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>

4 files changed, 108 insertions, 85 deletions

diff --git a/drivers/infiniband/core/rdma_core.h b/drivers/infiniband/core/rdma_core.h
index 4886d2bba7c7..e39e9da1ff71 100644
--- a/drivers/infiniband/core/rdma_core.h
+++ b/drivers/infiniband/core/rdma_core.h
@@ -152,9 +152,8 @@ uapi_get_object(struct uverbs_api *uapi, u16 object_id)
 }
 
 char *uapi_key_format(char *S, unsigned int key);
-struct uverbs_api *uverbs_alloc_api(
-	const struct uverbs_object_tree_def *const *driver_specs,
-	enum rdma_driver_id driver_id);
+struct uverbs_api *uverbs_alloc_api(const struct uapi_definition *driver_def,
+				    enum rdma_driver_id driver_id);
 void uverbs_disassociate_api_pre(struct ib_uverbs_device *uverbs_dev);
 void uverbs_disassociate_api(struct uverbs_api *uapi);
 void uverbs_destroy_api(struct uverbs_api *uapi);
@@ -162,4 +161,6 @@ void uapi_compute_bundle_size(struct uverbs_api_ioctl_method *method_elm,
 			      unsigned int num_attrs);
 void uverbs_user_mmap_disassociate(struct ib_uverbs_file *ufile);
 
+extern const struct uapi_definition uverbs_def_obj_intf[];
+
 #endif /* RDMA_CORE_H */
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 6d373f5515b7..9a3b88d0095a 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -1224,7 +1224,7 @@ static int ib_uverbs_create_uapi(struct ib_device *device,
 {
 	struct uverbs_api *uapi;
 
-	uapi = uverbs_alloc_api(device->driver_specs, device->driver_id);
+	uapi = uverbs_alloc_api(device->driver_def, device->driver_id);
 	if (IS_ERR(uapi))
 		return PTR_ERR(uapi);
 
diff --git a/drivers/infiniband/core/uverbs_std_types.c b/drivers/infiniband/core/uverbs_std_types.c
index 203cc96ac6f5..2db188ed825f 100644
--- a/drivers/infiniband/core/uverbs_std_types.c
+++ b/drivers/infiniband/core/uverbs_std_types.c
@@ -262,25 +262,22 @@ DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_PD,
 
 DECLARE_UVERBS_GLOBAL_METHODS(UVERBS_OBJECT_DEVICE);
 
-DECLARE_UVERBS_OBJECT_TREE(uverbs_default_objects,
-			   &UVERBS_OBJECT(UVERBS_OBJECT_DEVICE),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_PD),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_MR),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_COMP_CHANNEL),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_CQ),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_QP),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_AH),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_MW),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_SRQ),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_FLOW),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_WQ),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_RWQ_IND_TBL),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_XRCD),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_FLOW_ACTION),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_DM),
-			   &UVERBS_OBJECT(UVERBS_OBJECT_COUNTERS));
-
-const struct uverbs_object_tree_def *uverbs_default_get_objects(void)
-{
-	return &uverbs_default_objects;
-}
+const struct uapi_definition uverbs_def_obj_intf[] = {
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_DEVICE),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_PD),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_MR),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_COMP_CHANNEL),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_CQ),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_QP),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_AH),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_MW),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_SRQ),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_FLOW),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_WQ),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_RWQ_IND_TBL),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_XRCD),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_FLOW_ACTION),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_DM),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_COUNTERS),
+	{}
+};
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)