[PATCH v3 3/7] kunit: Pass parameterized test context to generate_params()

[Marie Zhussupova <marievic@google.com>]

To enable more complex parameterized testing scenarios, the
generate_params() function needs additional context beyond just
the previously generated parameter. This patch modifies the
generate_params() function signature to include an extra
`struct kunit *test` argument, giving test users access to the
parameterized test context when generating parameters.

The `struct kunit *test` argument was added as the first parameter
to the function signature as it aligns with the convention of other
KUnit functions that accept `struct kunit *test` first. This also
mirrors the "this" or "self" reference found in object-oriented
programming languages.

This patch also modifies xe_pci_live_device_gen_param() in xe_pci.c
and nthreads_gen_params() in kcsan_test.c to reflect this signature
change.

Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Rae Moar <rmoar@google.com>
Acked-by: Marco Elver <elver@google.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Marie Zhussupova <marievic@google.com>
---

Changes in v3:
v2: https://lore.kernel.org/all/20250811221739.2694336-4-marievic@google.com/
- Commit message formatting.

Changes in v2:
v1: https://lore.kernel.org/all/20250729193647.3410634-4-marievic@google.com/
    https://lore.kernel.org/all/20250729193647.3410634-5-marievic@google.com/
    https://lore.kernel.org/all/20250729193647.3410634-6-marievic@google.com/
- generate_params signature changes in xe_pci.c and kcsan_test.c were
  squashed into a single patch to avoid in-between breakages in the series.
- The comments and the commit message were changed to reflect the
  parameterized testing terminology. See the patch series cover letter
  change log for the definitions.

---
 drivers/gpu/drm/xe/tests/xe_pci.c | 2 +-
 include/kunit/test.h              | 9 ++++++---
 kernel/kcsan/kcsan_test.c         | 2 +-
 lib/kunit/test.c                  | 5 +++--
 4 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/xe/tests/xe_pci.c b/drivers/gpu/drm/xe/tests/xe_pci.c
index 1d3e2e50c355..62c016e84227 100644
--- a/drivers/gpu/drm/xe/tests/xe_pci.c
+++ b/drivers/gpu/drm/xe/tests/xe_pci.c
@@ -129,7 +129,7 @@ EXPORT_SYMBOL_IF_KUNIT(xe_pci_fake_device_init);
  * Return: pointer to the next &struct xe_device ready to be used as a parameter
  *         or NULL if there are no more Xe devices on the system.
  */
-const void *xe_pci_live_device_gen_param(const void *prev, char *desc)
+const void *xe_pci_live_device_gen_param(struct kunit *test, const void *prev, char *desc)
 {
 	const struct xe_device *xe = prev;
 	struct device *dev = xe ? xe->drm.dev : NULL;
diff --git a/include/kunit/test.h b/include/kunit/test.h
index d2e1b986b161..b527189d2d1c 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -128,7 +128,8 @@ struct kunit_attributes {
 struct kunit_case {
 	void (*run_case)(struct kunit *test);
 	const char *name;
-	const void* (*generate_params)(const void *prev, char *desc);
+	const void* (*generate_params)(struct kunit *test,
+				       const void *prev, char *desc);
 	struct kunit_attributes attr;
 	int (*param_init)(struct kunit *test);
 	void (*param_exit)(struct kunit *test);
@@ -1691,7 +1692,8 @@ do {									       \
  * Define function @name_gen_params which uses @array to generate parameters.
  */
 #define KUNIT_ARRAY_PARAM(name, array, get_desc)						\
-	static const void *name##_gen_params(const void *prev, char *desc)			\
+	static const void *name##_gen_params(struct kunit *test,				\
+					     const void *prev, char *desc)			\
 	{											\
 		typeof((array)[0]) *__next = prev ? ((typeof(__next)) prev) + 1 : (array);	\
 		if (__next - (array) < ARRAY_SIZE((array))) {					\
@@ -1712,7 +1714,8 @@ do {									       \
  * Define function @name_gen_params which uses @array to generate parameters.
  */
 #define KUNIT_ARRAY_PARAM_DESC(name, array, desc_member)					\
-	static const void *name##_gen_params(const void *prev, char *desc)			\
+	static const void *name##_gen_params(struct kunit *test,				\
+					     const void *prev, char *desc)			\
 	{											\
 		typeof((array)[0]) *__next = prev ? ((typeof(__next)) prev) + 1 : (array);	\
 		if (__next - (array) < ARRAY_SIZE((array))) {					\
diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c
index c2871180edcc..fc76648525ac 100644
--- a/kernel/kcsan/kcsan_test.c
+++ b/kernel/kcsan/kcsan_test.c
@@ -1383,7 +1383,7 @@ static void test_atomic_builtins_missing_barrier(struct kunit *test)
  * The thread counts are chosen to cover potentially interesting boundaries and
  * corner cases (2 to 5), and then stress the system with larger counts.
  */
-static const void *nthreads_gen_params(const void *prev, char *desc)
+static const void *nthreads_gen_params(struct kunit *test, const void *prev, char *desc)
 {
 	long nthreads = (long)prev;
 
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 917df2e1688d..ac8fa8941a6a 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -700,7 +700,7 @@ int kunit_run_tests(struct kunit_suite *suite)
 			/* Get initial param. */
 			param_desc[0] = '\0';
 			/* TODO: Make generate_params try-catch */
-			curr_param = test_case->generate_params(NULL, param_desc);
+			curr_param = test_case->generate_params(&test, NULL, param_desc);
 			test_case->status = KUNIT_SKIPPED;
 			kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT KUNIT_SUBTEST_INDENT
 				  "KTAP version 1\n");
@@ -731,7 +731,8 @@ int kunit_run_tests(struct kunit_suite *suite)
 
 				/* Get next param. */
 				param_desc[0] = '\0';
-				curr_param = test_case->generate_params(curr_param, param_desc);
+				curr_param = test_case->generate_params(&test, curr_param,
+									param_desc);
 			}
 			/*
 			 * TODO: Put into a try catch. Since we don't need suite->exit
-- 
2.51.0.rc1.167.g924127e9c0-goog