kunit: string-stream: Simplify resource use

Currently, KUnit's string streams are themselves "KUnit resources".
This is redundant since the stream itself is already allocated with
kunit_kzalloc() and will thus be freed automatically at the end of the
test.

string-stream is only used internally within KUnit, and isn't using the
extra features that resources provide like reference counting, being
able to locate them dynamically as "test-local variables", etc.

Indeed, the resource's refcount is never incremented when the
pointer is returned. The fact that it's always manually destroyed is
more evidence that the reference counting is unused.

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

lib/kunit/string-stream.c

@@ -12,64 +12,31 @@
 
 #include "string-stream.h"
 
-struct string_stream_fragment_alloc_context {
-	struct kunit *test;
-	int len;
-	gfp_t gfp;
-};
 
-static int string_stream_fragment_init(struct kunit_resource *res,
-				       void *context)
+static struct string_stream_fragment *alloc_string_stream_fragment(
+		struct kunit *test, int len, gfp_t gfp)
 {
-	struct string_stream_fragment_alloc_context *ctx = context;
 	struct string_stream_fragment *frag;
 
-	frag = kunit_kzalloc(ctx->test, sizeof(*frag), ctx->gfp);
+	frag = kunit_kzalloc(test, sizeof(*frag), gfp);
 	if (!frag)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
-	frag->test = ctx->test;
-	frag->fragment = kunit_kmalloc(ctx->test, ctx->len, ctx->gfp);
+	frag->test = test;
+	frag->fragment = kunit_kmalloc(test, len, gfp);
 	if (!frag->fragment)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
-	res->data = frag;
-
-	return 0;
+	return frag;
 }
 
-static void string_stream_fragment_free(struct kunit_resource *res)
+static void string_stream_fragment_destroy(struct string_stream_fragment *frag)
 {
-	struct string_stream_fragment *frag = res->data;
-
 	list_del(&frag->node);
 	kunit_kfree(frag->test, frag->fragment);
 	kunit_kfree(frag->test, frag);
 }
 
-static struct string_stream_fragment *alloc_string_stream_fragment(
-		struct kunit *test, int len, gfp_t gfp)
-{
-	struct string_stream_fragment_alloc_context context = {
-		.test = test,
-		.len = len,
-		.gfp = gfp
-	};
-
-	return kunit_alloc_resource(test,
-				    string_stream_fragment_init,
-				    string_stream_fragment_free,
-				    gfp,
-				    &context);
-}
-
-static int string_stream_fragment_destroy(struct string_stream_fragment *frag)
-{
-	return kunit_destroy_resource(frag->test,
-				      kunit_resource_instance_match,
-				      frag);
-}
-
 int string_stream_vadd(struct string_stream *stream,
 		       const char *fmt,
 		       va_list args)
@@ -169,48 +136,23 @@ struct string_stream_alloc_context {
 	gfp_t gfp;
 };
 
-static int string_stream_init(struct kunit_resource *res, void *context)
+struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp)
 {
 	struct string_stream *stream;
-	struct string_stream_alloc_context *ctx = context;
 
-	stream = kunit_kzalloc(ctx->test, sizeof(*stream), ctx->gfp);
+	stream = kunit_kzalloc(test, sizeof(*stream), gfp);
 	if (!stream)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
-	res->data = stream;
-	stream->gfp = ctx->gfp;
-	stream->test = ctx->test;
+	stream->gfp = gfp;
+	stream->test = test;
 	INIT_LIST_HEAD(&stream->fragments);
 	spin_lock_init(&stream->lock);
 
-	return 0;
+	return stream;
 }
 
-static void string_stream_free(struct kunit_resource *res)
+void string_stream_destroy(struct string_stream *stream)
 {
-	struct string_stream *stream = res->data;
-
 	string_stream_clear(stream);
 }
-
-struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp)
-{
-	struct string_stream_alloc_context context = {
-		.test = test,
-		.gfp = gfp
-	};
-
-	return kunit_alloc_resource(test,
-				    string_stream_init,
-				    string_stream_free,
-				    gfp,
-				    &context);
-}
-
-int string_stream_destroy(struct string_stream *stream)
-{
-	return kunit_destroy_resource(stream->test,
-				      kunit_resource_instance_match,
-				      stream);
-}

lib/kunit/string-stream.h

@@ -46,6 +46,6 @@ int string_stream_append(struct string_stream *stream,
 
 bool string_stream_is_empty(struct string_stream *stream);
 
-int string_stream_destroy(struct string_stream *stream);
+void string_stream_destroy(struct string_stream *stream);
 
 #endif /* _KUNIT_STRING_STREAM_H */

lib/kunit/test.c

@@ -278,7 +278,7 @@ static void kunit_fail(struct kunit *test, const struct kunit_loc *loc,
 
 	kunit_print_string_stream(test, stream);
 
-	WARN_ON(string_stream_destroy(stream));
+	string_stream_destroy(stream);
 }
 
 static void __noreturn kunit_abort(struct kunit *test)