kunit: add debugfs /sys/kernel/debug/kunit/<suite>/results display

add debugfs support for displaying kunit test suite results; this is
especially useful for module-loaded tests to allow disentangling of
test result display from other dmesg events.  debugfs support is
provided if CONFIG_KUNIT_DEBUGFS=y.

As well as printk()ing messages, we append them to a per-test log.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 116 insertions, 31 deletions

diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 9242f932896c..a3fa21f9d918 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -10,6 +10,7 @@
 #include <linux/kernel.h>
 #include <linux/sched/debug.h>
 
+#include "debugfs.h"
 #include "string-stream.h"
 #include "try-catch-impl.h"
 
@@ -28,73 +29,116 @@ static void kunit_print_tap_version(void)
 	}
 }
 
-static size_t kunit_test_cases_len(struct kunit_case *test_cases)
+/*
+ * Append formatted message to log, size of which is limited to
+ * KUNIT_LOG_SIZE bytes (including null terminating byte).
+ */
+void kunit_log_append(char *log, const char *fmt, ...)
+{
+	char line[KUNIT_LOG_SIZE];
+	va_list args;
+	int len_left;
+
+	if (!log)
+		return;
+
+	len_left = KUNIT_LOG_SIZE - strlen(log) - 1;
+	if (len_left <= 0)
+		return;
+
+	va_start(args, fmt);
+	vsnprintf(line, sizeof(line), fmt, args);
+	va_end(args);
+
+	strncat(log, line, len_left);
+}
+EXPORT_SYMBOL_GPL(kunit_log_append);
+
+size_t kunit_suite_num_test_cases(struct kunit_suite *suite)
 {
 	struct kunit_case *test_case;
 	size_t len = 0;
 
-	for (test_case = test_cases; test_case->run_case; test_case++)
+	kunit_suite_for_each_test_case(suite, test_case)
 		len++;
 
 	return len;
 }
+EXPORT_SYMBOL_GPL(kunit_suite_num_test_cases);
 
 static void kunit_print_subtest_start(struct kunit_suite *suite)
 {
 	kunit_print_tap_version();
-	pr_info("\t# Subtest: %s\n", suite->name);
-	pr_info("\t1..%zd\n", kunit_test_cases_len(suite->test_cases));
+	kunit_log(KERN_INFO, suite, "\t# Subtest: %s", suite->name);
+	kunit_log(KERN_INFO, suite, "\t1..%zd",
+		  kunit_suite_num_test_cases(suite));
 }
 
-static void kunit_print_ok_not_ok(bool should_indent,
+static void kunit_print_ok_not_ok(void *test_or_suite,
+				  bool is_test,
 				  bool is_ok,
 				  size_t test_number,
 				  const char *description)
 {
-	const char *indent, *ok_not_ok;
-
-	if (should_indent)
-		indent = "\t";
-	else
-		indent = "";
+	struct kunit_suite *suite = is_test ? NULL : test_or_suite;
+	struct kunit *test = is_test ? test_or_suite : NULL;
 
-	if (is_ok)
-		ok_not_ok = "ok";
+	/*
+	 * We do not log the test suite results as doing so would
+	 * mean debugfs display would consist of the test suite
+	 * description and status prior to individual test results.
+	 * Hence directly printk the suite status, and we will
+	 * separately seq_printf() the suite status for the debugfs
+	 * representation.
+	 */
+	if (suite)
+		pr_info("%s %zd - %s",
+			kunit_status_to_string(is_ok),
+			test_number, description);
 	else
-		ok_not_ok = "not ok";
-
-	pr_info("%s%s %zd - %s\n", indent, ok_not_ok, test_number, description);
+		kunit_log(KERN_INFO, test, "\t%s %zd - %s",
+			  kunit_status_to_string(is_ok),
+			  test_number, description);
 }
 
-static bool kunit_suite_has_succeeded(struct kunit_suite *suite)
+bool kunit_suite_has_succeeded(struct kunit_suite *suite)
 {
 	const struct kunit_case *test_case;
 
-	for (test_case = suite->test_cases; test_case->run_case; test_case++)
+	kunit_suite_for_each_test_case(suite, test_case) {
 		if (!test_case->success)
 			return false;
+	}
 
 	return true;
 }
+EXPORT_SYMBOL_GPL(kunit_suite_has_succeeded);
 
 static void kunit_print_subtest_end(struct kunit_suite *suite)
 {
 	static size_t kunit_suite_counter = 1;
 
-	kunit_print_ok_not_ok(false,
+	kunit_print_ok_not_ok((void *)suite, false,
 			      kunit_suite_has_succeeded(suite),
 			      kunit_suite_counter++,
 			      suite->name);
 }
 
-static void kunit_print_test_case_ok_not_ok(struct kunit_case *test_case,
-					    size_t test_number)
+unsigned int kunit_test_case_num(struct kunit_suite *suite,
+				 struct kunit_case *test_case)
 {
-	kunit_print_ok_not_ok(true,
-			      test_case->success,
-			      test_number,
-			      test_case->name);
+	struct kunit_case *tc;
+	unsigned int i = 1;
+
+	kunit_suite_for_each_test_case(suite, tc) {
+		if (tc == test_case)
+			return i;
+		i++;
+	}
+
+	return 0;
 }
+EXPORT_SYMBOL_GPL(kunit_test_case_num);
 
 static void kunit_print_string_stream(struct kunit *test,
 				      struct string_stream *stream)
@@ -102,6 +146,9 @@ static void kunit_print_string_stream(struct kunit *test,
 	struct string_stream_fragment *fragment;
 	char *buf;
 
+	if (string_stream_is_empty(stream))
+		return;
+
 	buf = string_stream_get_string(stream);
 	if (!buf) {
 		kunit_err(test,
@@ -175,11 +222,14 @@ void kunit_do_assertion(struct kunit *test,
 }
 EXPORT_SYMBOL_GPL(kunit_do_assertion);
 
-void kunit_init_test(struct kunit *test, const char *name)
+void kunit_init_test(struct kunit *test, const char *name, char *log)
 {
 	spin_lock_init(&test->lock);
 	INIT_LIST_HEAD(&test->resources);
 	test->name = name;
+	test->log = log;
+	if (test->log)
+		test->log[0] = '\0';
 	test->success = true;
 }
 EXPORT_SYMBOL_GPL(kunit_init_test);
@@ -290,7 +340,7 @@ static void kunit_run_case_catch_errors(struct kunit_suite *suite,
 	struct kunit_try_catch *try_catch;
 	struct kunit test;
 
-	kunit_init_test(&test, test_case->name);
+	kunit_init_test(&test, test_case->name, test_case->log);
 	try_catch = &test.try_catch;
 
 	kunit_try_catch_init(try_catch,
@@ -303,19 +353,20 @@ static void kunit_run_case_catch_errors(struct kunit_suite *suite,
 	kunit_try_catch_run(try_catch, &context);
 
 	test_case->success = test.success;
+
+	kunit_print_ok_not_ok(&test, true, test_case->success,
+			      kunit_test_case_num(suite, test_case),
+			      test_case->name);
 }
 
 int kunit_run_tests(struct kunit_suite *suite)
 {
 	struct kunit_case *test_case;
-	size_t test_case_count = 1;
 
 	kunit_print_subtest_start(suite);
 
-	for (test_case = suite->test_cases; test_case->run_case; test_case++) {
+	kunit_suite_for_each_test_case(suite, test_case)
 		kunit_run_case_catch_errors(suite, test_case);
-		kunit_print_test_case_ok_not_ok(test_case, test_case_count++);
-	}
 
 	kunit_print_subtest_end(suite);
 
@@ -323,6 +374,37 @@ int kunit_run_tests(struct kunit_suite *suite)
 }
 EXPORT_SYMBOL_GPL(kunit_run_tests);
 
+static void kunit_init_suite(struct kunit_suite *suite)
+{
+	kunit_debugfs_create_suite(suite);
+}
+
+int __kunit_test_suites_init(struct kunit_suite **suites)
+{
+	unsigned int i;
+
+	for (i = 0; suites[i] != NULL; i++) {
+		kunit_init_suite(suites[i]);
+		kunit_run_tests(suites[i]);
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__kunit_test_suites_init);
+
+static void kunit_exit_suite(struct kunit_suite *suite)
+{
+	kunit_debugfs_destroy_suite(suite);
+}
+
+void __kunit_test_suites_exit(struct kunit_suite **suites)
+{
+	unsigned int i;
+
+	for (i = 0; suites[i] != NULL; i++)
+		kunit_exit_suite(suites[i]);
+}
+EXPORT_SYMBOL_GPL(__kunit_test_suites_exit);
+
 struct kunit_resource *kunit_alloc_and_get_resource(struct kunit *test,
 						    kunit_resource_init_t init,
 						    kunit_resource_free_t free,
@@ -489,12 +571,15 @@ EXPORT_SYMBOL_GPL(kunit_cleanup);
 
 static int __init kunit_init(void)
 {
+	kunit_debugfs_init();
+
 	return 0;
 }
 late_initcall(kunit_init);
 
 static void __exit kunit_exit(void)
 {
+	kunit_debugfs_cleanup();
 }
 module_exit(kunit_exit);