kunit: Introduce param_init/exit for parameterized test context management

Add (*param_init) and (*param_exit) function pointers to
`struct kunit_case`. Users will be able to set them via the new
KUNIT_CASE_PARAM_WITH_INIT() macro.

param_init/exit will be invoked by kunit_run_tests() once before and once
after the parameterized test, respectively. They will receive the
`struct kunit` that holds the parameterized test context; facilitating
init and exit for shared state.

This patch also sets param_init/exit to None in rust/kernel/kunit.rs.

Link: https://lore.kernel.org/r/20250826091341.1427123-3-davidgow@google.com
Reviewed-by: Rae Moar <rmoar@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Marie Zhussupova <marievic@google.com>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 26 insertions, 1 deletions

diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 587b5c51db58..0fe61dec5a96 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -641,6 +641,20 @@ static void kunit_accumulate_stats(struct kunit_result_stats *total,
 	total->total += add.total;
 }
 
+static void kunit_init_parent_param_test(struct kunit_case *test_case, struct kunit *test)
+{
+	if (test_case->param_init) {
+		int err = test_case->param_init(test);
+
+		if (err) {
+			kunit_err(test_case, KUNIT_SUBTEST_INDENT KUNIT_SUBTEST_INDENT
+				"# failed to initialize parent parameter test (%d)", err);
+			test->status = KUNIT_FAILURE;
+			test_case->status = KUNIT_FAILURE;
+		}
+	}
+}
+
 int kunit_run_tests(struct kunit_suite *suite)
 {
 	char param_desc[KUNIT_PARAM_DESC_SIZE];
@@ -678,6 +692,11 @@ int kunit_run_tests(struct kunit_suite *suite)
 			kunit_run_case_catch_errors(suite, test_case, &test);
 			kunit_update_stats(&param_stats, test.status);
 		} else {
+			kunit_init_parent_param_test(test_case, &test);
+			if (test_case->status == KUNIT_FAILURE) {
+				kunit_update_stats(&param_stats, test.status);
+				goto test_case_end;
+			}
 			/* Get initial param. */
 			param_desc[0] = '\0';
 			/* TODO: Make generate_params try-catch */
@@ -714,10 +733,16 @@ int kunit_run_tests(struct kunit_suite *suite)
 				param_desc[0] = '\0';
 				curr_param = test_case->generate_params(curr_param, param_desc);
 			}
+			/*
+			 * TODO: Put into a try catch. Since we don't need suite->exit
+			 * for it we can't reuse kunit_try_run_cleanup for this yet.
+			 */
+			if (test_case->param_exit)
+				test_case->param_exit(&test);
 			/* TODO: Put this kunit_cleanup into a try-catch. */
 			kunit_cleanup(&test);
 		}
-
+test_case_end:
 		kunit_print_attr((void *)test_case, true, KUNIT_LEVEL_CASE);
 
 		kunit_print_test_stats(&test, param_stats);