[PATCH 1/9] kunit: Add parent kunit for parameterized test context

[Marie Zhussupova <marievic@google.com>]

Currently, KUnit parameterized tests lack a mechanism
to share resources across individual test invocations
because the same `struct kunit` instance is reused for
each test.

This patch refactors kunit_run_tests() to provide each
parameterized test with its own `struct kunit` instance.
A new parent pointer is added to `struct kunit`, allowing
individual parameterized tests to reference a shared
parent kunit instance. Resources added to this parent
will then be accessible to all individual parameter
test executions.

Signed-off-by: Marie Zhussupova <marievic@google.com>
---
 include/kunit/test.h | 12 ++++++++++--
 lib/kunit/test.c     | 32 +++++++++++++++++++-------------
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 39c768f87dc9..a42d0c8cb985 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -268,14 +268,22 @@ struct kunit_suite_set {
  *
  * @priv: for user to store arbitrary data. Commonly used to pass data
  *	  created in the init function (see &struct kunit_suite).
+ * @parent: for user to store data that they want to shared across
+ *	    parameterized tests.
  *
  * Used to store information about the current context under which the test
  * is running. Most of this data is private and should only be accessed
- * indirectly via public functions; the one exception is @priv which can be
- * used by the test writer to store arbitrary data.
+ * indirectly via public functions; the two exceptions are @priv and @parent
+ * which can be used by the test writer to store arbitrary data or data that is
+ * available to all parameter test executions, respectively.
  */
 struct kunit {
 	void *priv;
+	/*
+	 * Reference to the parent struct kunit for storing shared resources
+	 * during parameterized testing.
+	 */
+	struct kunit *parent;
 
 	/* private: internal use only. */
 	const char *name; /* Read only after initialization! */
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index f3c6b11f12b8..4d6a39eb2c80 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -647,6 +647,7 @@ int kunit_run_tests(struct kunit_suite *suite)
 	struct kunit_case *test_case;
 	struct kunit_result_stats suite_stats = { 0 };
 	struct kunit_result_stats total_stats = { 0 };
+	const void *curr_param;
 
 	/* Taint the kernel so we know we've run tests. */
 	add_taint(TAINT_TEST, LOCKDEP_STILL_OK);
@@ -679,36 +680,39 @@ int kunit_run_tests(struct kunit_suite *suite)
 		} else {
 			/* Get initial param. */
 			param_desc[0] = '\0';
-			test.param_value = test_case->generate_params(NULL, param_desc);
+			/* TODO: Make generate_params try-catch */
+			curr_param = test_case->generate_params(NULL, param_desc);
 			test_case->status = KUNIT_SKIPPED;
 			kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT KUNIT_SUBTEST_INDENT
 				  "KTAP version 1\n");
 			kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT KUNIT_SUBTEST_INDENT
 				  "# Subtest: %s", test_case->name);
 
-			while (test.param_value) {
-				kunit_run_case_catch_errors(suite, test_case, &test);
+			while (curr_param) {
+				struct kunit param_test = {
+					.param_value = curr_param,
+					.param_index = ++test.param_index,
+					.parent = &test,
+				};
+				kunit_init_test(&param_test, test_case->name, test_case->log);
+				kunit_run_case_catch_errors(suite, test_case, &param_test);
 
 				if (param_desc[0] == '\0') {
 					snprintf(param_desc, sizeof(param_desc),
 						 "param-%d", test.param_index);
 				}
 
-				kunit_print_ok_not_ok(&test, KUNIT_LEVEL_CASE_PARAM,
-						      test.status,
-						      test.param_index + 1,
+				kunit_print_ok_not_ok(&param_test, KUNIT_LEVEL_CASE_PARAM,
+						      param_test.status,
+						      param_test.param_index,
 						      param_desc,
-						      test.status_comment);
+						      param_test.status_comment);
 
-				kunit_update_stats(&param_stats, test.status);
+				kunit_update_stats(&param_stats, param_test.status);
 
 				/* Get next param. */
 				param_desc[0] = '\0';
-				test.param_value = test_case->generate_params(test.param_value, param_desc);
-				test.param_index++;
-				test.status = KUNIT_SUCCESS;
-				test.status_comment[0] = '\0';
-				test.priv = NULL;
+				curr_param = test_case->generate_params(curr_param, param_desc);
 			}
 		}
 
@@ -723,6 +727,8 @@ int kunit_run_tests(struct kunit_suite *suite)
 
 		kunit_update_stats(&suite_stats, test_case->status);
 		kunit_accumulate_stats(&total_stats, param_stats);
+		/* TODO: Put this kunit_cleanup into a try-catch. */
+		kunit_cleanup(&test);
 	}
 
 	if (suite->suite_exit)
-- 
2.50.1.552.g942d659e1b-goog