + */
> +
> +#include <linux/dma-buf.h>
> +#include <linux/iosys-map.h>
> +#include <linux/sizes.h>
> +
> +#include <kunit/test.h>
> +
> +#include <drm/drm_device.h>
> +#include <drm/drm_drv.h>
> +#include <drm/drm_gem.h>
> +#include <drm/drm_gem_shmem_helper.h>
> +#include <drm/drm_kunit_helpers.h>
> +
> +#define TEST_SIZE		SZ_1M
> +#define TEST_BYTE		0xae
> +
> +struct fake_dev {
> +	struct drm_device drm_dev;
> +	struct device *dev;
> +};
> +
> +/* Test creating a shmem GEM object */
> +static void drm_gem_shmem_test_obj_create(struct kunit *test)
> +{
> +	struct fake_dev *fdev = test->priv;
> +	struct drm_gem_shmem_object *shmem;
> +
> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
> +	KUNIT_ASSERT_EQ(test, shmem->base.size, TEST_SIZE);
> +	KUNIT_ASSERT_NOT_NULL(test, shmem->base.filp);
> +	KUNIT_ASSERT_NOT_NULL(test, shmem->base.funcs);
> +
> +	drm_gem_shmem_free(shmem);
> +}
> +
> +/* Test creating a private shmem GEM object from a scatter/gather table */

Thanks for documenting those tests. I believe we should also document
what we expect from the test: should the test succeed? fail? if it
fails, what is the cause of failure?

Based on the following test, I think something like the following would
be good:

Test that creating a private shmem GEM object from a previously
allocated sg_table succeeds and is properly initialized

Feel free to change it to something else if you find something missing.

> +static void drm_gem_shmem_test_obj_create_private(struct kunit *test)
> +{
> +	struct fake_dev *fdev = test->priv;
> +	struct drm_gem_shmem_object *shmem;
> +	struct drm_gem_object *gem_obj;
> +	struct dma_buf buf_mock;
> +	struct dma_buf_attachment attach_mock;
> +	struct sg_table *sgt;
> +	char *buf;
> +	int ret;
> +
> +	/* Create a mock scatter/gather table */
> +	buf = kunit_kzalloc(test, TEST_SIZE, GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_NULL(test, buf);
> +
> +	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_NULL(test, sgt);
> +
> +	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +	sg_init_one(sgt->sgl, buf, TEST_SIZE);
> +
> +	/* Init a mock DMA-BUF */
> +	buf_mock.size = TEST_SIZE;
> +	attach_mock.dmabuf = &buf_mock;
> +
> +	gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
> +	KUNIT_ASSERT_EQ(test, gem_obj->size, TEST_SIZE);
> +	KUNIT_ASSERT_NULL(test, gem_obj->filp);
> +	KUNIT_ASSERT_NOT_NULL(test, gem_obj->funcs);
> +
> +	shmem = to_drm_gem_shmem_obj(gem_obj);
> +	KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);
> +
> +	/* The scatter/gather table is freed by drm_gem_shmem_free */
> +	drm_gem_shmem_free(shmem);
> +}

KUNIT_ASSERT_* will stop the execution of the test on failure, you
should probably use a bit more of KUNIT_EXPECT_* calls otherwise you'll
leak resources.

You also probably want to use a kunit_action to clean up and avoid that
whole discussion

> +
> +/* Test pinning backing pages */
> +static void drm_gem_shmem_test_pin_pages(struct kunit *test)
> +{
> +	struct fake_dev *fdev = test->priv;
> +	struct drm_gem_shmem_object *shmem;
> +	int i, ret;
> +
> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
> +	KUNIT_ASSERT_NULL(test, shmem->pages);
> +	KUNIT_ASSERT_EQ(test, shmem->pages_use_count, 0);
> +
> +	ret = drm_gem_shmem_pin(shmem);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +	KUNIT_ASSERT_NOT_NULL(test, shmem->pages);
> +	KUNIT_ASSERT_EQ(test, shmem->pages_use_count, 1);
> +
> +	for (i = 0; i < (shmem->base.size >> PAGE_SHIFT); i++)
> +		KUNIT_ASSERT_NOT_NULL(test, shmem->pages[i]);
> +
> +	drm_gem_shmem_unpin(shmem);
> +	KUNIT_ASSERT_NULL(test, shmem->pages);
> +	KUNIT_ASSERT_EQ(test, shmem->pages_use_count, 0);
> +
> +	drm_gem_shmem_free(shmem);
> +}
> +
> +/* Test creating a virtual mapping */
> +static void drm_gem_shmem_test_vmap(struct kunit *test)
> +{
> +	struct fake_dev *fdev = test->priv;
> +	struct drm_gem_shmem_object *shmem;
> +	struct iosys_map map;
> +	int ret, i;
> +
> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
> +	KUNIT_ASSERT_NULL(test, shmem->vaddr);
> +	KUNIT_ASSERT_EQ(test, shmem->vmap_use_count, 0);
> +
> +	ret = drm_gem_shmem_vmap(shmem, &map);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +	KUNIT_ASSERT_NOT_NULL(test, shmem->vaddr);
> +	KUNIT_ASSERT_EQ(test, shmem->vmap_use_count, 1);
> +	KUNIT_ASSERT_FALSE(test, iosys_map_is_null(&map));
> +
> +	iosys_map_memset(&map, 0, TEST_BYTE, TEST_SIZE);
> +	for (i = 0; i < TEST_SIZE; i++)
> +		KUNIT_ASSERT_EQ(test, iosys_map_rd(&map, i, u8), TEST_BYTE);
> +
> +	drm_gem_shmem_vunmap(shmem, &map);
> +	KUNIT_ASSERT_NULL(test, shmem->vaddr);
> +	KUNIT_ASSERT_EQ(test, shmem->vmap_use_count, 0);
> +
> +	drm_gem_shmem_free(shmem);
> +}
> +
> +/* Test exporting a scatter/gather table */
> +static void drm_gem_shmem_test_get_pages_sgt(struct kunit *test)
> +{
> +	struct fake_dev *fdev = test->priv;
> +	struct drm_gem_shmem_object *shmem;
> +	struct sg_table *sgt;
> +	struct scatterlist *sg;
> +	unsigned int si, len = 0;
> +	int ret;
> +
> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
> +
> +	ret = drm_gem_shmem_pin(shmem);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	sgt = drm_gem_shmem_get_sg_table(shmem);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
> +	KUNIT_ASSERT_NULL(test, shmem->sgt);
> +
> +	for_each_sgtable_sg(sgt, sg, si) {
> +		KUNIT_ASSERT_NOT_NULL(test, sg);
> +		len += sg->length;
> +	}
> +	KUNIT_ASSERT_GE(test, len, TEST_SIZE);
> +
> +	kfree(sgt);
> +	drm_gem_shmem_free(shmem);
> +}
> +
> +/* Test exporting a scatter/gather pinned table for PRIME */
> +static void drm_gem_shmem_test_get_sg_table(struct kunit *test)
> +{
> +	struct fake_dev *fdev = test->priv;
> +	struct drm_gem_shmem_object *shmem;
> +	struct sg_table *sgt;
> +	struct scatterlist *sg;
> +	unsigned int si, len = 0;
> +
> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
> +
> +	sgt = drm_gem_shmem_get_pages_sgt(shmem);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
> +	KUNIT_ASSERT_PTR_EQ(test, sgt, shmem->sgt);
> +
> +	for_each_sgtable_sg(sgt, sg, si) {
> +		KUNIT_ASSERT_NOT_NULL(test, sg);
> +		len += sg->length;
> +	}
> +	KUNIT_ASSERT_GE(test, len, TEST_SIZE);
> +
> +	/* The scatter/gather table is freed by drm_gem_shmem_free */
> +	drm_gem_shmem_free(shmem);
> +}
> +
> +/* Test updating madvise status */
> +static void drm_gem_shmem_test_madvise(struct kunit *test)
> +{
> +	struct fake_dev *fdev = test->priv;
> +	struct drm_gem_shmem_object *shmem;
> +	int ret;
> +
> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
> +	KUNIT_ASSERT_EQ(test, shmem->madv, 0);
> +
> +	ret = drm_gem_shmem_madvise(shmem, 1);
> +	KUNIT_ASSERT_TRUE(test, ret);
> +	KUNIT_ASSERT_EQ(test, shmem->madv, 1);
> +
> +	ret = drm_gem_shmem_madvise(shmem, -1);
> +	KUNIT_ASSERT_FALSE(test, ret);
> +	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
> +
> +	ret = drm_gem_shmem_madvise(shmem, 0);
> +	KUNIT_ASSERT_FALSE(test, ret);
> +	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
> +
> +	drm_gem_shmem_free(shmem);
> +}
> +
> +/* Test purging */
> +static void drm_gem_shmem_test_purge(struct kunit *test)
> +{
> +	struct fake_dev *fdev = test->priv;
> +	struct drm_gem_shmem_object *shmem;
> +	struct sg_table *sgt;
> +	int ret;
> +
> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
> +
> +	ret = drm_gem_shmem_is_purgeable(shmem);
> +	KUNIT_ASSERT_FALSE(test, ret);
> +
> +	ret = drm_gem_shmem_madvise(shmem, 1);
> +	KUNIT_ASSERT_TRUE(test, ret);
> +
> +	sgt = drm_gem_shmem_get_pages_sgt(shmem);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
> +
> +	ret = drm_gem_shmem_is_purgeable(shmem);
> +	KUNIT_ASSERT_TRUE(test, ret);
> +
> +	drm_gem_shmem_purge(shmem);
> +	KUNIT_ASSERT_TRUE(test, ret);
> +
> +	drm_gem_shmem_free(shmem);
> +}
> +
> +static int drm_gem_shmem_test_init(struct kunit *test)
> +{
> +	struct fake_dev *fdev;
> +	struct device *dev;
> +
> +	/* Allocate a parent device */
> +	dev = drm_kunit_helper_alloc_device(test);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
> +
> +	/*
> +	 * The DRM core will automatically initialize the GEM core and create
> +	 * a DRM Memory Manager object which provides an address space pool
> +	 * for GEM objects allocation.
> +	 */
> +	fdev = drm_kunit_helper_alloc_drm_device(test, dev, struct fake_dev,
> +						 drm_dev, DRIVER_GEM);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fdev);
> +
> +	fdev->dev = dev;
> +	test->priv = fdev;
> +
> +	return 0;
> +}
> +
> +static void drm_gem_shmem_test_exit(struct kunit *test)
> +{
> +	struct fake_dev *fdev = test->priv;
> +
> +	drm_kunit_helper_free_device(test, fdev->dev);
> +}

You don't need to call drm_kunit_helper_free_device() anymore

Maxime
Marco Pagani Oct. 24, 2023, 5:14 p.m. UTC | #2
On 2023-10-24 11:23, Maxime Ripard wrote:
> Hi Marco,
> 
> On Mon, Oct 23, 2023 at 06:45:40PM +0200, Marco Pagani wrote:
>> This patch introduces an initial KUnit test suite for GEM objects
>> backed by shmem buffers.
>>
>> Signed-off-by: Marco Pagani <marpagan@redhat.com>
>> ---
>>  drivers/gpu/drm/Kconfig                    |   1 +
>>  drivers/gpu/drm/tests/Makefile             |   3 +-
>>  drivers/gpu/drm/tests/drm_gem_shmem_test.c | 303 +++++++++++++++++++++
>>  3 files changed, 306 insertions(+), 1 deletion(-)
>>  create mode 100644 drivers/gpu/drm/tests/drm_gem_shmem_test.c
>>
>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>> index 3eee8636f847..f0a77e3e04d7 100644
>> --- a/drivers/gpu/drm/Kconfig
>> +++ b/drivers/gpu/drm/Kconfig
>> @@ -84,6 +84,7 @@ config DRM_KUNIT_TEST
>>  	select DRM_EXPORT_FOR_TESTS if m
>>  	select DRM_KUNIT_TEST_HELPERS
>>  	select DRM_EXEC
>> +	select DRM_GEM_SHMEM_HELPER
> 
> I know that DRM_EXEC already stands out, but these should be ordered
> alphabetically, so it should be before DRM_KUNIT_TEST_HELPERS.
> 
>>  	default KUNIT_ALL_TESTS
>>  	help
>>  	  This builds unit tests for DRM. This option is not useful for
>> diff --git a/drivers/gpu/drm/tests/Makefile b/drivers/gpu/drm/tests/Makefile
>> index ba7baa622675..b8227aab369e 100644
>> --- a/drivers/gpu/drm/tests/Makefile
>> +++ b/drivers/gpu/drm/tests/Makefile
>> @@ -18,6 +18,7 @@ obj-$(CONFIG_DRM_KUNIT_TEST) += \
>>  	drm_plane_helper_test.o \
>>  	drm_probe_helper_test.o \
>>  	drm_rect_test.o	\
>> -	drm_exec_test.o
>> +	drm_exec_test.o \
>> +	drm_gem_shmem_test.o
> 
> Ditto.
>

Right, I'll sort them alphabetically for v2.

>>  CFLAGS_drm_mm_test.o := $(DISABLE_STRUCTLEAK_PLUGIN)
>> diff --git a/drivers/gpu/drm/tests/drm_gem_shmem_test.c b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
>> new file mode 100644
>> index 000000000000..0bf6727f08d2
>> --- /dev/null
>> +++ b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
>> @@ -0,0 +1,303 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * KUnit test suite for GEM objects backed by shmem buffers
>> + *
>> + * Copyright (C) 2023 Red Hat, Inc.
>> + *
>> + * Author: Marco Pagani <marpagan@redhat.com>
>> + */
>> +
>> +#include <linux/dma-buf.h>
>> +#include <linux/iosys-map.h>
>> +#include <linux/sizes.h>
>> +
>> +#include <kunit/test.h>
>> +
>> +#include <drm/drm_device.h>
>> +#include <drm/drm_drv.h>
>> +#include <drm/drm_gem.h>
>> +#include <drm/drm_gem_shmem_helper.h>
>> +#include <drm/drm_kunit_helpers.h>
>> +
>> +#define TEST_SIZE		SZ_1M
>> +#define TEST_BYTE		0xae
>> +
>> +struct fake_dev {
>> +	struct drm_device drm_dev;
>> +	struct device *dev;
>> +};
>> +
>> +/* Test creating a shmem GEM object */
>> +static void drm_gem_shmem_test_obj_create(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev = test->priv;
>> +	struct drm_gem_shmem_object *shmem;
>> +
>> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
>> +	KUNIT_ASSERT_EQ(test, shmem->base.size, TEST_SIZE);
>> +	KUNIT_ASSERT_NOT_NULL(test, shmem->base.filp);
>> +	KUNIT_ASSERT_NOT_NULL(test, shmem->base.funcs);
>> +
>> +	drm_gem_shmem_free(shmem);
>> +}
>> +
>> +/* Test creating a private shmem GEM object from a scatter/gather table */
> 
> Thanks for documenting those tests. I believe we should also document
> what we expect from the test: should the test succeed? fail? if it
> fails, what is the cause of failure?
> 
> Based on the following test, I think something like the following would
> be good:
> 
> Test that creating a private shmem GEM object from a previously
> allocated sg_table succeeds and is properly initialized
> 
> Feel free to change it to something else if you find something missing.
>

Sounds good to me. I'll improve the documentation for v2.

>> +static void drm_gem_shmem_test_obj_create_private(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev = test->priv;
>> +	struct drm_gem_shmem_object *shmem;
>> +	struct drm_gem_object *gem_obj;
>> +	struct dma_buf buf_mock;
>> +	struct dma_buf_attachment attach_mock;
>> +	struct sg_table *sgt;
>> +	char *buf;
>> +	int ret;
>> +
>> +	/* Create a mock scatter/gather table */
>> +	buf = kunit_kzalloc(test, TEST_SIZE, GFP_KERNEL);
>> +	KUNIT_ASSERT_NOT_NULL(test, buf);
>> +
>> +	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
>> +	KUNIT_ASSERT_NOT_NULL(test, sgt);
>> +
>> +	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +	sg_init_one(sgt->sgl, buf, TEST_SIZE);
>> +
>> +	/* Init a mock DMA-BUF */
>> +	buf_mock.size = TEST_SIZE;
>> +	attach_mock.dmabuf = &buf_mock;
>> +
>> +	gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
>> +	KUNIT_ASSERT_EQ(test, gem_obj->size, TEST_SIZE);
>> +	KUNIT_ASSERT_NULL(test, gem_obj->filp);
>> +	KUNIT_ASSERT_NOT_NULL(test, gem_obj->funcs);
>> +
>> +	shmem = to_drm_gem_shmem_obj(gem_obj);
>> +	KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);
>> +
>> +	/* The scatter/gather table is freed by drm_gem_shmem_free */
>> +	drm_gem_shmem_free(shmem);
>> +}
> 
> KUNIT_ASSERT_* will stop the execution of the test on failure, you
> should probably use a bit more of KUNIT_EXPECT_* calls otherwise you'll
> leak resources.
> 
> You also probably want to use a kunit_action to clean up and avoid that
> whole discussion
>

You are right. I slightly prefer using KUnit expectations (unless actions
are strictly necessary) since I feel using actions makes test cases a bit
less straightforward to understand. Is this okay for you?

>> +
>> +/* Test pinning backing pages */
>> +static void drm_gem_shmem_test_pin_pages(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev = test->priv;
>> +	struct drm_gem_shmem_object *shmem;
>> +	int i, ret;
>> +
>> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
>> +	KUNIT_ASSERT_NULL(test, shmem->pages);
>> +	KUNIT_ASSERT_EQ(test, shmem->pages_use_count, 0);
>> +
>> +	ret = drm_gem_shmem_pin(shmem);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +	KUNIT_ASSERT_NOT_NULL(test, shmem->pages);
>> +	KUNIT_ASSERT_EQ(test, shmem->pages_use_count, 1);
>> +
>> +	for (i = 0; i < (shmem->base.size >> PAGE_SHIFT); i++)
>> +		KUNIT_ASSERT_NOT_NULL(test, shmem->pages[i]);
>> +
>> +	drm_gem_shmem_unpin(shmem);
>> +	KUNIT_ASSERT_NULL(test, shmem->pages);
>> +	KUNIT_ASSERT_EQ(test, shmem->pages_use_count, 0);
>> +
>> +	drm_gem_shmem_free(shmem);
>> +}
>> +
>> +/* Test creating a virtual mapping */
>> +static void drm_gem_shmem_test_vmap(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev = test->priv;
>> +	struct drm_gem_shmem_object *shmem;
>> +	struct iosys_map map;
>> +	int ret, i;
>> +
>> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
>> +	KUNIT_ASSERT_NULL(test, shmem->vaddr);
>> +	KUNIT_ASSERT_EQ(test, shmem->vmap_use_count, 0);
>> +
>> +	ret = drm_gem_shmem_vmap(shmem, &map);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +	KUNIT_ASSERT_NOT_NULL(test, shmem->vaddr);
>> +	KUNIT_ASSERT_EQ(test, shmem->vmap_use_count, 1);
>> +	KUNIT_ASSERT_FALSE(test, iosys_map_is_null(&map));
>> +
>> +	iosys_map_memset(&map, 0, TEST_BYTE, TEST_SIZE);
>> +	for (i = 0; i < TEST_SIZE; i++)
>> +		KUNIT_ASSERT_EQ(test, iosys_map_rd(&map, i, u8), TEST_BYTE);
>> +
>> +	drm_gem_shmem_vunmap(shmem, &map);
>> +	KUNIT_ASSERT_NULL(test, shmem->vaddr);
>> +	KUNIT_ASSERT_EQ(test, shmem->vmap_use_count, 0);
>> +
>> +	drm_gem_shmem_free(shmem);
>> +}
>> +
>> +/* Test exporting a scatter/gather table */
>> +static void drm_gem_shmem_test_get_pages_sgt(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev = test->priv;
>> +	struct drm_gem_shmem_object *shmem;
>> +	struct sg_table *sgt;
>> +	struct scatterlist *sg;
>> +	unsigned int si, len = 0;
>> +	int ret;
>> +
>> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
>> +
>> +	ret = drm_gem_shmem_pin(shmem);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	sgt = drm_gem_shmem_get_sg_table(shmem);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
>> +	KUNIT_ASSERT_NULL(test, shmem->sgt);
>> +
>> +	for_each_sgtable_sg(sgt, sg, si) {
>> +		KUNIT_ASSERT_NOT_NULL(test, sg);
>> +		len += sg->length;
>> +	}
>> +	KUNIT_ASSERT_GE(test, len, TEST_SIZE);
>> +
>> +	kfree(sgt);
>> +	drm_gem_shmem_free(shmem);
>> +}
>> +
>> +/* Test exporting a scatter/gather pinned table for PRIME */
>> +static void drm_gem_shmem_test_get_sg_table(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev = test->priv;
>> +	struct drm_gem_shmem_object *shmem;
>> +	struct sg_table *sgt;
>> +	struct scatterlist *sg;
>> +	unsigned int si, len = 0;
>> +
>> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
>> +
>> +	sgt = drm_gem_shmem_get_pages_sgt(shmem);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
>> +	KUNIT_ASSERT_PTR_EQ(test, sgt, shmem->sgt);
>> +
>> +	for_each_sgtable_sg(sgt, sg, si) {
>> +		KUNIT_ASSERT_NOT_NULL(test, sg);
>> +		len += sg->length;
>> +	}
>> +	KUNIT_ASSERT_GE(test, len, TEST_SIZE);
>> +
>> +	/* The scatter/gather table is freed by drm_gem_shmem_free */
>> +	drm_gem_shmem_free(shmem);
>> +}
>> +
>> +/* Test updating madvise status */
>> +static void drm_gem_shmem_test_madvise(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev = test->priv;
>> +	struct drm_gem_shmem_object *shmem;
>> +	int ret;
>> +
>> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
>> +	KUNIT_ASSERT_EQ(test, shmem->madv, 0);
>> +
>> +	ret = drm_gem_shmem_madvise(shmem, 1);
>> +	KUNIT_ASSERT_TRUE(test, ret);
>> +	KUNIT_ASSERT_EQ(test, shmem->madv, 1);
>> +
>> +	ret = drm_gem_shmem_madvise(shmem, -1);
>> +	KUNIT_ASSERT_FALSE(test, ret);
>> +	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
>> +
>> +	ret = drm_gem_shmem_madvise(shmem, 0);
>> +	KUNIT_ASSERT_FALSE(test, ret);
>> +	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
>> +
>> +	drm_gem_shmem_free(shmem);
>> +}
>> +
>> +/* Test purging */
>> +static void drm_gem_shmem_test_purge(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev = test->priv;
>> +	struct drm_gem_shmem_object *shmem;
>> +	struct sg_table *sgt;
>> +	int ret;
>> +
>> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
>> +
>> +	ret = drm_gem_shmem_is_purgeable(shmem);
>> +	KUNIT_ASSERT_FALSE(test, ret);
>> +
>> +	ret = drm_gem_shmem_madvise(shmem, 1);
>> +	KUNIT_ASSERT_TRUE(test, ret);
>> +
>> +	sgt = drm_gem_shmem_get_pages_sgt(shmem);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
>> +
>> +	ret = drm_gem_shmem_is_purgeable(shmem);
>> +	KUNIT_ASSERT_TRUE(test, ret);
>> +
>> +	drm_gem_shmem_purge(shmem);
>> +	KUNIT_ASSERT_TRUE(test, ret);
>> +
>> +	drm_gem_shmem_free(shmem);
>> +}
>> +
>> +static int drm_gem_shmem_test_init(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev;
>> +	struct device *dev;
>> +
>> +	/* Allocate a parent device */
>> +	dev = drm_kunit_helper_alloc_device(test);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
>> +
>> +	/*
>> +	 * The DRM core will automatically initialize the GEM core and create
>> +	 * a DRM Memory Manager object which provides an address space pool
>> +	 * for GEM objects allocation.
>> +	 */
>> +	fdev = drm_kunit_helper_alloc_drm_device(test, dev, struct fake_dev,
>> +						 drm_dev, DRIVER_GEM);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fdev);
>> +
>> +	fdev->dev = dev;
>> +	test->priv = fdev;
>> +
>> +	return 0;
>> +}
>> +
>> +static void drm_gem_shmem_test_exit(struct kunit *test)
>> +{
>> +	struct fake_dev *fdev = test->priv;
>> +
>> +	drm_kunit_helper_free_device(test, fdev->dev);
>> +}
> 
> You don't need to call drm_kunit_helper_free_device() anymore
> 
> Maxime

Right. Initially, I accidentally used an older tree that did not include
commit 4f2b0b583baa4. I'll remove the whole exit function for v2.


Thanks,
Marco
Maxime Ripard Oct. 25, 2023, 8:43 a.m. UTC | #3
Hi,

On Tue, Oct 24, 2023 at 07:14:25PM +0200, Marco Pagani wrote:
> >> +static void drm_gem_shmem_test_obj_create_private(struct kunit *test)
> >> +{
> >> +	struct fake_dev *fdev = test->priv;
> >> +	struct drm_gem_shmem_object *shmem;
> >> +	struct drm_gem_object *gem_obj;
> >> +	struct dma_buf buf_mock;
> >> +	struct dma_buf_attachment attach_mock;
> >> +	struct sg_table *sgt;
> >> +	char *buf;
> >> +	int ret;
> >> +
> >> +	/* Create a mock scatter/gather table */
> >> +	buf = kunit_kzalloc(test, TEST_SIZE, GFP_KERNEL);
> >> +	KUNIT_ASSERT_NOT_NULL(test, buf);
> >> +
> >> +	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> >> +	KUNIT_ASSERT_NOT_NULL(test, sgt);
> >> +
> >> +	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> >> +	KUNIT_ASSERT_EQ(test, ret, 0);
> >> +	sg_init_one(sgt->sgl, buf, TEST_SIZE);
> >> +
> >> +	/* Init a mock DMA-BUF */
> >> +	buf_mock.size = TEST_SIZE;
> >> +	attach_mock.dmabuf = &buf_mock;
> >> +
> >> +	gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
> >> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
> >> +	KUNIT_ASSERT_EQ(test, gem_obj->size, TEST_SIZE);
> >> +	KUNIT_ASSERT_NULL(test, gem_obj->filp);
> >> +	KUNIT_ASSERT_NOT_NULL(test, gem_obj->funcs);
> >> +
> >> +	shmem = to_drm_gem_shmem_obj(gem_obj);
> >> +	KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);
> >> +
> >> +	/* The scatter/gather table is freed by drm_gem_shmem_free */
> >> +	drm_gem_shmem_free(shmem);
> >> +}
> > 
> > KUNIT_ASSERT_* will stop the execution of the test on failure, you
> > should probably use a bit more of KUNIT_EXPECT_* calls otherwise you'll
> > leak resources.
> > 
> > You also probably want to use a kunit_action to clean up and avoid that
> > whole discussion
> >
> 
> You are right. I slightly prefer using KUnit expectations (unless actions
> are strictly necessary) since I feel using actions makes test cases a bit
> less straightforward to understand. Is this okay for you?

I disagree. Actions make it easier to reason about, even when comparing
assertion vs expectation

Like, for the call to sg_alloc_table and
drm_gem_shmem_prime_import_sg_table(), the reasonable use of assert vs
expect would be something like:

sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
KUNIT_ASSERT_NOT_NULL(test, sgt);

ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
KUNIT_ASSERT_EQ(test, ret, 0);

/*
 * Here, it's already not super clear whether you want to expect vs
 * assert. expect will make you handle the failure case later, assert will
 * force you to call kfree on sgt. Both kind of suck in their own ways.
 */

sg_init_one(sgt->sgl, buf, TEST_SIZE);

gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);

/*
 * If the assert fails, we forgot to call sg_free_table(sgt) and kfree(sgt).
 */

KUNIT_EXPECT_EQ(test, gem_obj->size, TEST_SIZE);
KUNIT_EXPECT_NULL(test, gem_obj->filp);
KUNIT_EXPECT_NOT_NULL(test, gem_obj->funcs);

/*
 * And here we have to handle the case where the expectation was wrong,
 * but the test still continued.
 */

But if you're not using an action, you still have to call kfree(sgt),
which means that you might still

shmem = to_drm_gem_shmem_obj(gem_obj);
KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);

/*
 * If the assertion fails, we now have to call drm_gem_shmem_free(shmem)
 */

/* The scatter/gather table is freed by drm_gem_shmem_free */
drm_gem_shmem_free(shmem);

/* everything's fine now */

The semantics around drm_gem_shmem_free make it a bit convoluted, but
doing it using goto/labels, plus handling the assertions and error
reporting would be difficult.

Using actions, we have:

sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
KUNIT_ASSERT_NOT_NULL(test, sgt);

ret = kunit_add_action_or_reset(test, kfree_wrapper, sgt);
KUNIT_ASSERT_EQ(test, ret, 0);

ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
KUNIT_ASSERT_EQ(test, ret, 0);

ret = kunit_add_action_or_reset(test, sg_free_table_wrapper, sgt);
KUNIT_ASSERT_EQ(test, ret, 0);

sg_init_one(sgt->sgl, buf, TEST_SIZE);

gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
KUNIT_EXPECT_EQ(test, gem_obj->size, TEST_SIZE);
KUNIT_EXPECT_NULL(test, gem_obj->filp);
KUNIT_EXPECT_NOT_NULL(test, gem_obj->funcs);

/* drm_gem_shmem_free will free the struct sg_table itself */
kunit_remove_action(test, sg_free_table_wrapper, sgt);
kunit_remove_action(test, kfree_wrapper, sgt);

shmem = to_drm_gem_shmem_obj(gem_obj);
KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);

ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
KUNIT_ASSERT_EQ(test, ret, 0);

The last one is arguable, but for the previous ones it makes error
handling much more convenient and easy to reason about.

The wrappers are also a bit inconvenient to use, but it's mostly there
to avoid a compiler warning at the moment.

This patch will help hopefully:
https://lore.kernel.org/linux-kselftest/20230915050125.3609689-1-davidgow@google.com/

Maxime
Marco Pagani Oct. 30, 2023, 10:58 a.m. UTC | #4
On 2023-10-25 10:43, Maxime Ripard wrote:
> Hi,
> 
> On Tue, Oct 24, 2023 at 07:14:25PM +0200, Marco Pagani wrote:
>>>> +static void drm_gem_shmem_test_obj_create_private(struct kunit *test)
>>>> +{
>>>> +	struct fake_dev *fdev = test->priv;
>>>> +	struct drm_gem_shmem_object *shmem;
>>>> +	struct drm_gem_object *gem_obj;
>>>> +	struct dma_buf buf_mock;
>>>> +	struct dma_buf_attachment attach_mock;
>>>> +	struct sg_table *sgt;
>>>> +	char *buf;
>>>> +	int ret;
>>>> +
>>>> +	/* Create a mock scatter/gather table */
>>>> +	buf = kunit_kzalloc(test, TEST_SIZE, GFP_KERNEL);
>>>> +	KUNIT_ASSERT_NOT_NULL(test, buf);
>>>> +
>>>> +	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
>>>> +	KUNIT_ASSERT_NOT_NULL(test, sgt);
>>>> +
>>>> +	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
>>>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>>>> +	sg_init_one(sgt->sgl, buf, TEST_SIZE);
>>>> +
>>>> +	/* Init a mock DMA-BUF */
>>>> +	buf_mock.size = TEST_SIZE;
>>>> +	attach_mock.dmabuf = &buf_mock;
>>>> +
>>>> +	gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
>>>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
>>>> +	KUNIT_ASSERT_EQ(test, gem_obj->size, TEST_SIZE);
>>>> +	KUNIT_ASSERT_NULL(test, gem_obj->filp);
>>>> +	KUNIT_ASSERT_NOT_NULL(test, gem_obj->funcs);
>>>> +
>>>> +	shmem = to_drm_gem_shmem_obj(gem_obj);
>>>> +	KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);
>>>> +
>>>> +	/* The scatter/gather table is freed by drm_gem_shmem_free */
>>>> +	drm_gem_shmem_free(shmem);
>>>> +}
>>>
>>> KUNIT_ASSERT_* will stop the execution of the test on failure, you
>>> should probably use a bit more of KUNIT_EXPECT_* calls otherwise you'll
>>> leak resources.
>>>
>>> You also probably want to use a kunit_action to clean up and avoid that
>>> whole discussion
>>>
>>
>> You are right. I slightly prefer using KUnit expectations (unless actions
>> are strictly necessary) since I feel using actions makes test cases a bit
>> less straightforward to understand. Is this okay for you?
> 
> I disagree. Actions make it easier to reason about, even when comparing
> assertion vs expectation
> 
> Like, for the call to sg_alloc_table and
> drm_gem_shmem_prime_import_sg_table(), the reasonable use of assert vs
> expect would be something like:
> 
> sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> KUNIT_ASSERT_NOT_NULL(test, sgt);
> 
> ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> KUNIT_ASSERT_EQ(test, ret, 0);
> 
> /*
>  * Here, it's already not super clear whether you want to expect vs
>  * assert. expect will make you handle the failure case later, assert will
>  * force you to call kfree on sgt. Both kind of suck in their own ways.
>  */
> 
> sg_init_one(sgt->sgl, buf, TEST_SIZE);
> 
> gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
> 
> /*
>  * If the assert fails, we forgot to call sg_free_table(sgt) and kfree(sgt).
>  */
> 
> KUNIT_EXPECT_EQ(test, gem_obj->size, TEST_SIZE);
> KUNIT_EXPECT_NULL(test, gem_obj->filp);
> KUNIT_EXPECT_NOT_NULL(test, gem_obj->funcs);
> 
> /*
>  * And here we have to handle the case where the expectation was wrong,
>  * but the test still continued.
>  */
> 
> But if you're not using an action, you still have to call kfree(sgt),
> which means that you might still
> 
> shmem = to_drm_gem_shmem_obj(gem_obj);
> KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);
> 
> /*
>  * If the assertion fails, we now have to call drm_gem_shmem_free(shmem)
>  */
> 
> /* The scatter/gather table is freed by drm_gem_shmem_free */
> drm_gem_shmem_free(shmem);
> 
> /* everything's fine now */
> 
> The semantics around drm_gem_shmem_free make it a bit convoluted, but
> doing it using goto/labels, plus handling the assertions and error
> reporting would be difficult.
> 
> Using actions, we have:
> 
> sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> KUNIT_ASSERT_NOT_NULL(test, sgt);
> 
> ret = kunit_add_action_or_reset(test, kfree_wrapper, sgt);
> KUNIT_ASSERT_EQ(test, ret, 0);
> 
> ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> KUNIT_ASSERT_EQ(test, ret, 0);
> 
> ret = kunit_add_action_or_reset(test, sg_free_table_wrapper, sgt);
> KUNIT_ASSERT_EQ(test, ret, 0);
> 
> sg_init_one(sgt->sgl, buf, TEST_SIZE);
> 
> gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
> KUNIT_EXPECT_EQ(test, gem_obj->size, TEST_SIZE);
> KUNIT_EXPECT_NULL(test, gem_obj->filp);
> KUNIT_EXPECT_NOT_NULL(test, gem_obj->funcs);
> 
> /* drm_gem_shmem_free will free the struct sg_table itself */
> kunit_remove_action(test, sg_free_table_wrapper, sgt);
> kunit_remove_action(test, kfree_wrapper, sgt);

I agree that using actions makes error handling cleaner. However, I still
have some concerns about the additional complexity that actions introduce.
For instance, I feel these two lines make the testing harness more complex
without asserting any additional property of the component under test. 

In some sense, I wonder if it is worth worrying about memory leaks when
a test case fails. At that point, the system is already in an inconsistent
state due to a bug in the component under test, so it is unsafe to continue
anyway.

> 
> shmem = to_drm_gem_shmem_obj(gem_obj);
> KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);
> 
> ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
> KUNIT_ASSERT_EQ(test, ret, 0);
> 
> The last one is arguable, but for the previous ones it makes error
> handling much more convenient and easy to reason about.
> 
> The wrappers are also a bit inconvenient to use, but it's mostly there
> to avoid a compiler warning at the moment.
> 
> This patch will help hopefully:
> https://lore.kernel.org/linux-kselftest/20230915050125.3609689-1-davidgow@google.com/
> 
> Maxime

Thanks,
Marco
Maxime Ripard Nov. 6, 2023, 1:46 p.m. UTC | #5
On Mon, Oct 30, 2023 at 11:58:20AM +0100, Marco Pagani wrote:
> On 2023-10-25 10:43, Maxime Ripard wrote:
> > On Tue, Oct 24, 2023 at 07:14:25PM +0200, Marco Pagani wrote:
> >>>> +static void drm_gem_shmem_test_obj_create_private(struct kunit *test)
> >>>> +{
> >>>> +	struct fake_dev *fdev = test->priv;
> >>>> +	struct drm_gem_shmem_object *shmem;
> >>>> +	struct drm_gem_object *gem_obj;
> >>>> +	struct dma_buf buf_mock;
> >>>> +	struct dma_buf_attachment attach_mock;
> >>>> +	struct sg_table *sgt;
> >>>> +	char *buf;
> >>>> +	int ret;
> >>>> +
> >>>> +	/* Create a mock scatter/gather table */
> >>>> +	buf = kunit_kzalloc(test, TEST_SIZE, GFP_KERNEL);
> >>>> +	KUNIT_ASSERT_NOT_NULL(test, buf);
> >>>> +
> >>>> +	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> >>>> +	KUNIT_ASSERT_NOT_NULL(test, sgt);
> >>>> +
> >>>> +	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> >>>> +	KUNIT_ASSERT_EQ(test, ret, 0);
> >>>> +	sg_init_one(sgt->sgl, buf, TEST_SIZE);
> >>>> +
> >>>> +	/* Init a mock DMA-BUF */
> >>>> +	buf_mock.size = TEST_SIZE;
> >>>> +	attach_mock.dmabuf = &buf_mock;
> >>>> +
> >>>> +	gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
> >>>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
> >>>> +	KUNIT_ASSERT_EQ(test, gem_obj->size, TEST_SIZE);
> >>>> +	KUNIT_ASSERT_NULL(test, gem_obj->filp);
> >>>> +	KUNIT_ASSERT_NOT_NULL(test, gem_obj->funcs);
> >>>> +
> >>>> +	shmem = to_drm_gem_shmem_obj(gem_obj);
> >>>> +	KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);
> >>>> +
> >>>> +	/* The scatter/gather table is freed by drm_gem_shmem_free */
> >>>> +	drm_gem_shmem_free(shmem);
> >>>> +}
> >>>
> >>> KUNIT_ASSERT_* will stop the execution of the test on failure, you
> >>> should probably use a bit more of KUNIT_EXPECT_* calls otherwise you'll
> >>> leak resources.
> >>>
> >>> You also probably want to use a kunit_action to clean up and avoid that
> >>> whole discussion
> >>>
> >>
> >> You are right. I slightly prefer using KUnit expectations (unless actions
> >> are strictly necessary) since I feel using actions makes test cases a bit
> >> less straightforward to understand. Is this okay for you?
> > 
> > I disagree. Actions make it easier to reason about, even when comparing
> > assertion vs expectation
> > 
> > Like, for the call to sg_alloc_table and
> > drm_gem_shmem_prime_import_sg_table(), the reasonable use of assert vs
> > expect would be something like:
> > 
> > sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> > KUNIT_ASSERT_NOT_NULL(test, sgt);
> > 
> > ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> > KUNIT_ASSERT_EQ(test, ret, 0);
> > 
> > /*
> >  * Here, it's already not super clear whether you want to expect vs
> >  * assert. expect will make you handle the failure case later, assert will
> >  * force you to call kfree on sgt. Both kind of suck in their own ways.
> >  */
> > 
> > sg_init_one(sgt->sgl, buf, TEST_SIZE);
> > 
> > gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
> > KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
> > 
> > /*
> >  * If the assert fails, we forgot to call sg_free_table(sgt) and kfree(sgt).
> >  */
> > 
> > KUNIT_EXPECT_EQ(test, gem_obj->size, TEST_SIZE);
> > KUNIT_EXPECT_NULL(test, gem_obj->filp);
> > KUNIT_EXPECT_NOT_NULL(test, gem_obj->funcs);
> > 
> > /*
> >  * And here we have to handle the case where the expectation was wrong,
> >  * but the test still continued.
> >  */
> > 
> > But if you're not using an action, you still have to call kfree(sgt),
> > which means that you might still
> > 
> > shmem = to_drm_gem_shmem_obj(gem_obj);
> > KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);
> > 
> > /*
> >  * If the assertion fails, we now have to call drm_gem_shmem_free(shmem)
> >  */
> > 
> > /* The scatter/gather table is freed by drm_gem_shmem_free */
> > drm_gem_shmem_free(shmem);
> > 
> > /* everything's fine now */
> > 
> > The semantics around drm_gem_shmem_free make it a bit convoluted, but
> > doing it using goto/labels, plus handling the assertions and error
> > reporting would be difficult.
> > 
> > Using actions, we have:
> > 
> > sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> > KUNIT_ASSERT_NOT_NULL(test, sgt);
> > 
> > ret = kunit_add_action_or_reset(test, kfree_wrapper, sgt);
> > KUNIT_ASSERT_EQ(test, ret, 0);
> > 
> > ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> > KUNIT_ASSERT_EQ(test, ret, 0);
> > 
> > ret = kunit_add_action_or_reset(test, sg_free_table_wrapper, sgt);
> > KUNIT_ASSERT_EQ(test, ret, 0);
> > 
> > sg_init_one(sgt->sgl, buf, TEST_SIZE);
> > 
> > gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
> > KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
> > KUNIT_EXPECT_EQ(test, gem_obj->size, TEST_SIZE);
> > KUNIT_EXPECT_NULL(test, gem_obj->filp);
> > KUNIT_EXPECT_NOT_NULL(test, gem_obj->funcs);
> > 
> > /* drm_gem_shmem_free will free the struct sg_table itself */
> > kunit_remove_action(test, sg_free_table_wrapper, sgt);
> > kunit_remove_action(test, kfree_wrapper, sgt);
> 
> I agree that using actions makes error handling cleaner. However, I still
> have some concerns about the additional complexity that actions introduce.
> For instance, I feel these two lines make the testing harness more complex
> without asserting any additional property of the component under test. 

If anything, the API makes it more difficult to deal with. It would
actually be harder/messier to handle without an action.

> In some sense, I wonder if it is worth worrying about memory leaks when
> a test case fails. At that point, the system is already in an inconsistent
> state due to a bug in the component under test, so it is unsafe to continue
> anyway.

I guess the larger issue is: once that code will be merged, we're going
to have patches to convert to actions because they make it nicer and fix
a couple of issues anyway.

So, if it's still the state we're going to end up in, why not doing it
right from the beginning?

Maxime
diff mbox series

Patch

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 3eee8636f847..f0a77e3e04d7 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -84,6 +84,7 @@  config DRM_KUNIT_TEST
 	select DRM_EXPORT_FOR_TESTS if m
 	select DRM_KUNIT_TEST_HELPERS
 	select DRM_EXEC
+	select DRM_GEM_SHMEM_HELPER
 	default KUNIT_ALL_TESTS
 	help
 	  This builds unit tests for DRM. This option is not useful for
diff --git a/drivers/gpu/drm/tests/Makefile b/drivers/gpu/drm/tests/Makefile
index ba7baa622675..b8227aab369e 100644
--- a/drivers/gpu/drm/tests/Makefile
+++ b/drivers/gpu/drm/tests/Makefile
@@ -18,6 +18,7 @@  obj-$(CONFIG_DRM_KUNIT_TEST) += \
 	drm_plane_helper_test.o \
 	drm_probe_helper_test.o \
 	drm_rect_test.o	\
-	drm_exec_test.o
+	drm_exec_test.o \
+	drm_gem_shmem_test.o
 
 CFLAGS_drm_mm_test.o := $(DISABLE_STRUCTLEAK_PLUGIN)
diff --git a/drivers/gpu/drm/tests/drm_gem_shmem_test.c b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
new file mode 100644
index 000000000000..0bf6727f08d2
--- /dev/null
+++ b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
@@ -0,0 +1,303 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit test suite for GEM objects backed by shmem buffers
+ *
+ * Copyright (C) 2023 Red Hat, Inc.
+ *
+ * Author: Marco Pagani <marpagan@redhat.com>
+ */
+
+#include <linux/dma-buf.h>
+#include <linux/iosys-map.h>
+#include <linux/sizes.h>
+
+#include <kunit/test.h>
+
+#include <drm/drm_device.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_gem.h>
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_kunit_helpers.h>
+
+#define TEST_SIZE		SZ_1M
+#define TEST_BYTE		0xae
+
+struct fake_dev {
+	struct drm_device drm_dev;
+	struct device *dev;
+};
+
+/* Test creating a shmem GEM object */
+static void drm_gem_shmem_test_obj_create(struct kunit *test)
+{
+	struct fake_dev *fdev = test->priv;
+	struct drm_gem_shmem_object *shmem;
+
+	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
+	KUNIT_ASSERT_EQ(test, shmem->base.size, TEST_SIZE);
+	KUNIT_ASSERT_NOT_NULL(test, shmem->base.filp);
+	KUNIT_ASSERT_NOT_NULL(test, shmem->base.funcs);
+
+	drm_gem_shmem_free(shmem);
+}
+
+/* Test creating a private shmem GEM object from a scatter/gather table */
+static void drm_gem_shmem_test_obj_create_private(struct kunit *test)
+{
+	struct fake_dev *fdev = test->priv;
+	struct drm_gem_shmem_object *shmem;
+	struct drm_gem_object *gem_obj;
+	struct dma_buf buf_mock;
+	struct dma_buf_attachment attach_mock;
+	struct sg_table *sgt;
+	char *buf;
+	int ret;
+
+	/* Create a mock scatter/gather table */
+	buf = kunit_kzalloc(test, TEST_SIZE, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, buf);
+
+	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, sgt);
+
+	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+	sg_init_one(sgt->sgl, buf, TEST_SIZE);
+
+	/* Init a mock DMA-BUF */
+	buf_mock.size = TEST_SIZE;
+	attach_mock.dmabuf = &buf_mock;
+
+	gem_obj = drm_gem_shmem_prime_import_sg_table(&fdev->drm_dev, &attach_mock, sgt);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gem_obj);
+	KUNIT_ASSERT_EQ(test, gem_obj->size, TEST_SIZE);
+	KUNIT_ASSERT_NULL(test, gem_obj->filp);
+	KUNIT_ASSERT_NOT_NULL(test, gem_obj->funcs);
+
+	shmem = to_drm_gem_shmem_obj(gem_obj);
+	KUNIT_ASSERT_PTR_EQ(test, shmem->sgt, sgt);
+
+	/* The scatter/gather table is freed by drm_gem_shmem_free */
+	drm_gem_shmem_free(shmem);
+}
+
+/* Test pinning backing pages */
+static void drm_gem_shmem_test_pin_pages(struct kunit *test)
+{
+	struct fake_dev *fdev = test->priv;
+	struct drm_gem_shmem_object *shmem;
+	int i, ret;
+
+	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
+	KUNIT_ASSERT_NULL(test, shmem->pages);
+	KUNIT_ASSERT_EQ(test, shmem->pages_use_count, 0);
+
+	ret = drm_gem_shmem_pin(shmem);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+	KUNIT_ASSERT_NOT_NULL(test, shmem->pages);
+	KUNIT_ASSERT_EQ(test, shmem->pages_use_count, 1);
+
+	for (i = 0; i < (shmem->base.size >> PAGE_SHIFT); i++)
+		KUNIT_ASSERT_NOT_NULL(test, shmem->pages[i]);
+
+	drm_gem_shmem_unpin(shmem);
+	KUNIT_ASSERT_NULL(test, shmem->pages);
+	KUNIT_ASSERT_EQ(test, shmem->pages_use_count, 0);
+
+	drm_gem_shmem_free(shmem);
+}
+
+/* Test creating a virtual mapping */
+static void drm_gem_shmem_test_vmap(struct kunit *test)
+{
+	struct fake_dev *fdev = test->priv;
+	struct drm_gem_shmem_object *shmem;
+	struct iosys_map map;
+	int ret, i;
+
+	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
+	KUNIT_ASSERT_NULL(test, shmem->vaddr);
+	KUNIT_ASSERT_EQ(test, shmem->vmap_use_count, 0);
+
+	ret = drm_gem_shmem_vmap(shmem, &map);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+	KUNIT_ASSERT_NOT_NULL(test, shmem->vaddr);
+	KUNIT_ASSERT_EQ(test, shmem->vmap_use_count, 1);
+	KUNIT_ASSERT_FALSE(test, iosys_map_is_null(&map));
+
+	iosys_map_memset(&map, 0, TEST_BYTE, TEST_SIZE);
+	for (i = 0; i < TEST_SIZE; i++)
+		KUNIT_ASSERT_EQ(test, iosys_map_rd(&map, i, u8), TEST_BYTE);
+
+	drm_gem_shmem_vunmap(shmem, &map);
+	KUNIT_ASSERT_NULL(test, shmem->vaddr);
+	KUNIT_ASSERT_EQ(test, shmem->vmap_use_count, 0);
+
+	drm_gem_shmem_free(shmem);
+}
+
+/* Test exporting a scatter/gather table */
+static void drm_gem_shmem_test_get_pages_sgt(struct kunit *test)
+{
+	struct fake_dev *fdev = test->priv;
+	struct drm_gem_shmem_object *shmem;
+	struct sg_table *sgt;
+	struct scatterlist *sg;
+	unsigned int si, len = 0;
+	int ret;
+
+	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
+
+	ret = drm_gem_shmem_pin(shmem);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	sgt = drm_gem_shmem_get_sg_table(shmem);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
+	KUNIT_ASSERT_NULL(test, shmem->sgt);
+
+	for_each_sgtable_sg(sgt, sg, si) {
+		KUNIT_ASSERT_NOT_NULL(test, sg);
+		len += sg->length;
+	}
+	KUNIT_ASSERT_GE(test, len, TEST_SIZE);
+
+	kfree(sgt);
+	drm_gem_shmem_free(shmem);
+}
+
+/* Test exporting a scatter/gather pinned table for PRIME */
+static void drm_gem_shmem_test_get_sg_table(struct kunit *test)
+{
+	struct fake_dev *fdev = test->priv;
+	struct drm_gem_shmem_object *shmem;
+	struct sg_table *sgt;
+	struct scatterlist *sg;
+	unsigned int si, len = 0;
+
+	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
+
+	sgt = drm_gem_shmem_get_pages_sgt(shmem);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
+	KUNIT_ASSERT_PTR_EQ(test, sgt, shmem->sgt);
+
+	for_each_sgtable_sg(sgt, sg, si) {
+		KUNIT_ASSERT_NOT_NULL(test, sg);
+		len += sg->length;
+	}
+	KUNIT_ASSERT_GE(test, len, TEST_SIZE);
+
+	/* The scatter/gather table is freed by drm_gem_shmem_free */
+	drm_gem_shmem_free(shmem);
+}
+
+/* Test updating madvise status */
+static void drm_gem_shmem_test_madvise(struct kunit *test)
+{
+	struct fake_dev *fdev = test->priv;
+	struct drm_gem_shmem_object *shmem;
+	int ret;
+
+	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
+	KUNIT_ASSERT_EQ(test, shmem->madv, 0);
+
+	ret = drm_gem_shmem_madvise(shmem, 1);
+	KUNIT_ASSERT_TRUE(test, ret);
+	KUNIT_ASSERT_EQ(test, shmem->madv, 1);
+
+	ret = drm_gem_shmem_madvise(shmem, -1);
+	KUNIT_ASSERT_FALSE(test, ret);
+	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
+
+	ret = drm_gem_shmem_madvise(shmem, 0);
+	KUNIT_ASSERT_FALSE(test, ret);
+	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
+
+	drm_gem_shmem_free(shmem);
+}
+
+/* Test purging */
+static void drm_gem_shmem_test_purge(struct kunit *test)
+{
+	struct fake_dev *fdev = test->priv;
+	struct drm_gem_shmem_object *shmem;
+	struct sg_table *sgt;
+	int ret;
+
+	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
+
+	ret = drm_gem_shmem_is_purgeable(shmem);
+	KUNIT_ASSERT_FALSE(test, ret);
+
+	ret = drm_gem_shmem_madvise(shmem, 1);
+	KUNIT_ASSERT_TRUE(test, ret);
+
+	sgt = drm_gem_shmem_get_pages_sgt(shmem);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
+
+	ret = drm_gem_shmem_is_purgeable(shmem);
+	KUNIT_ASSERT_TRUE(test, ret);
+
+	drm_gem_shmem_purge(shmem);
+	KUNIT_ASSERT_TRUE(test, ret);
+
+	drm_gem_shmem_free(shmem);
+}
+
+static int drm_gem_shmem_test_init(struct kunit *test)
+{
+	struct fake_dev *fdev;
+	struct device *dev;
+
+	/* Allocate a parent device */
+	dev = drm_kunit_helper_alloc_device(test);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
+
+	/*
+	 * The DRM core will automatically initialize the GEM core and create
+	 * a DRM Memory Manager object which provides an address space pool
+	 * for GEM objects allocation.
+	 */
+	fdev = drm_kunit_helper_alloc_drm_device(test, dev, struct fake_dev,
+						 drm_dev, DRIVER_GEM);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fdev);
+
+	fdev->dev = dev;
+	test->priv = fdev;
+
+	return 0;
+}
+
+static void drm_gem_shmem_test_exit(struct kunit *test)
+{
+	struct fake_dev *fdev = test->priv;
+
+	drm_kunit_helper_free_device(test, fdev->dev);
+}
+
+static struct kunit_case drm_gem_shmem_test_cases[] = {
+	KUNIT_CASE(drm_gem_shmem_test_obj_create),
+	KUNIT_CASE(drm_gem_shmem_test_obj_create_private),
+	KUNIT_CASE(drm_gem_shmem_test_pin_pages),
+	KUNIT_CASE(drm_gem_shmem_test_vmap),
+	KUNIT_CASE(drm_gem_shmem_test_get_pages_sgt),
+	KUNIT_CASE(drm_gem_shmem_test_get_sg_table),
+	KUNIT_CASE(drm_gem_shmem_test_madvise),
+	KUNIT_CASE(drm_gem_shmem_test_purge),
+	{}
+};
+
+static struct kunit_suite drm_gem_shmem_suite = {
+	.name = "drm_gem_shmem",
+	.init = drm_gem_shmem_test_init,
+	.exit = drm_gem_shmem_test_exit,
+	.test_cases = drm_gem_shmem_test_cases
+};
+
+kunit_test_suite(drm_gem_shmem_suite);