[PATCH v3 3/3] kunit: Allow kunit test modules to use test filtering

[Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>]

External tools, e.g., Intel GPU tools (IGT), support execution of
individual selftests provided by kernel modules.  That could be also
applicable to kunit test modules if they provided test filtering.  But
test filtering is now possible only when kunit code is built into the
kernel.  Moreover, a filter can be specified only at boot time, then
reboot is required each time a different filter is needed.

Build the test filtering code also when kunit is configured as a module,
expose test filtering functions to other kunit source files, and use them
in kunit module notifier callback functions.  Userspace can then reload
the kunit module with a value of the filter_glob parameter tuned to a
specific kunit test module every time it wants to limit the scope of tests
executed on that module load.  Make the kunit.filter_glob parameter
visible in sysfs for user convenience.

v3: Fix CONFIG_GLOB, required by filtering fuctions, not selected when
    building as a module.
v2: Fix new name of a structure moved to kunit namespace not updated
    across all uses.

Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
---
 include/kunit/test.h | 13 +++++++++++++
 lib/kunit/Kconfig    |  2 +-
 lib/kunit/executor.c | 42 ++++++++++++++++++++++--------------------
 lib/kunit/test.c     | 22 ++++++++++++++++++++++
 4 files changed, 58 insertions(+), 21 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 6d693f21a4833..14ff12e72252a 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -190,6 +190,12 @@ struct kunit_suite {
 	int suite_init_err;
 };
 
+/* Stores an array of suites, end points one past the end */
+struct kunit_suite_set {
+	struct kunit_suite * const *start;
+	struct kunit_suite * const *end;
+};
+
 /**
  * struct kunit - represents a running instance of a test.
  *
@@ -238,6 +244,7 @@ static inline void kunit_set_failure(struct kunit *test)
 
 bool kunit_enabled(void);
 const char *kunit_action(void);
+const char *kunit_filter_glob(void);
 
 void kunit_init_test(struct kunit *test, const char *name, char *log);
 
@@ -248,6 +255,12 @@ size_t kunit_suite_num_test_cases(struct kunit_suite *suite);
 unsigned int kunit_test_case_num(struct kunit_suite *suite,
 				 struct kunit_case *test_case);
 
+struct kunit_suite_set
+kunit_filter_suites(const struct kunit_suite_set *suite_set,
+		    const char *filter_glob,
+		    int *err);
+void kunit_free_suite_set(struct kunit_suite_set suite_set);
+
 int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_suites);
 
 void __kunit_test_suites_exit(struct kunit_suite **suites, int num_suites);
diff --git a/lib/kunit/Kconfig b/lib/kunit/Kconfig
index 626719b95badd..68a6daec0aef1 100644
--- a/lib/kunit/Kconfig
+++ b/lib/kunit/Kconfig
@@ -4,7 +4,7 @@
 
 menuconfig KUNIT
 	tristate "KUnit - Enable support for unit tests"
-	select GLOB if KUNIT=y
+	select GLOB
 	help
 	  Enables support for kernel unit tests (KUnit), a lightweight unit
 	  testing and mocking framework for the Linux kernel. These tests are
diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c
index d1c0616569dfd..49fe40cc8f1af 100644
--- a/lib/kunit/executor.c
+++ b/lib/kunit/executor.c
@@ -25,14 +25,17 @@ const char *kunit_action(void)
 	return action_param;
 }
 
-#if IS_BUILTIN(CONFIG_KUNIT)
-
 static char *filter_glob_param;
 
-module_param_named(filter_glob, filter_glob_param, charp, 0);
+module_param_named(filter_glob, filter_glob_param, charp, 0400);
 MODULE_PARM_DESC(filter_glob,
 		"Filter which KUnit test suites/tests run at boot-time, e.g. list* or list*.*del_test");
 
+const char *kunit_filter_glob(void)
+{
+	return filter_glob_param;
+}
+
 /* glob_match() needs NULL terminated strings, so we need a copy of filter_glob_param. */
 struct kunit_test_filter {
 	char *suite_glob;
@@ -96,16 +99,7 @@ kunit_filter_tests(const struct kunit_suite *const suite, const char *test_glob)
 	return copy;
 }
 
-static char *kunit_shutdown;
-core_param(kunit_shutdown, kunit_shutdown, charp, 0644);
-
-/* Stores an array of suites, end points one past the end */
-struct suite_set {
-	struct kunit_suite * const *start;
-	struct kunit_suite * const *end;
-};
-
-static void kunit_free_suite_set(struct suite_set suite_set)
+void kunit_free_suite_set(struct kunit_suite_set suite_set)
 {
 	struct kunit_suite * const *suites;
 
@@ -114,13 +108,14 @@ static void kunit_free_suite_set(struct suite_set suite_set)
 	kfree(suite_set.start);
 }
 
-static struct suite_set kunit_filter_suites(const struct suite_set *suite_set,
-					    const char *filter_glob,
-					    int *err)
+struct kunit_suite_set
+kunit_filter_suites(const struct kunit_suite_set *suite_set,
+		    const char *filter_glob,
+		    int *err)
 {
 	int i;
 	struct kunit_suite **copy, *filtered_suite;
-	struct suite_set filtered;
+	struct kunit_suite_set filtered;
 	struct kunit_test_filter filter;
 
 	const size_t max = suite_set->end - suite_set->start;
@@ -155,6 +150,11 @@ static struct suite_set kunit_filter_suites(const struct suite_set *suite_set,
 	return filtered;
 }
 
+#if IS_BUILTIN(CONFIG_KUNIT)
+
+static char *kunit_shutdown;
+core_param(kunit_shutdown, kunit_shutdown, charp, 0644);
+
 static void kunit_handle_shutdown(void)
 {
 	if (!kunit_shutdown)
@@ -169,7 +169,7 @@ static void kunit_handle_shutdown(void)
 
 }
 
-static void kunit_exec_run_tests(struct suite_set *suite_set)
+static void kunit_exec_run_tests(struct kunit_suite_set *suite_set)
 {
 	size_t num_suites = suite_set->end - suite_set->start;
 
@@ -179,7 +179,7 @@ static void kunit_exec_run_tests(struct suite_set *suite_set)
 	__kunit_test_suites_init(suite_set->start, num_suites);
 }
 
-static void kunit_exec_list_tests(struct suite_set *suite_set)
+static void kunit_exec_list_tests(struct kunit_suite_set *suite_set)
 {
 	struct kunit_suite * const *suites;
 	struct kunit_case *test_case;
@@ -195,7 +195,9 @@ static void kunit_exec_list_tests(struct suite_set *suite_set)
 
 int kunit_run_all_tests(void)
 {
-	struct suite_set suite_set = {__kunit_suites_start, __kunit_suites_end};
+	struct kunit_suite_set suite_set = {
+		__kunit_suites_start, __kunit_suites_end,
+	};
 	int err = 0;
 	if (!kunit_enabled()) {
 		pr_info("kunit: disabled\n");
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 413d9fd364a8d..bfc2f65bd1dae 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -757,6 +757,22 @@ EXPORT_SYMBOL_GPL(__kunit_test_suites_exit);
 #ifdef CONFIG_MODULES
 static void kunit_module_init(struct module *mod)
 {
+	struct kunit_suite_set suite_set = {
+		mod->kunit_suites, mod->kunit_suites + mod->num_kunit_suites,
+	};
+	int err = 0;
+
+	suite_set = kunit_filter_suites(&suite_set,
+					kunit_filter_glob() ?: "*.*", &err);
+	if (err) {
+		pr_err("kunit module: error filtering suites: %d\n",
+		       err);
+		kfree(suite_set.start);
+		suite_set.start = NULL;
+	}
+	mod->kunit_suites = (struct kunit_suite **)suite_set.start;
+	mod->num_kunit_suites = suite_set.end - suite_set.start;
+
 	if (mod->num_kunit_suites > 0) {
 		pr_info("KTAP version 1\n");
 		pr_info("1..%d\n", mod->num_kunit_suites);
@@ -767,7 +783,13 @@ static void kunit_module_init(struct module *mod)
 
 static void kunit_module_exit(struct module *mod)
 {
+	struct kunit_suite_set suite_set = {
+		mod->kunit_suites, mod->kunit_suites + mod->num_kunit_suites,
+	};
+
 	__kunit_test_suites_exit(mod->kunit_suites, mod->num_kunit_suites);
+	if (suite_set.start)
+		kunit_free_suite_set(suite_set);
 }
 
 static int kunit_module_notify(struct notifier_block *nb, unsigned long val,
-- 
2.41.0