kunit: Rework kunit_resource allocation policy

KUnit's test-managed resources can be created in two ways:
- Using the kunit_add_resource() family of functions, which accept a
  struct kunit_resource pointer, typically allocated statically or on
  the stack during the test.
- Using the kunit_alloc_resource() family of functions, which allocate a
  struct kunit_resource using kzalloc() behind the scenes.

Both of these families of functions accept a 'free' function to be
called when the resource is finally disposed of.

At present, KUnit will kfree() the resource if this 'free' function is
specified, and will not if it is NULL. However, this can lead
kunit_alloc_resource() to leak memory (if no 'free' function is passed
in), or kunit_add_resource() to incorrectly kfree() memory which was
allocated by some other means (on the stack, as part of a larger
allocation, etc), if a 'free' function is provided.

Instead, always kfree() if the resource was allocated with
kunit_alloc_resource(), and never kfree() if it was passed into
kunit_add_resource() by the user. (If the user of kunit_add_resource()
wishes the resource be kfree()ed, they can call kfree() on the resource
from within the 'free' function.

This is implemented by adding a 'should_free' member to
struct kunit_resource and setting it appropriately. To facilitate this,
the various resource add/alloc functions have been refactored somewhat,
making them all call a __kunit_add_resource() helper after setting the
'should_free' member appropriately. In the process, all other functions
have been made static inline functions.

Signed-off-by: David Gow <davidgow@google.com>
Tested-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 7 insertions, 57 deletions

diff --git a/lib/kunit/resource.c b/lib/kunit/resource.c
index b3ba0d98d89e..c414df922f34 100644
--- a/lib/kunit/resource.c
+++ b/lib/kunit/resource.c
@@ -14,13 +14,13 @@
  * Used for static resources and when a kunit_resource * has been created by
  * kunit_alloc_resource().  When an init function is supplied, @data is passed
  * into the init function; otherwise, we simply set the resource data field to
- * the data value passed in.
+ * the data value passed in. Doesn't initialize res->should_kfree.
  */
-int kunit_add_resource(struct kunit *test,
-		       kunit_resource_init_t init,
-		       kunit_resource_free_t free,
-		       struct kunit_resource *res,
-		       void *data)
+int __kunit_add_resource(struct kunit *test,
+			 kunit_resource_init_t init,
+			 kunit_resource_free_t free,
+			 struct kunit_resource *res,
+			 void *data)
 {
 	int ret = 0;
 	unsigned long flags;
@@ -43,57 +43,7 @@ int kunit_add_resource(struct kunit *test,
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(kunit_add_resource);
-
-int kunit_add_named_resource(struct kunit *test,
-			     kunit_resource_init_t init,
-			     kunit_resource_free_t free,
-			     struct kunit_resource *res,
-			     const char *name,
-			     void *data)
-{
-	struct kunit_resource *existing;
-
-	if (!name)
-		return -EINVAL;
-
-	existing = kunit_find_named_resource(test, name);
-	if (existing) {
-		kunit_put_resource(existing);
-		return -EEXIST;
-	}
-
-	res->name = name;
-
-	return kunit_add_resource(test, init, free, res, data);
-}
-EXPORT_SYMBOL_GPL(kunit_add_named_resource);
-
-struct kunit_resource *kunit_alloc_and_get_resource(struct kunit *test,
-						    kunit_resource_init_t init,
-						    kunit_resource_free_t free,
-						    gfp_t internal_gfp,
-						    void *data)
-{
-	struct kunit_resource *res;
-	int ret;
-
-	res = kzalloc(sizeof(*res), internal_gfp);
-	if (!res)
-		return NULL;
-
-	ret = kunit_add_resource(test, init, free, res, data);
-	if (!ret) {
-		/*
-		 * bump refcount for get; kunit_resource_put() should be called
-		 * when done.
-		 */
-		kunit_get_resource(res);
-		return res;
-	}
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(kunit_alloc_and_get_resource);
+EXPORT_SYMBOL_GPL(__kunit_add_resource);
 
 void kunit_remove_resource(struct kunit *test, struct kunit_resource *res)
 {