============================================================
======== [PASSED] kunit_executor_test ========
[PASSED] parse_filter_test
============================================================
Testing complete. 1 tests run. 0 failed. 0 crashed.

$ ./tools/testing/kunit/kunit.py run --kunitconfig=lib/kunit '*.no_matching_tests'
...
[ERROR] no tests run!

Signed-off-by: Daniel Latypov <dlatypov@google.com>
---
v1 -> v2: update Documentation/.../running_tips.rst
---
 .../dev-tools/kunit/running_tips.rst          |  11 +-
 lib/kunit/executor.c                          | 107 +++++++++++++++--
 lib/kunit/executor_test.c                     | 109 +++++++++++++++---
 3 files changed, 201 insertions(+), 26 deletions(-)

diff --git a/Documentation/dev-tools/kunit/running_tips.rst b/Documentation/dev-tools/kunit/running_tips.rst
index d1626d548fa5..f471bcbdabd4 100644
--- a/Documentation/dev-tools/kunit/running_tips.rst
+++ b/Documentation/dev-tools/kunit/running_tips.rst
@@ -25,8 +25,8 @@ It can be handy to create a bash function like:
 Running a subset of tests
 -------------------------
 
-``kunit.py run`` accepts an optional glob argument to filter tests. Currently
-this only matches against suite names, but this may change in the future.
+``kunit.py run`` accepts an optional glob argument to filter tests. The format
+is ``"<suite_glob>[.test_glob]"``.
 
 Say that we wanted to run the sysctl tests, we could do so via:
 
@@ -35,6 +35,13 @@ Say that we wanted to run the sysctl tests, we could do so via:
 	$ echo -e 'CONFIG_KUNIT=y\nCONFIG_KUNIT_ALL_TESTS=y' > .kunit/.kunitconfig
 	$ ./tools/testing/kunit/kunit.py run 'sysctl*'
 
+We can filter down to just the "write" tests via:
+
+.. code-block:: bash
+
+	$ echo -e 'CONFIG_KUNIT=y\nCONFIG_KUNIT_ALL_TESTS=y' > .kunit/.kunitconfig
+	$ ./tools/testing/kunit/kunit.py run 'sysctl*.*write*'
+
 We're paying the cost of building more tests than we need this way, but it's
 easier than fiddling with ``.kunitconfig`` files or commenting out
 ``kunit_suite``'s.
diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c
index acd1de436f59..bab3ab940acc 100644
--- a/lib/kunit/executor.c
+++ b/lib/kunit/executor.c
@@ -17,21 +17,80 @@ extern struct kunit_suite * const * const __kunit_suites_end[];
 static char *filter_glob_param;
 module_param_named(filter_glob, filter_glob_param, charp, 0);
 MODULE_PARM_DESC(filter_glob,
-		"Filter which KUnit test suites run at boot-time, e.g. list*");
+		"Filter which KUnit test suites/tests run at boot-time, e.g. list* or list*.*del_test");
+
+/* glob_match() needs NULL terminated strings, so we need a copy of filter_glob_param. */
+struct kunit_test_filter {
+	char *suite_glob;
+	char *test_glob;
+};
+
+/* Split "suite_glob.test_glob" into two. Assumes filter_glob is not empty. */
+static void kunit_parse_filter_glob(struct kunit_test_filter *parsed,
+				    const char *filter_glob)
+{
+	const int len = strlen(filter_glob);
+	const char *period = strchr(filter_glob, '.');
+
+	if (!period) {
+		parsed->suite_glob = kmalloc(len, GFP_KERNEL);
+		parsed->test_glob = NULL;
+		strcpy(parsed->suite_glob, filter_glob);
+		return;
+	}
+
+	parsed->suite_glob = kzalloc(period - filter_glob + 1, GFP_KERNEL);
+	parsed->test_glob = kzalloc(len - (period - filter_glob) + 1, GFP_KERNEL);
+
+	strncpy(parsed->suite_glob, filter_glob, period - filter_glob);
+	strncpy(parsed->test_glob, period + 1, len - (period - filter_glob));
+}
+
+/* Create a copy of suite with only tests that match test_glob. */
+static struct kunit_suite *
+kunit_filter_tests(struct kunit_suite *const suite, const char *test_glob)
+{
+	int n = 0;
+	struct kunit_case *filtered, *test_case;
+	struct kunit_suite *copy;
+
+	kunit_suite_for_each_test_case(suite, test_case) {
+		if (!test_glob || glob_match(test_glob, test_case->name))
+			++n;
+	}
+
+	if (n == 0)
+		return NULL;
+
+	/* Use memcpy to workaround copy->name being const. */
+	copy = kmalloc(sizeof(*copy), GFP_KERNEL);
+	memcpy(copy, suite, sizeof(*copy));
+
+	filtered = kcalloc(n + 1, sizeof(*filtered), GFP_KERNEL);
+
+	n = 0;
+	kunit_suite_for_each_test_case(suite, test_case) {
+		if (!test_glob || glob_match(test_glob, test_case->name))
+			filtered[n++] = *test_case;
+	}
+
+	copy->test_cases = filtered;
+	return copy;
+}
 
 static char *kunit_shutdown;
 core_param(kunit_shutdown, kunit_shutdown, charp, 0644);
 
 static struct kunit_suite * const *
 kunit_filter_subsuite(struct kunit_suite * const * const subsuite,
-			const char *filter_glob)
+		      struct kunit_test_filter *filter)
 {
 	int i, n = 0;
-	struct kunit_suite **filtered;
+	struct kunit_suite **filtered, *filtered_suite;
 
 	n = 0;
-	for (i = 0; subsuite[i] != NULL; ++i) {
-		if (glob_match(filter_glob, subsuite[i]->name))
+	for (i = 0; subsuite[i]; ++i) {
+		if (glob_match(filter->suite_glob, subsuite[i]->name))
 			++n;
 	}
 
@@ -44,8 +103,11 @@ kunit_filter_subsuite(struct kunit_suite * const * const subsuite,
 
 	n = 0;
 	for (i = 0; subsuite[i] != NULL; ++i) {
-		if (glob_match(filter_glob, subsuite[i]->name))
-			filtered[n++] = subsuite[i];
+		if (!glob_match(filter->suite_glob, subsuite[i]->name))
+			continue;
+		filtered_suite = kunit_filter_tests(subsuite[i], filter->test_glob);
+		if (filtered_suite)
+			filtered[n++] = filtered_suite;
 	}
 	filtered[n] = NULL;
 
@@ -57,12 +119,32 @@ struct suite_set {
 	struct kunit_suite * const * const *end;
 };
 
+static void kunit_free_subsuite(struct kunit_suite * const *subsuite)
+{
+	unsigned int i;
+
+	for (i = 0; subsuite[i]; i++)
+		kfree(subsuite[i]);
+
+	kfree(subsuite);
+}
+
+static void kunit_free_suite_set(struct suite_set suite_set)
+{
+	struct kunit_suite * const * const *suites;
+
+	for (suites = suite_set.start; suites < suite_set.end; suites++)
+		kunit_free_subsuite(*suites);
+	kfree(suite_set.start);
+}
+
 static struct suite_set kunit_filter_suites(const struct suite_set *suite_set,
 					    const char *filter_glob)
 {
 	int i;
 	struct kunit_suite * const **copy, * const *filtered_subsuite;
 	struct suite_set filtered;
+	struct kunit_test_filter filter;
 
 	const size_t max = suite_set->end - suite_set->start;
 
@@ -73,12 +155,17 @@ static struct suite_set kunit_filter_suites(const struct suite_set *suite_set,
 		return filtered;
 	}
 
+	kunit_parse_filter_glob(&filter, filter_glob);
+
 	for (i = 0; i < max; ++i) {
-		filtered_subsuite = kunit_filter_subsuite(suite_set->start[i], filter_glob);
+		filtered_subsuite = kunit_filter_subsuite(suite_set->start[i], &filter);
 		if (filtered_subsuite)
 			*copy++ = filtered_subsuite;
 	}
 	filtered.end = copy;
+
+	kfree(filter.suite_glob);
+	kfree(filter.test_glob);
 	return filtered;
 }
 
@@ -126,9 +213,7 @@ int kunit_run_all_tests(void)
 		__kunit_test_suites_init(*suites);
 
 	if (filter_glob_param) { /* a copy was made of each array */
-		for (suites = suite_set.start; suites < suite_set.end; suites++)
-			kfree(*suites);
-		kfree(suite_set.start);
+		kunit_free_suite_set(suite_set);
 	}
 
 	kunit_handle_shutdown();
diff --git a/lib/kunit/executor_test.c b/lib/kunit/executor_test.c
index cdbe54b16501..dbb49c099e02 100644
--- a/lib/kunit/executor_test.c
+++ b/lib/kunit/executor_test.c
@@ -9,38 +9,103 @@
 #include <kunit/test.h>
 
 static void kfree_at_end(struct kunit *test, const void *to_free);
+static void free_subsuite_at_end(struct kunit *test,
+				 struct kunit_suite *const *to_free);
 static struct kunit_suite *alloc_fake_suite(struct kunit *test,
-					    const char *suite_name);
+					    const char *suite_name,
+					    struct kunit_case *test_cases);
+
+void dummy_test(struct kunit *test) {}
+
+struct kunit_case dummy_test_cases[] = {
+	/* .run_case is not important, just needs to be non-NULL */
+	{ .name = "test1", .run_case = dummy_test },
+	{ .name = "test2", .run_case = dummy_test },
+	{},
+};
+
+static void parse_filter_test(struct kunit *test)
+{
+	struct kunit_test_filter filter = {NULL, NULL};
+
+	kunit_parse_filter_glob(&filter, "suite");
+	KUNIT_EXPECT_STREQ(test, filter.suite_glob, "suite");
+	KUNIT_EXPECT_FALSE(test, filter.test_glob);
+	kfree(filter.suite_glob);
+	kfree(filter.test_glob);
+
+	kunit_parse_filter_glob(&filter, "suite.test");
+	KUNIT_EXPECT_STREQ(test, filter.suite_glob, "suite");
+	KUNIT_EXPECT_STREQ(test, filter.test_glob, "test");
+	kfree(filter.suite_glob);
+	kfree(filter.test_glob);
+}
 
 static void filter_subsuite_test(struct kunit *test)
 {
 	struct kunit_suite *subsuite[3] = {NULL, NULL, NULL};
 	struct kunit_suite * const *filtered;
+	struct kunit_test_filter filter = {
+		.suite_glob = "suite2",
+		.test_glob = NULL,
+	};
 
-	subsuite[0] = alloc_fake_suite(test, "suite1");
-	subsuite[1] = alloc_fake_suite(test, "suite2");
+	subsuite[0] = alloc_fake_suite(test, "suite1", dummy_test_cases);
+	subsuite[1] = alloc_fake_suite(test, "suite2", dummy_test_cases);
 
 	/* Want: suite1, suite2, NULL -> suite2, NULL */
-	filtered = kunit_filter_subsuite(subsuite, "suite2*");
+	filtered = kunit_filter_subsuite(subsuite, &filter);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filtered);
-	kfree_at_end(test, filtered);
+	free_subsuite_at_end(test, filtered);
 
+	/* Validate we just have suite2 */
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filtered[0]);
 	KUNIT_EXPECT_STREQ(test, (const char *)filtered[0]->name, "suite2");
+	KUNIT_EXPECT_FALSE(test, filtered[1]);
+}
+
+static void filter_subsuite_test_glob_test(struct kunit *test)
+{
+	struct kunit_suite *subsuite[3] = {NULL, NULL, NULL};
+	struct kunit_suite * const *filtered;
+	struct kunit_test_filter filter = {
+		.suite_glob = "suite2",
+		.test_glob = "test2",
+	};
+
+	subsuite[0] = alloc_fake_suite(test, "suite1", dummy_test_cases);
+	subsuite[1] = alloc_fake_suite(test, "suite2", dummy_test_cases);
 
+	/* Want: suite1, suite2, NULL -> suite2 (just test1), NULL */
+	filtered = kunit_filter_subsuite(subsuite, &filter);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filtered);
+	free_subsuite_at_end(test, filtered);
+
+	/* Validate we just have suite2 */
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filtered[0]);
+	KUNIT_EXPECT_STREQ(test, (const char *)filtered[0]->name, "suite2");
 	KUNIT_EXPECT_FALSE(test, filtered[1]);
+
+	/* Now validate we just have test2 */
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filtered[0]->test_cases);
+	KUNIT_EXPECT_STREQ(test, (const char *)filtered[0]->test_cases[0].name, "test2");
+	KUNIT_EXPECT_FALSE(test, filtered[0]->test_cases[1].name);
 }
 
 static void filter_subsuite_to_empty_test(struct kunit *test)
 {
 	struct kunit_suite *subsuite[3] = {NULL, NULL, NULL};
 	struct kunit_suite * const *filtered;
+	struct kunit_test_filter filter = {
+		.suite_glob = "not_found",
+		.test_glob = NULL,
+	};
 
-	subsuite[0] = alloc_fake_suite(test, "suite1");
-	subsuite[1] = alloc_fake_suite(test, "suite2");
+	subsuite[0] = alloc_fake_suite(test, "suite1", dummy_test_cases);
+	subsuite[1] = alloc_fake_suite(test, "suite2", dummy_test_cases);
 
-	filtered = kunit_filter_subsuite(subsuite, "not_found");
-	kfree_at_end(test, filtered); /* just in case */
+	filtered = kunit_filter_subsuite(subsuite, &filter);
+	free_subsuite_at_end(test, filtered); /* just in case */
 
 	KUNIT_EXPECT_FALSE_MSG(test, filtered,
 			       "should be NULL to indicate no match");
@@ -52,7 +117,7 @@ static void kfree_subsuites_at_end(struct kunit *test, struct suite_set *suite_s
 
 	kfree_at_end(test, suite_set->start);
 	for (suites = suite_set->start; suites < suite_set->end; suites++)
-		kfree_at_end(test, *suites);
+		free_subsuite_at_end(test, *suites);
 }
 
 static void filter_suites_test(struct kunit *test)
@@ -74,8 +139,8 @@ static void filter_suites_test(struct kunit *test)
 	struct suite_set filtered = {.start = NULL, .end = NULL};
 
 	/* Emulate two files, each having one suite */
-	subsuites[0][0] = alloc_fake_suite(test, "suite0");
-	subsuites[1][0] = alloc_fake_suite(test, "suite1");
+	subsuites[0][0] = alloc_fake_suite(test, "suite0", dummy_test_cases);
+	subsuites[1][0] = alloc_fake_suite(test, "suite1", dummy_test_cases);
 
 	/* Filter out suite1 */
 	filtered = kunit_filter_suites(&suite_set, "suite0");
@@ -88,7 +153,9 @@ static void filter_suites_test(struct kunit *test)
 }
 
 static struct kunit_case executor_test_cases[] = {
+	KUNIT_CASE(parse_filter_test),
 	KUNIT_CASE(filter_subsuite_test),
+	KUNIT_CASE(filter_subsuite_test_glob_test),
 	KUNIT_CASE(filter_subsuite_to_empty_test),
 	KUNIT_CASE(filter_suites_test),
 	{}
@@ -120,14 +187,30 @@ static void kfree_at_end(struct kunit *test, const void *to_free)
 				     (void *)to_free);
 }
 
+static void free_subsuite_res_free(struct kunit_resource *res)
+{
+	kunit_free_subsuite(res->data);
+}
+
+static void free_subsuite_at_end(struct kunit *test,
+				 struct kunit_suite *const *to_free)
+{
+	if (IS_ERR_OR_NULL(to_free))
+		return;
+	kunit_alloc_and_get_resource(test, NULL, free_subsuite_res_free,
+				     GFP_KERNEL, (void *)to_free);
+}
+
 static struct kunit_suite *alloc_fake_suite(struct kunit *test,
-					    const char *suite_name)
+					    const char *suite_name,
+					    struct kunit_case *test_cases)
 {
 	struct kunit_suite *suite;
 
 	/* We normally never expect to allocate suites, hence the non-const cast. */
 	suite = kunit_kzalloc(test, sizeof(*suite), GFP_KERNEL);
 	strncpy((char *)suite->name, suite_name, sizeof(suite->name) - 1);
+	suite->test_cases = test_cases;
 
 	return suite;
 }
