[PATCH v1 3/3] kunit: kmalloc_array: Use kunit_add_action()

[David Gow <davidgow@google.com>]

The kunit_add_action() function is much simpler and cleaner to use that
the full KUnit resource API for simple things like the
kunit_kmalloc_array() functionality.

Replacing it allows us to get rid of a number of helper functions, and
leaves us with no uses of kunit_alloc_resource(), which has some
usability problems and is going to have its behaviour modified in an
upcoming patch.

Note that we need to use kunit_release_action() to implement kunit_kfree().

Signed-off-by: David Gow <davidgow@google.com>
---

Changes since RFCv2:
https://lore.kernel.org/linux-kselftest/20230331080411.981038-4-davidgow@google.com/
- Update to match changes in the the action API.
- Always allocate the action context with GFP_KERNEL.
- Update documentation to note that this will cause GFP_KERNEL
  allocations, regardless of the gfp argument passed in.

---
 include/kunit/test.h | 10 +++++++--
 lib/kunit/test.c     | 48 +++++++++-----------------------------------
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 57b309c6ca27..3e8e98d0d8b1 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -321,8 +321,11 @@ enum kunit_status kunit_suite_has_succeeded(struct kunit_suite *suite);
  * @gfp: flags passed to underlying kmalloc().
  *
  * Just like `kmalloc_array(...)`, except the allocation is managed by the test case
- * and is automatically cleaned up after the test case concludes. See &struct
- * kunit_resource for more information.
+ * and is automatically cleaned up after the test case concludes. See kunit_add_action()
+ * for more information.
+ *
+ * Note that some internal context data is also allocated with GFP_KERNEL,
+ * regardless of the gfp passed in.
  */
 void *kunit_kmalloc_array(struct kunit *test, size_t n, size_t size, gfp_t gfp);
 
@@ -333,6 +336,9 @@ void *kunit_kmalloc_array(struct kunit *test, size_t n, size_t size, gfp_t gfp);
  * @gfp: flags passed to underlying kmalloc().
  *
  * See kmalloc() and kunit_kmalloc_array() for more information.
+ *
+ * Note that some internal context data is also allocated with GFP_KERNEL,
+ * regardless of the gfp passed in.
  */
 static inline void *kunit_kmalloc(struct kunit *test, size_t size, gfp_t gfp)
 {
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index e2910b261112..6aafe2138766 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -712,58 +712,28 @@ static struct notifier_block kunit_mod_nb = {
 };
 #endif
 
-struct kunit_kmalloc_array_params {
-	size_t n;
-	size_t size;
-	gfp_t gfp;
-};
-
-static int kunit_kmalloc_array_init(struct kunit_resource *res, void *context)
+void *kunit_kmalloc_array(struct kunit *test, size_t n, size_t size, gfp_t gfp)
 {
-	struct kunit_kmalloc_array_params *params = context;
+	void *data;
 
-	res->data = kmalloc_array(params->n, params->size, params->gfp);
-	if (!res->data)
-		return -ENOMEM;
+	data = kmalloc_array(n, size, gfp);
 
-	return 0;
-}
+	if (!data)
+		return NULL;
 
-static void kunit_kmalloc_array_free(struct kunit_resource *res)
-{
-	kfree(res->data);
-}
+	if (kunit_add_action_or_reset(test, (void (*)(void *))kfree, data) != 0)
+		return NULL;
 
-void *kunit_kmalloc_array(struct kunit *test, size_t n, size_t size, gfp_t gfp)
-{
-	struct kunit_kmalloc_array_params params = {
-		.size = size,
-		.n = n,
-		.gfp = gfp
-	};
-
-	return kunit_alloc_resource(test,
-				    kunit_kmalloc_array_init,
-				    kunit_kmalloc_array_free,
-				    gfp,
-				    &params);
+	return data;
 }
 EXPORT_SYMBOL_GPL(kunit_kmalloc_array);
 
-static inline bool kunit_kfree_match(struct kunit *test,
-				     struct kunit_resource *res, void *match_data)
-{
-	/* Only match resources allocated with kunit_kmalloc() and friends. */
-	return res->free == kunit_kmalloc_array_free && res->data == match_data;
-}
-
 void kunit_kfree(struct kunit *test, const void *ptr)
 {
 	if (!ptr)
 		return;
 
-	if (kunit_destroy_resource(test, kunit_kfree_match, (void *)ptr))
-		KUNIT_FAIL(test, "kunit_kfree: %px already freed or not allocated by kunit", ptr);
+	kunit_release_action(test, (void (*)(void *))kfree, (void *)ptr);
 }
 EXPORT_SYMBOL_GPL(kunit_kfree);
 
-- 
2.40.0.634.g4ca3ef3211-goog