kunit: Pass parameterized test context to generate_params()

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.

Link: https://lore.kernel.org/r/20250826091341.1427123-4-davidgow@google.com
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>
[Catch some additional gen_params signatures in drm/xe/tests --David]
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Author: Marie Zhussupova

drivers/gpu/drm/xe/tests/xe_pci.c

@@ -44,9 +44,9 @@ KUNIT_ARRAY_PARAM(pci_id, pciidlist, xe_pci_id_kunit_desc);
  *
  * Return: pointer to the next parameter or NULL if no more parameters
  */
-const void *xe_pci_graphics_ip_gen_param(const void *prev, char *desc)
+const void *xe_pci_graphics_ip_gen_param(struct kunit *test, const void *prev, char *desc)
 {
-	return graphics_ip_gen_params(prev, desc);
+	return graphics_ip_gen_params(test, prev, desc);
 }
 EXPORT_SYMBOL_IF_KUNIT(xe_pci_graphics_ip_gen_param);
 
@@ -61,9 +61,9 @@ EXPORT_SYMBOL_IF_KUNIT(xe_pci_graphics_ip_gen_param);
  *
  * Return: pointer to the next parameter or NULL if no more parameters
  */
-const void *xe_pci_media_ip_gen_param(const void *prev, char *desc)
+const void *xe_pci_media_ip_gen_param(struct kunit *test, const void *prev, char *desc)
 {
-	return media_ip_gen_params(prev, desc);
+	return media_ip_gen_params(test, prev, desc);
 }
 EXPORT_SYMBOL_IF_KUNIT(xe_pci_media_ip_gen_param);
 
@@ -78,9 +78,9 @@ EXPORT_SYMBOL_IF_KUNIT(xe_pci_media_ip_gen_param);
  *
  * Return: pointer to the next parameter or NULL if no more parameters
  */
-const void *xe_pci_id_gen_param(const void *prev, char *desc)
+const void *xe_pci_id_gen_param(struct kunit *test, const void *prev, char *desc)
 {
-	const struct pci_device_id *pci = pci_id_gen_params(prev, desc);
+	const struct pci_device_id *pci = pci_id_gen_params(test, prev, desc);
 
 	return pci->driver_data ? pci : NULL;
 }
@@ -159,7 +159,7 @@ 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;

drivers/gpu/drm/xe/tests/xe_pci_test.h

@@ -7,6 +7,7 @@
 #define _XE_PCI_TEST_H_
 
 #include <linux/types.h>
+#include <kunit/test.h>
 
 #include "xe_platform_types.h"
 #include "xe_sriov_types.h"
@@ -25,9 +26,9 @@ struct xe_pci_fake_data {
 
 int xe_pci_fake_device_init(struct xe_device *xe);
 
-const void *xe_pci_graphics_ip_gen_param(const void *prev, char *desc);
-const void *xe_pci_media_ip_gen_param(const void *prev, char *desc);
-const void *xe_pci_id_gen_param(const void *prev, char *desc);
-const void *xe_pci_live_device_gen_param(const void *prev, char *desc);
+const void *xe_pci_graphics_ip_gen_param(struct kunit *test, const void *prev, char *desc);
+const void *xe_pci_media_ip_gen_param(struct kunit *test, const void *prev, char *desc);
+const void *xe_pci_id_gen_param(struct kunit *test, const void *prev, char *desc);
+const void *xe_pci_live_device_gen_param(struct kunit *test, const void *prev, char *desc);
 
 #endif

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);
@@ -1703,7 +1704,8 @@ 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))) {					\
@@ -1724,7 +1726,8 @@ 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))) {					\

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;
 

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