[RFC,v2] drm/test: add a test suite for GEM objects backed by shmem

  This patch introduces an initial KUnit test suite for GEM objects
backed by shmem buffers.

Suggested-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Marco Pagani <marpagan@redhat.com>

v2:
- Improved description of test cases
- Cleaner error handling using KUnit actions
- Alphabetical order in Kconfig and Makefile
---
 drivers/gpu/drm/Kconfig                    |   9 +-
 drivers/gpu/drm/tests/Makefile             |   5 +-
 drivers/gpu/drm/tests/drm_gem_shmem_test.c | 381 +++++++++++++++++++++
 3 files changed, 389 insertions(+), 6 deletions(-)
 create mode 100644 drivers/gpu/drm/tests/drm_gem_shmem_test.c


base-commit: 9ccde17d46554dbb2757c427f2cdf67688701f96
  

On Wed, Nov 08, 2023 at 02:42:03PM +0100, Marco Pagani wrote:
> This patch introduces an initial KUnit test suite for GEM objects
> backed by shmem buffers.
> 
> Suggested-by: Javier Martinez Canillas <javierm@redhat.com>
> Signed-off-by: Marco Pagani <marpagan@redhat.com>
> 
> v2:
> - Improved description of test cases
> - Cleaner error handling using KUnit actions
> - Alphabetical order in Kconfig and Makefile
> ---
>  drivers/gpu/drm/Kconfig                    |   9 +-
>  drivers/gpu/drm/tests/Makefile             |   5 +-
>  drivers/gpu/drm/tests/drm_gem_shmem_test.c | 381 +++++++++++++++++++++
>  3 files changed, 389 insertions(+), 6 deletions(-)
>  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..a2551c8c393a 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -76,14 +76,15 @@ config DRM_KUNIT_TEST
>  	tristate "KUnit tests for DRM" if !KUNIT_ALL_TESTS
>  	depends on DRM && KUNIT
>  	select PRIME_NUMBERS
> +	select DRM_BUDDY
>  	select DRM_DISPLAY_DP_HELPER
>  	select DRM_DISPLAY_HELPER
> -	select DRM_LIB_RANDOM
> -	select DRM_KMS_HELPER
> -	select DRM_BUDDY
> +	select DRM_EXEC
>  	select DRM_EXPORT_FOR_TESTS if m
> +	select DRM_GEM_SHMEM_HELPER
> +	select DRM_KMS_HELPER
>  	select DRM_KUNIT_TEST_HELPERS
> -	select DRM_EXEC
> +	select DRM_LIB_RANDOM
>  	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..d6183b3d7688 100644
> --- a/drivers/gpu/drm/tests/Makefile
> +++ b/drivers/gpu/drm/tests/Makefile
> @@ -9,15 +9,16 @@ obj-$(CONFIG_DRM_KUNIT_TEST) += \
>  	drm_connector_test.o \
>  	drm_damage_helper_test.o \
>  	drm_dp_mst_helper_test.o \
> +	drm_exec_test.o \
>  	drm_format_helper_test.o \
>  	drm_format_test.o \
>  	drm_framebuffer_test.o \
> +	drm_gem_shmem_test.o \
>  	drm_managed_test.o \
>  	drm_mm_test.o \
>  	drm_modes_test.o \
>  	drm_plane_helper_test.o \
>  	drm_probe_helper_test.o \
> -	drm_rect_test.o	\
> -	drm_exec_test.o
> +	drm_rect_test.o

Thanks for reordering the tests and symbols, but they should part of a
preliminary patch.

>  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..983380490673
> --- /dev/null
> +++ b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
> @@ -0,0 +1,381 @@
> +// 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;

AFAICS, you're not using the dev pointer anywhere. You could remove the
fake_dev struct entirely and pass the drm_device pointer in test->priv

> +};
> +
> +/*
> + * Wrappers to avoid an explicit type casting when passing action
> + * functions to kunit_add_action().
> + */
> +static void kfree_wrapper(void *p)
> +{
> +	kfree(p);
> +}
> +
> +static void sg_free_table_wrapper(void *sgt)
> +{
> +	sg_free_table(sgt);
> +}
> +
> +static void drm_gem_shmem_free_wrapper(void *shmem)
> +{
> +	drm_gem_shmem_free(shmem);
> +}

I think you need to explicitly cast the pointer (or do a temporary
assignment to the proper type) to avoid a compiler warning.

> +/*
> + * Test creating a shmem GEM object backed by shmem buffer. The test
> + * case succeeds if the GEM object is successfully allocated with the
> + * shmem file node and object functions attributes set, and the size
> + * attribute is equal to the correct size.
> + */

Thanks for all those comments, it's super helpful

> +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_EXPECT_EQ(test, shmem->base.size, TEST_SIZE);
> +	KUNIT_EXPECT_NOT_NULL(test, shmem->base.filp);
> +	KUNIT_EXPECT_NOT_NULL(test, shmem->base.funcs);
> +
> +	drm_gem_shmem_free(shmem);
> +}
> +
> +/*
> + * Test creating a shmem GEM object from a scatter/gather table exported
> + * via a DMA-BUF. The test case succeed if the GEM object is successfully
> + * created with the shmem file node attribute equal to NULL and the sgt
> + * attribute pointing to the scatter/gather table that has been imported.
> + */
> +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 = 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);
> +
> +	/* 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_EXPECT_EQ(test, gem_obj->size, TEST_SIZE);
> +	KUNIT_EXPECT_NULL(test, gem_obj->filp);
> +	KUNIT_EXPECT_NOT_NULL(test, gem_obj->funcs);
> +
> +	/* The scatter/gather table will be freed by drm_gem_shmem_free */
> +	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_EXPECT_PTR_EQ(test, shmem->sgt, sgt);
> +
> +	drm_gem_shmem_free(shmem);
> +}
> +
> +/*
> + * Test pinning backing pages for a shmem GEM object. The test case
> + * succeeds if a suitable number of backing pages are allocated, and
> + * the pages table counter attribute is increased by one.
> + */
> +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_EXPECT_NULL(test, shmem->pages);
> +	KUNIT_EXPECT_EQ(test, shmem->pages_use_count, 0);
> +
> +	ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	ret = drm_gem_shmem_pin(shmem);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +	KUNIT_ASSERT_NOT_NULL(test, shmem->pages);
> +	KUNIT_EXPECT_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_EXPECT_NULL(test, shmem->pages);
> +	KUNIT_EXPECT_EQ(test, shmem->pages_use_count, 0);
> +}
> +
> +/*
> + * Test creating a virtual mapping for a shmem GEM object. The test
> + * case succeeds if the backing memory is mapped and the reference
> + * counter for virtual mapping is increased by one. Moreover, the test
> + * case writes and then reads a test pattern over the mapped memory.
> + */
> +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_EXPECT_NULL(test, shmem->vaddr);
> +	KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 0);
> +
> +	ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	ret = drm_gem_shmem_vmap(shmem, &map);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +	KUNIT_ASSERT_NOT_NULL(test, shmem->vaddr);
> +	KUNIT_ASSERT_FALSE(test, iosys_map_is_null(&map));
> +	KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 1);
> +
> +	iosys_map_memset(&map, 0, TEST_BYTE, TEST_SIZE);
> +	for (i = 0; i < TEST_SIZE; i++)
> +		KUNIT_EXPECT_EQ(test, iosys_map_rd(&map, i, u8), TEST_BYTE);
> +
> +	drm_gem_shmem_vunmap(shmem, &map);
> +	KUNIT_EXPECT_NULL(test, shmem->vaddr);
> +	KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 0);
> +}
> +
> +/*
> + * Test exporting a scatter/gather table of pinned pages suitable for
> + * PRIME usage from a shmem GEM object. The test case succeeds if a
> + * scatter/gather table large enough to accommodate the backing memory
> + * is successfully exported.
> + */
> +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 = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	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_EXPECT_NULL(test, shmem->sgt);
> +
> +	ret = kunit_add_action_or_reset(test, sg_free_table_wrapper, sgt);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	for_each_sgtable_sg(sgt, sg, si) {
> +		KUNIT_EXPECT_NOT_NULL(test, sg);
> +		len += sg->length;
> +	}
> +
> +	KUNIT_EXPECT_GE(test, len, TEST_SIZE);
> +}
> +
> +/*
> + * Test pinning pages and exporting a scatter/gather table suitable for
> + * driver usage from a shmem GEM object. The test case succeeds if the
> + * backing pages are pinned and a scatter/gather table large enough to
> + * accommodate the backing memory is successfully exported.
> + */
> +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, ret = 0;
> +
> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
> +
> +	ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	/* The scatter/gather table will be freed by drm_gem_shmem_free */
> +	sgt = drm_gem_shmem_get_pages_sgt(shmem);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
> +	KUNIT_ASSERT_NOT_NULL(test, shmem->pages);
> +	KUNIT_EXPECT_EQ(test, shmem->pages_use_count, 1);
> +	KUNIT_EXPECT_PTR_EQ(test, sgt, shmem->sgt);
> +
> +	for_each_sgtable_sg(sgt, sg, si) {
> +		KUNIT_EXPECT_NOT_NULL(test, sg);
> +		len += sg->length;
> +	}
> +
> +	KUNIT_EXPECT_GE(test, len, TEST_SIZE);
> +}
> +
> +/*
> + * Test updating the madvise state of a shmem GEM object. The test
> + * case checks that the function for setting madv updates it only if
> + * its current value is greater or equal than zero and returns false
> + * if it has a negative value.
> + */
> +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 = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	ret = drm_gem_shmem_madvise(shmem, 1);
> +	KUNIT_EXPECT_TRUE(test, ret);
> +	KUNIT_ASSERT_EQ(test, shmem->madv, 1);
> +
> +	/* Set madv to a negative value */
> +	ret = drm_gem_shmem_madvise(shmem, -1);
> +	KUNIT_EXPECT_FALSE(test, ret);
> +	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
> +
> +	/* Check that madv cannot be set back to a positive value */
> +	ret = drm_gem_shmem_madvise(shmem, 0);
> +	KUNIT_EXPECT_FALSE(test, ret);
> +	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
> +}
> +
> +/*
> + * Test purging a shmem GEM object. First, assert that a newly created
> + * shmem GEM object is not purgeable. Then, set madvise to a positive
> + * value and call drm_gem_shmem_get_pages_sgt() to pin and dma-map the
> + * backing pages. Finally, assert that the shmem GEM object is now
> + * purgeable and purge it.
> + */
> +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 = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	ret = drm_gem_shmem_is_purgeable(shmem);
> +	KUNIT_EXPECT_FALSE(test, ret);
> +
> +	ret = drm_gem_shmem_madvise(shmem, 1);
> +	KUNIT_EXPECT_TRUE(test, ret);
> +
> +	/* The scatter/gather table will be freed by drm_gem_shmem_free */
> +	sgt = drm_gem_shmem_get_pages_sgt(shmem);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
> +
> +	ret = drm_gem_shmem_is_purgeable(shmem);
> +	KUNIT_EXPECT_TRUE(test, ret);
> +
> +	drm_gem_shmem_purge(shmem);
> +	KUNIT_EXPECT_NULL(test, shmem->pages);
> +	KUNIT_EXPECT_NULL(test, shmem->sgt);
> +	KUNIT_EXPECT_EQ(test, shmem->madv, -1);
> +}
> +
> +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 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,
> +	.test_cases = drm_gem_shmem_test_cases
> +};
> +
> +kunit_test_suite(drm_gem_shmem_suite);

Looks great otherwise, thanks!
Maxime
  

On 2023-11-10 15:41, Maxime Ripard wrote:
> On Wed, Nov 08, 2023 at 02:42:03PM +0100, Marco Pagani wrote:
>> This patch introduces an initial KUnit test suite for GEM objects
>> backed by shmem buffers.
>>
>> Suggested-by: Javier Martinez Canillas <javierm@redhat.com>
>> Signed-off-by: Marco Pagani <marpagan@redhat.com>
>>
>> v2:
>> - Improved description of test cases
>> - Cleaner error handling using KUnit actions
>> - Alphabetical order in Kconfig and Makefile
>> ---
>>  drivers/gpu/drm/Kconfig                    |   9 +-
>>  drivers/gpu/drm/tests/Makefile             |   5 +-
>>  drivers/gpu/drm/tests/drm_gem_shmem_test.c | 381 +++++++++++++++++++++
>>  3 files changed, 389 insertions(+), 6 deletions(-)
>>  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..a2551c8c393a 100644
>> --- a/drivers/gpu/drm/Kconfig
>> +++ b/drivers/gpu/drm/Kconfig
>> @@ -76,14 +76,15 @@ config DRM_KUNIT_TEST
>>  	tristate "KUnit tests for DRM" if !KUNIT_ALL_TESTS
>>  	depends on DRM && KUNIT
>>  	select PRIME_NUMBERS
>> +	select DRM_BUDDY
>>  	select DRM_DISPLAY_DP_HELPER
>>  	select DRM_DISPLAY_HELPER
>> -	select DRM_LIB_RANDOM
>> -	select DRM_KMS_HELPER
>> -	select DRM_BUDDY
>> +	select DRM_EXEC
>>  	select DRM_EXPORT_FOR_TESTS if m
>> +	select DRM_GEM_SHMEM_HELPER
>> +	select DRM_KMS_HELPER
>>  	select DRM_KUNIT_TEST_HELPERS
>> -	select DRM_EXEC
>> +	select DRM_LIB_RANDOM
>>  	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..d6183b3d7688 100644
>> --- a/drivers/gpu/drm/tests/Makefile
>> +++ b/drivers/gpu/drm/tests/Makefile
>> @@ -9,15 +9,16 @@ obj-$(CONFIG_DRM_KUNIT_TEST) += \
>>  	drm_connector_test.o \
>>  	drm_damage_helper_test.o \
>>  	drm_dp_mst_helper_test.o \
>> +	drm_exec_test.o \
>>  	drm_format_helper_test.o \
>>  	drm_format_test.o \
>>  	drm_framebuffer_test.o \
>> +	drm_gem_shmem_test.o \
>>  	drm_managed_test.o \
>>  	drm_mm_test.o \
>>  	drm_modes_test.o \
>>  	drm_plane_helper_test.o \
>>  	drm_probe_helper_test.o \
>> -	drm_rect_test.o	\
>> -	drm_exec_test.o
>> +	drm_rect_test.o
> 
> Thanks for reordering the tests and symbols, but they should part of a
> preliminary patch.
> 

Okay, I'll send it as a separate patch before v3.


>>  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..983380490673
>> --- /dev/null
>> +++ b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
>> @@ -0,0 +1,381 @@
>> +// 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;
> 
> AFAICS, you're not using the dev pointer anywhere. You could remove the
> fake_dev struct entirely and pass the drm_device pointer in test->priv
>

Nice catch, thanks! It's a leftover from the previous version, where it
was used in the .exit function to free the parent dev. I'll drop it in v3.

>> +};
>> +
>> +/*
>> + * Wrappers to avoid an explicit type casting when passing action
>> + * functions to kunit_add_action().
>> + */
>> +static void kfree_wrapper(void *p)
>> +{
>> +	kfree(p);
>> +}
>> +
>> +static void sg_free_table_wrapper(void *sgt)
>> +{
>> +	sg_free_table(sgt);
>> +}
>> +
>> +static void drm_gem_shmem_free_wrapper(void *shmem)
>> +{
>> +	drm_gem_shmem_free(shmem);
>> +}
> 
> I think you need to explicitly cast the pointer (or do a temporary
> assignment to the proper type) to avoid a compiler warning.
> 

Do you mean like:

static void drm_gem_shmem_free_wrapper(void *shmem)
{
	drm_gem_shmem_free((struct drm_gem_shmem_object *)shmem);
}

I built the current version with clang 16.0.6 and gcc 13.2.1 but got
no cast warnings. Clang spotted an uninitialized variable, though.

>> +/*
>> + * Test creating a shmem GEM object backed by shmem buffer. The test
>> + * case succeeds if the GEM object is successfully allocated with the
>> + * shmem file node and object functions attributes set, and the size
>> + * attribute is equal to the correct size.
>> + */
> 
> Thanks for all those comments, it's super helpful
> 
>> +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_EXPECT_EQ(test, shmem->base.size, TEST_SIZE);
>> +	KUNIT_EXPECT_NOT_NULL(test, shmem->base.filp);
>> +	KUNIT_EXPECT_NOT_NULL(test, shmem->base.funcs);
>> +
>> +	drm_gem_shmem_free(shmem);
>> +}
>> +
>> +/*
>> + * Test creating a shmem GEM object from a scatter/gather table exported
>> + * via a DMA-BUF. The test case succeed if the GEM object is successfully
>> + * created with the shmem file node attribute equal to NULL and the sgt
>> + * attribute pointing to the scatter/gather table that has been imported.
>> + */
>> +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 = 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);
>> +
>> +	/* 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_EXPECT_EQ(test, gem_obj->size, TEST_SIZE);
>> +	KUNIT_EXPECT_NULL(test, gem_obj->filp);
>> +	KUNIT_EXPECT_NOT_NULL(test, gem_obj->funcs);
>> +
>> +	/* The scatter/gather table will be freed by drm_gem_shmem_free */
>> +	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_EXPECT_PTR_EQ(test, shmem->sgt, sgt);
>> +
>> +	drm_gem_shmem_free(shmem);
>> +}
>> +
>> +/*
>> + * Test pinning backing pages for a shmem GEM object. The test case
>> + * succeeds if a suitable number of backing pages are allocated, and
>> + * the pages table counter attribute is increased by one.
>> + */
>> +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_EXPECT_NULL(test, shmem->pages);
>> +	KUNIT_EXPECT_EQ(test, shmem->pages_use_count, 0);
>> +
>> +	ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	ret = drm_gem_shmem_pin(shmem);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +	KUNIT_ASSERT_NOT_NULL(test, shmem->pages);
>> +	KUNIT_EXPECT_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_EXPECT_NULL(test, shmem->pages);
>> +	KUNIT_EXPECT_EQ(test, shmem->pages_use_count, 0);
>> +}
>> +
>> +/*
>> + * Test creating a virtual mapping for a shmem GEM object. The test
>> + * case succeeds if the backing memory is mapped and the reference
>> + * counter for virtual mapping is increased by one. Moreover, the test
>> + * case writes and then reads a test pattern over the mapped memory.
>> + */
>> +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_EXPECT_NULL(test, shmem->vaddr);
>> +	KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 0);
>> +
>> +	ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	ret = drm_gem_shmem_vmap(shmem, &map);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +	KUNIT_ASSERT_NOT_NULL(test, shmem->vaddr);
>> +	KUNIT_ASSERT_FALSE(test, iosys_map_is_null(&map));
>> +	KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 1);
>> +
>> +	iosys_map_memset(&map, 0, TEST_BYTE, TEST_SIZE);
>> +	for (i = 0; i < TEST_SIZE; i++)
>> +		KUNIT_EXPECT_EQ(test, iosys_map_rd(&map, i, u8), TEST_BYTE);
>> +
>> +	drm_gem_shmem_vunmap(shmem, &map);
>> +	KUNIT_EXPECT_NULL(test, shmem->vaddr);
>> +	KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 0);
>> +}
>> +
>> +/*
>> + * Test exporting a scatter/gather table of pinned pages suitable for
>> + * PRIME usage from a shmem GEM object. The test case succeeds if a
>> + * scatter/gather table large enough to accommodate the backing memory
>> + * is successfully exported.
>> + */
>> +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 = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	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_EXPECT_NULL(test, shmem->sgt);
>> +
>> +	ret = kunit_add_action_or_reset(test, sg_free_table_wrapper, sgt);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	for_each_sgtable_sg(sgt, sg, si) {
>> +		KUNIT_EXPECT_NOT_NULL(test, sg);
>> +		len += sg->length;
>> +	}
>> +
>> +	KUNIT_EXPECT_GE(test, len, TEST_SIZE);
>> +}
>> +
>> +/*
>> + * Test pinning pages and exporting a scatter/gather table suitable for
>> + * driver usage from a shmem GEM object. The test case succeeds if the
>> + * backing pages are pinned and a scatter/gather table large enough to
>> + * accommodate the backing memory is successfully exported.
>> + */
>> +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, ret = 0;
>> +
>> +	shmem = drm_gem_shmem_create(&fdev->drm_dev, TEST_SIZE);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
>> +
>> +	ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	/* The scatter/gather table will be freed by drm_gem_shmem_free */
>> +	sgt = drm_gem_shmem_get_pages_sgt(shmem);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
>> +	KUNIT_ASSERT_NOT_NULL(test, shmem->pages);
>> +	KUNIT_EXPECT_EQ(test, shmem->pages_use_count, 1);
>> +	KUNIT_EXPECT_PTR_EQ(test, sgt, shmem->sgt);
>> +
>> +	for_each_sgtable_sg(sgt, sg, si) {
>> +		KUNIT_EXPECT_NOT_NULL(test, sg);
>> +		len += sg->length;
>> +	}
>> +
>> +	KUNIT_EXPECT_GE(test, len, TEST_SIZE);
>> +}
>> +
>> +/*
>> + * Test updating the madvise state of a shmem GEM object. The test
>> + * case checks that the function for setting madv updates it only if
>> + * its current value is greater or equal than zero and returns false
>> + * if it has a negative value.
>> + */
>> +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 = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	ret = drm_gem_shmem_madvise(shmem, 1);
>> +	KUNIT_EXPECT_TRUE(test, ret);
>> +	KUNIT_ASSERT_EQ(test, shmem->madv, 1);
>> +
>> +	/* Set madv to a negative value */
>> +	ret = drm_gem_shmem_madvise(shmem, -1);
>> +	KUNIT_EXPECT_FALSE(test, ret);
>> +	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
>> +
>> +	/* Check that madv cannot be set back to a positive value */
>> +	ret = drm_gem_shmem_madvise(shmem, 0);
>> +	KUNIT_EXPECT_FALSE(test, ret);
>> +	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
>> +}
>> +
>> +/*
>> + * Test purging a shmem GEM object. First, assert that a newly created
>> + * shmem GEM object is not purgeable. Then, set madvise to a positive
>> + * value and call drm_gem_shmem_get_pages_sgt() to pin and dma-map the
>> + * backing pages. Finally, assert that the shmem GEM object is now
>> + * purgeable and purge it.
>> + */
>> +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 = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	ret = drm_gem_shmem_is_purgeable(shmem);
>> +	KUNIT_EXPECT_FALSE(test, ret);
>> +
>> +	ret = drm_gem_shmem_madvise(shmem, 1);
>> +	KUNIT_EXPECT_TRUE(test, ret);
>> +
>> +	/* The scatter/gather table will be freed by drm_gem_shmem_free */
>> +	sgt = drm_gem_shmem_get_pages_sgt(shmem);
>> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
>> +
>> +	ret = drm_gem_shmem_is_purgeable(shmem);
>> +	KUNIT_EXPECT_TRUE(test, ret);
>> +
>> +	drm_gem_shmem_purge(shmem);
>> +	KUNIT_EXPECT_NULL(test, shmem->pages);
>> +	KUNIT_EXPECT_NULL(test, shmem->sgt);
>> +	KUNIT_EXPECT_EQ(test, shmem->madv, -1);
>> +}
>> +
>> +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 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,
>> +	.test_cases = drm_gem_shmem_test_cases
>> +};
>> +
>> +kunit_test_suite(drm_gem_shmem_suite);
> 
> Looks great otherwise, thanks!
> Maxime

Thanks,
Marco
  

Hi,

On Tue, Nov 14, 2023 at 05:18:08PM +0100, Marco Pagani wrote:
> On 2023-11-10 15:41, Maxime Ripard wrote:
> > On Wed, Nov 08, 2023 at 02:42:03PM +0100, Marco Pagani wrote:
> >> This patch introduces an initial KUnit test suite for GEM objects
> >> backed by shmem buffers.
> >>
> >> Suggested-by: Javier Martinez Canillas <javierm@redhat.com>
> >> Signed-off-by: Marco Pagani <marpagan@redhat.com>
> >>
> >> v2:
> >> - Improved description of test cases
> >> - Cleaner error handling using KUnit actions
> >> - Alphabetical order in Kconfig and Makefile
> >> ---
> >>  drivers/gpu/drm/Kconfig                    |   9 +-
> >>  drivers/gpu/drm/tests/Makefile             |   5 +-
> >>  drivers/gpu/drm/tests/drm_gem_shmem_test.c | 381 +++++++++++++++++++++
> >>  3 files changed, 389 insertions(+), 6 deletions(-)
> >>  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..a2551c8c393a 100644
> >> --- a/drivers/gpu/drm/Kconfig
> >> +++ b/drivers/gpu/drm/Kconfig
> >> @@ -76,14 +76,15 @@ config DRM_KUNIT_TEST
> >>  	tristate "KUnit tests for DRM" if !KUNIT_ALL_TESTS
> >>  	depends on DRM && KUNIT
> >>  	select PRIME_NUMBERS
> >> +	select DRM_BUDDY
> >>  	select DRM_DISPLAY_DP_HELPER
> >>  	select DRM_DISPLAY_HELPER
> >> -	select DRM_LIB_RANDOM
> >> -	select DRM_KMS_HELPER
> >> -	select DRM_BUDDY
> >> +	select DRM_EXEC
> >>  	select DRM_EXPORT_FOR_TESTS if m
> >> +	select DRM_GEM_SHMEM_HELPER
> >> +	select DRM_KMS_HELPER
> >>  	select DRM_KUNIT_TEST_HELPERS
> >> -	select DRM_EXEC
> >> +	select DRM_LIB_RANDOM
> >>  	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..d6183b3d7688 100644
> >> --- a/drivers/gpu/drm/tests/Makefile
> >> +++ b/drivers/gpu/drm/tests/Makefile
> >> @@ -9,15 +9,16 @@ obj-$(CONFIG_DRM_KUNIT_TEST) += \
> >>  	drm_connector_test.o \
> >>  	drm_damage_helper_test.o \
> >>  	drm_dp_mst_helper_test.o \
> >> +	drm_exec_test.o \
> >>  	drm_format_helper_test.o \
> >>  	drm_format_test.o \
> >>  	drm_framebuffer_test.o \
> >> +	drm_gem_shmem_test.o \
> >>  	drm_managed_test.o \
> >>  	drm_mm_test.o \
> >>  	drm_modes_test.o \
> >>  	drm_plane_helper_test.o \
> >>  	drm_probe_helper_test.o \
> >> -	drm_rect_test.o	\
> >> -	drm_exec_test.o
> >> +	drm_rect_test.o
> > 
> > Thanks for reordering the tests and symbols, but they should part of a
> > preliminary patch.
> > 
> 
> Okay, I'll send it as a separate patch before v3.

Thanks for taking care of this.

[...]

> >> +/*
> >> + * Wrappers to avoid an explicit type casting when passing action
> >> + * functions to kunit_add_action().
> >> + */
> >> +static void kfree_wrapper(void *p)
> >> +{
> >> +	kfree(p);
> >> +}
> >> +
> >> +static void sg_free_table_wrapper(void *sgt)
> >> +{
> >> +	sg_free_table(sgt);
> >> +}
> >> +
> >> +static void drm_gem_shmem_free_wrapper(void *shmem)
> >> +{
> >> +	drm_gem_shmem_free(shmem);
> >> +}
> > 
> > I think you need to explicitly cast the pointer (or do a temporary
> > assignment to the proper type) to avoid a compiler warning.
> > 
> 
> Do you mean like:
> 
> static void drm_gem_shmem_free_wrapper(void *shmem)
> {
> 	drm_gem_shmem_free((struct drm_gem_shmem_object *)shmem);
> }

yeah, or

static void drm_gem_shmem_free_wrapper(void *ptr)
{
	struct drm_gem_shmem_object *shmem = ptr;

	drm_gem_shmem_free(shmem);
}

> I built the current version with clang 16.0.6 and gcc 13.2.1 but got
> no cast warnings. Clang spotted an uninitialized variable, though.

The same thing happened to me, gcc didn't spot those issues but Intel's
build bot did. They might run with extra warnings.

Maxime