RDMA/uverbs: Use a linear list to describe the compiled-in uapi

The 'tree' data structure is very hard to build at compile time, and this
makes it very limited. The new radix tree based compiler can handle a more
complex input language that does not require the compiler to perfectly
group everything into a neat tree structure.

Instead use a simple list to describe to input, where the list elements
can be of various different 'opcodes' instructing the radix compiler what
to do. Start out with opcodes chaining to other definition lists and
chaining to the existing 'tree' definition.

Replace the very top level of the 'object tree' with this list type and
get rid of struct uverbs_object_tree_def and DECLARE_UVERBS_OBJECT_TREE.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

1 files changed, 84 insertions, 59 deletions

diff --git a/drivers/infiniband/core/uverbs_uapi.c b/drivers/infiniband/core/uverbs_uapi.c
index 86f3fc5e04b4..67e8e96adb05 100644
--- a/drivers/infiniband/core/uverbs_uapi.c
+++ b/drivers/infiniband/core/uverbs_uapi.c
@@ -98,72 +98,96 @@ static int uapi_merge_method(struct uverbs_api *uapi,
 	return 0;
 }
 
-static int uapi_merge_tree(struct uverbs_api *uapi,
-			   const struct uverbs_object_tree_def *tree,
-			   bool is_driver)
+static int uapi_merge_obj_tree(struct uverbs_api *uapi,
+			       const struct uverbs_object_def *obj,
+			       bool is_driver)
 {
-	unsigned int i, j;
+	struct uverbs_api_object *obj_elm;
+	unsigned int i;
+	u32 obj_key;
 	int rc;
 
-	if (!tree->objects)
+	obj_key = uapi_key_obj(obj->id);
+	obj_elm = uapi_add_elm(uapi, obj_key, sizeof(*obj_elm));
+	if (IS_ERR(obj_elm)) {
+		if (obj_elm != ERR_PTR(-EEXIST))
+			return PTR_ERR(obj_elm);
+
+		/* This occurs when a driver uses ADD_UVERBS_METHODS */
+		if (WARN_ON(obj->type_attrs))
+			return -EINVAL;
+		obj_elm = radix_tree_lookup(&uapi->radix, obj_key);
+		if (WARN_ON(!obj_elm))
+			return -EINVAL;
+	} else {
+		obj_elm->type_attrs = obj->type_attrs;
+		if (obj->type_attrs) {
+			obj_elm->type_class = obj->type_attrs->type_class;
+			/*
+			 * Today drivers are only permitted to use idr_class
+			 * types. They cannot use FD types because we
+			 * currently have no way to revoke the fops pointer
+			 * after device disassociation.
+			 */
+			if (WARN_ON(is_driver && obj->type_attrs->type_class !=
+							 &uverbs_idr_class))
+				return -EINVAL;
+		}
+	}
+
+	if (!obj->methods)
 		return 0;
 
-	for (i = 0; i != tree->num_objects; i++) {
-		const struct uverbs_object_def *obj = (*tree->objects)[i];
-		struct uverbs_api_object *obj_elm;
-		u32 obj_key;
+	for (i = 0; i != obj->num_methods; i++) {
+		const struct uverbs_method_def *method = (*obj->methods)[i];
 
-		if (!obj)
+		if (!method)
 			continue;
 
-		obj_key = uapi_key_obj(obj->id);
-		obj_elm = uapi_add_elm(uapi, obj_key, sizeof(*obj_elm));
-		if (IS_ERR(obj_elm)) {
-			if (obj_elm != ERR_PTR(-EEXIST))
-				return PTR_ERR(obj_elm);
+		rc = uapi_merge_method(uapi, obj_elm, obj_key, method,
+				       is_driver);
+		if (rc)
+			return rc;
+	}
 
-			/* This occurs when a driver uses ADD_UVERBS_METHODS */
-			if (WARN_ON(obj->type_attrs))
-				return -EINVAL;
-			obj_elm = radix_tree_lookup(&uapi->radix, obj_key);
-			if (WARN_ON(!obj_elm))
-				return -EINVAL;
-		} else {
-			obj_elm->type_attrs = obj->type_attrs;
-			if (obj->type_attrs) {
-				obj_elm->type_class =
-					obj->type_attrs->type_class;
-				/*
-				 * Today drivers are only permitted to use
-				 * idr_class types. They cannot use FD types
-				 * because we currently have no way to revoke
-				 * the fops pointer after device
-				 * disassociation.
-				 */
-				if (WARN_ON(is_driver &&
-					    obj->type_attrs->type_class !=
-						    &uverbs_idr_class))
-					return -EINVAL;
-			}
-		}
+	return 0;
+}
+
+static int uapi_merge_def(struct uverbs_api *uapi,
+			  const struct uapi_definition *def_list,
+			  bool is_driver)
+{
+	const struct uapi_definition *def = def_list;
+	int rc;
+
+	if (!def_list)
+		return 0;
 
-		if (!obj->methods)
+	for (;; def++) {
+		switch ((enum uapi_definition_kind)def->kind) {
+		case UAPI_DEF_CHAIN:
+			rc = uapi_merge_def(uapi, def->chain, is_driver);
+			if (rc)
+				return rc;
 			continue;
 
-		for (j = 0; j != obj->num_methods; j++) {
-			const struct uverbs_method_def *method =
-				(*obj->methods)[j];
-			if (!method)
-				continue;
+		case UAPI_DEF_CHAIN_OBJ_TREE:
+			if (WARN_ON(def->object_start.object_id !=
+				    def->chain_obj_tree->id))
+				return -EINVAL;
 
-			rc = uapi_merge_method(uapi, obj_elm, obj_key, method,
-					       is_driver);
+			rc = uapi_merge_obj_tree(uapi, def->chain_obj_tree,
+						 is_driver);
 			if (rc)
 				return rc;
+			continue;
+
+		case UAPI_DEF_END:
+			return 0;
 		}
+		WARN_ON(true);
+		return -EINVAL;
 	}
-
-	return 0;
 }
 
 static int
@@ -263,9 +287,13 @@ void uverbs_destroy_api(struct uverbs_api *uapi)
 	kfree(uapi);
 }
 
-struct uverbs_api *uverbs_alloc_api(
-	const struct uverbs_object_tree_def *const *driver_specs,
-	enum rdma_driver_id driver_id)
+static const struct uapi_definition uverbs_core_api[] = {
+	UAPI_DEF_CHAIN(uverbs_def_obj_intf),
+	{},
+};
+
+struct uverbs_api *uverbs_alloc_api(const struct uapi_definition *driver_def,
+				    enum rdma_driver_id driver_id)
 {
 	struct uverbs_api *uapi;
 	int rc;
@@ -277,15 +305,12 @@ struct uverbs_api *uverbs_alloc_api(
 	INIT_RADIX_TREE(&uapi->radix, GFP_KERNEL);
 	uapi->driver_id = driver_id;
 
-	rc = uapi_merge_tree(uapi, uverbs_default_get_objects(), false);
+	rc = uapi_merge_def(uapi, uverbs_core_api, false);
+	if (rc)
+		goto err;
+	rc = uapi_merge_def(uapi, driver_def, true);
 	if (rc)
 		goto err;
-
-	for (; driver_specs && *driver_specs; driver_specs++) {
-		rc = uapi_merge_tree(uapi, *driver_specs, true);
-		if (rc)
-			goto err;
-	}
 
 	rc = uapi_finalize(uapi);
 	if (rc)