1 files changed, 734 insertions, 0 deletions

diff --git a/drivers/infiniband/core/uverbs_uapi.c b/drivers/infiniband/core/uverbs_uapi.c
new file mode 100644
index 000000000..a02916a3a
--- /dev/null
+++ b/drivers/infiniband/core/uverbs_uapi.c
@@ -0,0 +1,734 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2017, Mellanox Technologies inc.  All rights reserved.
+ */
+#include <rdma/uverbs_ioctl.h>
+#include <rdma/rdma_user_ioctl.h>
+#include <linux/bitops.h>
+#include "rdma_core.h"
+#include "uverbs.h"
+
+static int ib_uverbs_notsupp(struct uverbs_attr_bundle *attrs)
+{
+	return -EOPNOTSUPP;
+}
+
+static void *uapi_add_elm(struct uverbs_api *uapi, u32 key, size_t alloc_size)
+{
+	void *elm;
+	int rc;
+
+	if (key == UVERBS_API_KEY_ERR)
+		return ERR_PTR(-EOVERFLOW);
+
+	elm = kzalloc(alloc_size, GFP_KERNEL);
+	if (!elm)
+		return ERR_PTR(-ENOMEM);
+	rc = radix_tree_insert(&uapi->radix, key, elm);
+	if (rc) {
+		kfree(elm);
+		return ERR_PTR(rc);
+	}
+
+	return elm;
+}
+
+static void *uapi_add_get_elm(struct uverbs_api *uapi, u32 key,
+			      size_t alloc_size, bool *exists)
+{
+	void *elm;
+
+	elm = uapi_add_elm(uapi, key, alloc_size);
+	if (!IS_ERR(elm)) {
+		*exists = false;
+		return elm;
+	}
+
+	if (elm != ERR_PTR(-EEXIST))
+		return elm;
+
+	elm = radix_tree_lookup(&uapi->radix, key);
+	if (WARN_ON(!elm))
+		return ERR_PTR(-EINVAL);
+	*exists = true;
+	return elm;
+}
+
+static int uapi_create_write(struct uverbs_api *uapi,
+			     struct ib_device *ibdev,
+			     const struct uapi_definition *def,
+			     u32 obj_key,
+			     u32 *cur_method_key)
+{
+	struct uverbs_api_write_method *method_elm;
+	u32 method_key = obj_key;
+	bool exists;
+
+	if (def->write.is_ex)
+		method_key |= uapi_key_write_ex_method(def->write.command_num);
+	else
+		method_key |= uapi_key_write_method(def->write.command_num);
+
+	method_elm = uapi_add_get_elm(uapi, method_key, sizeof(*method_elm),
+				      &exists);
+	if (IS_ERR(method_elm))
+		return PTR_ERR(method_elm);
+
+	if (WARN_ON(exists && (def->write.is_ex != method_elm->is_ex)))
+		return -EINVAL;
+
+	method_elm->is_ex = def->write.is_ex;
+	method_elm->handler = def->func_write;
+	if (!def->write.is_ex)
+		method_elm->disabled = !(ibdev->uverbs_cmd_mask &
+					 BIT_ULL(def->write.command_num));
+
+	if (!def->write.is_ex && def->func_write) {
+		method_elm->has_udata = def->write.has_udata;
+		method_elm->has_resp = def->write.has_resp;
+		method_elm->req_size = def->write.req_size;
+		method_elm->resp_size = def->write.resp_size;
+	}
+
+	*cur_method_key = method_key;
+	return 0;
+}
+
+static int uapi_merge_method(struct uverbs_api *uapi,
+			     struct uverbs_api_object *obj_elm, u32 obj_key,
+			     const struct uverbs_method_def *method,
+			     bool is_driver)
+{
+	u32 method_key = obj_key | uapi_key_ioctl_method(method->id);
+	struct uverbs_api_ioctl_method *method_elm;
+	unsigned int i;
+	bool exists;
+
+	if (!method->attrs)
+		return 0;
+
+	method_elm = uapi_add_get_elm(uapi, method_key, sizeof(*method_elm),
+				      &exists);
+	if (IS_ERR(method_elm))
+		return PTR_ERR(method_elm);
+	if (exists) {
+		/*
+		 * This occurs when a driver uses ADD_UVERBS_ATTRIBUTES_SIMPLE
+		 */
+		if (WARN_ON(method->handler))
+			return -EINVAL;
+	} else {
+		WARN_ON(!method->handler);
+		rcu_assign_pointer(method_elm->handler, method->handler);
+		if (method->handler != uverbs_destroy_def_handler)
+			method_elm->driver_method = is_driver;
+	}
+
+	for (i = 0; i != method->num_attrs; i++) {
+		const struct uverbs_attr_def *attr = (*method->attrs)[i];
+		struct uverbs_api_attr *attr_slot;
+
+		if (!attr)
+			continue;
+
+		/*
+		 * ENUM_IN contains the 'ids' pointer to the driver's .rodata,
+		 * so if it is specified by a driver then it always makes this
+		 * into a driver method.
+		 */
+		if (attr->attr.type == UVERBS_ATTR_TYPE_ENUM_IN)
+			method_elm->driver_method |= is_driver;
+
+		/*
+		 * Like other uobject based things we only support a single
+		 * uobject being NEW'd or DESTROY'd
+		 */
+		if (attr->attr.type == UVERBS_ATTR_TYPE_IDRS_ARRAY) {
+			u8 access = attr->attr.u2.objs_arr.access;
+
+			if (WARN_ON(access == UVERBS_ACCESS_NEW ||
+				    access == UVERBS_ACCESS_DESTROY))
+				return -EINVAL;
+		}
+
+		attr_slot =
+			uapi_add_elm(uapi, method_key | uapi_key_attr(attr->id),
+				     sizeof(*attr_slot));
+		/* Attributes are not allowed to be modified by drivers */
+		if (IS_ERR(attr_slot))
+			return PTR_ERR(attr_slot);
+
+		attr_slot->spec = attr->attr;
+	}
+
+	return 0;
+}
+
+static int uapi_merge_obj_tree(struct uverbs_api *uapi,
+			       const struct uverbs_object_def *obj,
+			       bool is_driver)
+{
+	struct uverbs_api_object *obj_elm;
+	unsigned int i;
+	u32 obj_key;
+	bool exists;
+	int rc;
+
+	obj_key = uapi_key_obj(obj->id);
+	obj_elm = uapi_add_get_elm(uapi, obj_key, sizeof(*obj_elm), &exists);
+	if (IS_ERR(obj_elm))
+		return PTR_ERR(obj_elm);
+
+	if (obj->type_attrs) {
+		if (WARN_ON(obj_elm->type_attrs))
+			return -EINVAL;
+
+		obj_elm->id = obj->id;
+		obj_elm->type_attrs = obj->type_attrs;
+		obj_elm->type_class = obj->type_attrs->type_class;
+		/*
+		 * Today drivers are only permitted to use idr_class and
+		 * fd_class types. We can revoke the IDR types during
+		 * disassociation, and the FD types require the driver to use
+		 * struct file_operations.owner to prevent the driver module
+		 * code from unloading while the file is open. This provides
+		 * enough safety that uverbs_uobject_fd_release() will
+		 * continue to work.  Drivers using FD are responsible to
+		 * handle disassociation of the device on their own.
+		 */
+		if (WARN_ON(is_driver &&
+			    obj->type_attrs->type_class != &uverbs_idr_class &&
+			    obj->type_attrs->type_class != &uverbs_fd_class))
+			return -EINVAL;
+	}
+
+	if (!obj->methods)
+		return 0;
+
+	for (i = 0; i != obj->num_methods; i++) {
+		const struct uverbs_method_def *method = (*obj->methods)[i];
+
+		if (!method)
+			continue;
+
+		rc = uapi_merge_method(uapi, obj_elm, obj_key, method,
+				       is_driver);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+static int uapi_disable_elm(struct uverbs_api *uapi,
+			    const struct uapi_definition *def,
+			    u32 obj_key,
+			    u32 method_key)
+{
+	bool exists;
+
+	if (def->scope == UAPI_SCOPE_OBJECT) {
+		struct uverbs_api_object *obj_elm;
+
+		obj_elm = uapi_add_get_elm(
+			uapi, obj_key, sizeof(*obj_elm), &exists);
+		if (IS_ERR(obj_elm))
+			return PTR_ERR(obj_elm);
+		obj_elm->disabled = 1;
+		return 0;
+	}
+
+	if (def->scope == UAPI_SCOPE_METHOD &&
+	    uapi_key_is_ioctl_method(method_key)) {
+		struct uverbs_api_ioctl_method *method_elm;
+
+		method_elm = uapi_add_get_elm(uapi, method_key,
+					      sizeof(*method_elm), &exists);
+		if (IS_ERR(method_elm))
+			return PTR_ERR(method_elm);
+		method_elm->disabled = 1;
+		return 0;
+	}
+
+	if (def->scope == UAPI_SCOPE_METHOD &&
+	    (uapi_key_is_write_method(method_key) ||
+	     uapi_key_is_write_ex_method(method_key))) {
+		struct uverbs_api_write_method *write_elm;
+
+		write_elm = uapi_add_get_elm(uapi, method_key,
+					     sizeof(*write_elm), &exists);
+		if (IS_ERR(write_elm))
+			return PTR_ERR(write_elm);
+		write_elm->disabled = 1;
+		return 0;
+	}
+
+	WARN_ON(true);
+	return -EINVAL;
+}
+
+static int uapi_merge_def(struct uverbs_api *uapi, struct ib_device *ibdev,
+			  const struct uapi_definition *def_list,
+			  bool is_driver)
+{
+	const struct uapi_definition *def = def_list;
+	u32 cur_obj_key = UVERBS_API_KEY_ERR;
+	u32 cur_method_key = UVERBS_API_KEY_ERR;
+	bool exists;
+	int rc;
+
+	if (!def_list)
+		return 0;
+
+	for (;; def++) {
+		switch ((enum uapi_definition_kind)def->kind) {
+		case UAPI_DEF_CHAIN:
+			rc = uapi_merge_def(uapi, ibdev, def->chain, is_driver);
+			if (rc)
+				return rc;
+			continue;
+
+		case UAPI_DEF_CHAIN_OBJ_TREE:
+			if (WARN_ON(def->object_start.object_id !=
+				    def->chain_obj_tree->id))
+				return -EINVAL;
+
+			cur_obj_key = uapi_key_obj(def->object_start.object_id);
+			rc = uapi_merge_obj_tree(uapi, def->chain_obj_tree,
+						 is_driver);
+			if (rc)
+				return rc;
+			continue;
+
+		case UAPI_DEF_END:
+			return 0;
+
+		case UAPI_DEF_IS_SUPPORTED_DEV_FN: {
+			void **ibdev_fn =
+				(void *)(&ibdev->ops) + def->needs_fn_offset;
+
+			if (*ibdev_fn)
+				continue;
+			rc = uapi_disable_elm(
+				uapi, def, cur_obj_key, cur_method_key);
+			if (rc)
+				return rc;
+			continue;
+		}
+
+		case UAPI_DEF_IS_SUPPORTED_FUNC:
+			if (def->func_is_supported(ibdev))
+				continue;
+			rc = uapi_disable_elm(
+				uapi, def, cur_obj_key, cur_method_key);
+			if (rc)
+				return rc;
+			continue;
+
+		case UAPI_DEF_OBJECT_START: {
+			struct uverbs_api_object *obj_elm;
+
+			cur_obj_key = uapi_key_obj(def->object_start.object_id);
+			obj_elm = uapi_add_get_elm(uapi, cur_obj_key,
+						   sizeof(*obj_elm), &exists);
+			if (IS_ERR(obj_elm))
+				return PTR_ERR(obj_elm);
+			continue;
+		}
+
+		case UAPI_DEF_WRITE:
+			rc = uapi_create_write(
+				uapi, ibdev, def, cur_obj_key, &cur_method_key);
+			if (rc)
+				return rc;
+			continue;
+		}
+		WARN_ON(true);
+		return -EINVAL;
+	}
+}
+
+static int
+uapi_finalize_ioctl_method(struct uverbs_api *uapi,
+			   struct uverbs_api_ioctl_method *method_elm,
+			   u32 method_key)
+{
+	struct radix_tree_iter iter;
+	unsigned int num_attrs = 0;
+	unsigned int max_bkey = 0;
+	bool single_uobj = false;
+	void __rcu **slot;
+
+	method_elm->destroy_bkey = UVERBS_API_ATTR_BKEY_LEN;
+	radix_tree_for_each_slot (slot, &uapi->radix, &iter,
+				  uapi_key_attrs_start(method_key)) {
+		struct uverbs_api_attr *elm =
+			rcu_dereference_protected(*slot, true);
+		u32 attr_key = iter.index & UVERBS_API_ATTR_KEY_MASK;
+		u32 attr_bkey = uapi_bkey_attr(attr_key);
+		u8 type = elm->spec.type;
+
+		if (uapi_key_attr_to_ioctl_method(iter.index) !=
+		    uapi_key_attr_to_ioctl_method(method_key))
+			break;
+
+		if (elm->spec.mandatory)
+			__set_bit(attr_bkey, method_elm->attr_mandatory);
+
+		if (elm->spec.is_udata)
+			method_elm->has_udata = true;
+
+		if (type == UVERBS_ATTR_TYPE_IDR ||
+		    type == UVERBS_ATTR_TYPE_FD) {
+			u8 access = elm->spec.u.obj.access;
+
+			/*
+			 * Verbs specs may only have one NEW/DESTROY, we don't
+			 * have the infrastructure to abort multiple NEW's or
+			 * cope with multiple DESTROY failure.
+			 */
+			if (access == UVERBS_ACCESS_NEW ||
+			    access == UVERBS_ACCESS_DESTROY) {
+				if (WARN_ON(single_uobj))
+					return -EINVAL;
+
+				single_uobj = true;
+				if (WARN_ON(!elm->spec.mandatory))
+					return -EINVAL;
+			}
+
+			if (access == UVERBS_ACCESS_DESTROY)
+				method_elm->destroy_bkey = attr_bkey;
+		}
+
+		max_bkey = max(max_bkey, attr_bkey);
+		num_attrs++;
+	}
+
+	method_elm->key_bitmap_len = max_bkey + 1;
+	WARN_ON(method_elm->key_bitmap_len > UVERBS_API_ATTR_BKEY_LEN);
+
+	uapi_compute_bundle_size(method_elm, num_attrs);
+	return 0;
+}
+
+static int uapi_finalize(struct uverbs_api *uapi)
+{
+	const struct uverbs_api_write_method **data;
+	unsigned long max_write_ex = 0;
+	unsigned long max_write = 0;
+	struct radix_tree_iter iter;
+	void __rcu **slot;
+	int rc;
+	int i;
+
+	radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
+		struct uverbs_api_ioctl_method *method_elm =
+			rcu_dereference_protected(*slot, true);
+
+		if (uapi_key_is_ioctl_method(iter.index)) {
+			rc = uapi_finalize_ioctl_method(uapi, method_elm,
+							iter.index);
+			if (rc)
+				return rc;
+		}
+
+		if (uapi_key_is_write_method(iter.index))
+			max_write = max(max_write,
+					iter.index & UVERBS_API_ATTR_KEY_MASK);
+		if (uapi_key_is_write_ex_method(iter.index))
+			max_write_ex =
+				max(max_write_ex,
+				    iter.index & UVERBS_API_ATTR_KEY_MASK);
+	}
+
+	uapi->notsupp_method.handler = ib_uverbs_notsupp;
+	uapi->num_write = max_write + 1;
+	uapi->num_write_ex = max_write_ex + 1;
+	data = kmalloc_array(uapi->num_write + uapi->num_write_ex,
+			     sizeof(*uapi->write_methods), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	for (i = 0; i != uapi->num_write + uapi->num_write_ex; i++)
+		data[i] = &uapi->notsupp_method;
+	uapi->write_methods = data;
+	uapi->write_ex_methods = data + uapi->num_write;
+
+	radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
+		if (uapi_key_is_write_method(iter.index))
+			uapi->write_methods[iter.index &
+					    UVERBS_API_ATTR_KEY_MASK] =
+				rcu_dereference_protected(*slot, true);
+		if (uapi_key_is_write_ex_method(iter.index))
+			uapi->write_ex_methods[iter.index &
+					       UVERBS_API_ATTR_KEY_MASK] =
+				rcu_dereference_protected(*slot, true);
+	}
+
+	return 0;
+}
+
+static void uapi_remove_range(struct uverbs_api *uapi, u32 start, u32 last)
+{
+	struct radix_tree_iter iter;
+	void __rcu **slot;
+
+	radix_tree_for_each_slot (slot, &uapi->radix, &iter, start) {
+		if (iter.index > last)
+			return;
+		kfree(rcu_dereference_protected(*slot, true));
+		radix_tree_iter_delete(&uapi->radix, &iter, slot);
+	}
+}
+
+static void uapi_remove_object(struct uverbs_api *uapi, u32 obj_key)
+{
+	uapi_remove_range(uapi, obj_key,
+			  obj_key | UVERBS_API_METHOD_KEY_MASK |
+				  UVERBS_API_ATTR_KEY_MASK);
+}
+
+static void uapi_remove_method(struct uverbs_api *uapi, u32 method_key)
+{
+	uapi_remove_range(uapi, method_key,
+			  method_key | UVERBS_API_ATTR_KEY_MASK);
+}
+
+
+static u32 uapi_get_obj_id(struct uverbs_attr_spec *spec)
+{
+	if (spec->type == UVERBS_ATTR_TYPE_IDR ||
+	    spec->type == UVERBS_ATTR_TYPE_FD)
+		return spec->u.obj.obj_type;
+	if (spec->type == UVERBS_ATTR_TYPE_IDRS_ARRAY)
+		return spec->u2.objs_arr.obj_type;
+	return UVERBS_API_KEY_ERR;
+}
+
+static void uapi_key_okay(u32 key)
+{
+	unsigned int count = 0;
+
+	if (uapi_key_is_object(key))
+		count++;
+	if (uapi_key_is_ioctl_method(key))
+		count++;
+	if (uapi_key_is_write_method(key))
+		count++;
+	if (uapi_key_is_write_ex_method(key))
+		count++;
+	if (uapi_key_is_attr(key))
+		count++;
+	WARN(count != 1, "Bad count %u key=%x", count, key);
+}
+
+static void uapi_finalize_disable(struct uverbs_api *uapi)
+{
+	struct radix_tree_iter iter;
+	u32 starting_key = 0;
+	bool scan_again = false;
+	void __rcu **slot;
+
+again:
+	radix_tree_for_each_slot (slot, &uapi->radix, &iter, starting_key) {
+		uapi_key_okay(iter.index);
+
+		if (uapi_key_is_object(iter.index)) {
+			struct uverbs_api_object *obj_elm =
+				rcu_dereference_protected(*slot, true);
+
+			if (obj_elm->disabled) {
+				/* Have to check all the attrs again */
+				scan_again = true;
+				starting_key = iter.index;
+				uapi_remove_object(uapi, iter.index);
+				goto again;
+			}
+			continue;
+		}
+
+		if (uapi_key_is_ioctl_method(iter.index)) {
+			struct uverbs_api_ioctl_method *method_elm =
+				rcu_dereference_protected(*slot, true);
+
+			if (method_elm->disabled) {
+				starting_key = iter.index;
+				uapi_remove_method(uapi, iter.index);
+				goto again;
+			}
+			continue;
+		}
+
+		if (uapi_key_is_write_method(iter.index) ||
+		    uapi_key_is_write_ex_method(iter.index)) {
+			struct uverbs_api_write_method *method_elm =
+				rcu_dereference_protected(*slot, true);
+
+			if (method_elm->disabled) {
+				kfree(method_elm);
+				radix_tree_iter_delete(&uapi->radix, &iter, slot);
+			}
+			continue;
+		}
+
+		if (uapi_key_is_attr(iter.index)) {
+			struct uverbs_api_attr *attr_elm =
+				rcu_dereference_protected(*slot, true);
+			const struct uverbs_api_object *tmp_obj;
+			u32 obj_key;
+
+			/*
+			 * If the method has a mandatory object handle
+			 * attribute which relies on an object which is not
+			 * present then the entire method is uncallable.
+			 */
+			if (!attr_elm->spec.mandatory)
+				continue;
+			obj_key = uapi_get_obj_id(&attr_elm->spec);
+			if (obj_key == UVERBS_API_KEY_ERR)
+				continue;
+			tmp_obj = uapi_get_object(uapi, obj_key);
+			if (IS_ERR(tmp_obj)) {
+				if (PTR_ERR(tmp_obj) == -ENOMSG)
+					continue;
+			} else {
+				if (!tmp_obj->disabled)
+					continue;
+			}
+
+			starting_key = iter.index;
+			uapi_remove_method(
+				uapi,
+				iter.index & (UVERBS_API_OBJ_KEY_MASK |
+					      UVERBS_API_METHOD_KEY_MASK));
+			goto again;
+		}
+
+		WARN_ON(false);
+	}
+
+	if (!scan_again)
+		return;
+	scan_again = false;
+	starting_key = 0;
+	goto again;
+}
+
+void uverbs_destroy_api(struct uverbs_api *uapi)
+{
+	if (!uapi)
+		return;
+
+	uapi_remove_range(uapi, 0, U32_MAX);
+	kfree(uapi->write_methods);
+	kfree(uapi);
+}
+
+static const struct uapi_definition uverbs_core_api[] = {
+	UAPI_DEF_CHAIN(uverbs_def_obj_async_fd),
+	UAPI_DEF_CHAIN(uverbs_def_obj_counters),
+	UAPI_DEF_CHAIN(uverbs_def_obj_cq),
+	UAPI_DEF_CHAIN(uverbs_def_obj_device),
+	UAPI_DEF_CHAIN(uverbs_def_obj_dm),
+	UAPI_DEF_CHAIN(uverbs_def_obj_flow_action),
+	UAPI_DEF_CHAIN(uverbs_def_obj_intf),
+	UAPI_DEF_CHAIN(uverbs_def_obj_mr),
+	UAPI_DEF_CHAIN(uverbs_def_obj_qp),
+	UAPI_DEF_CHAIN(uverbs_def_obj_srq),
+	UAPI_DEF_CHAIN(uverbs_def_obj_wq),
+	UAPI_DEF_CHAIN(uverbs_def_write_intf),
+	{},
+};
+
+struct uverbs_api *uverbs_alloc_api(struct ib_device *ibdev)
+{
+	struct uverbs_api *uapi;
+	int rc;
+
+	uapi = kzalloc(sizeof(*uapi), GFP_KERNEL);
+	if (!uapi)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_RADIX_TREE(&uapi->radix, GFP_KERNEL);
+	uapi->driver_id = ibdev->ops.driver_id;
+
+	rc = uapi_merge_def(uapi, ibdev, uverbs_core_api, false);
+	if (rc)
+		goto err;
+	rc = uapi_merge_def(uapi, ibdev, ibdev->driver_def, true);
+	if (rc)
+		goto err;
+
+	uapi_finalize_disable(uapi);
+	rc = uapi_finalize(uapi);
+	if (rc)
+		goto err;
+
+	return uapi;
+err:
+	if (rc != -ENOMEM)
+		dev_err(&ibdev->dev,
+			"Setup of uverbs_api failed, kernel parsing tree description is not valid (%d)??\n",
+			rc);
+
+	uverbs_destroy_api(uapi);
+	return ERR_PTR(rc);
+}
+
+/*
+ * The pre version is done before destroying the HW objects, it only blocks
+ * off method access. All methods that require the ib_dev or the module data
+ * must test one of these assignments prior to continuing.
+ */
+void uverbs_disassociate_api_pre(struct ib_uverbs_device *uverbs_dev)
+{
+	struct uverbs_api *uapi = uverbs_dev->uapi;
+	struct radix_tree_iter iter;
+	void __rcu **slot;
+
+	rcu_assign_pointer(uverbs_dev->ib_dev, NULL);
+
+	radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
+		if (uapi_key_is_ioctl_method(iter.index)) {
+			struct uverbs_api_ioctl_method *method_elm =
+				rcu_dereference_protected(*slot, true);
+
+			if (method_elm->driver_method)
+				rcu_assign_pointer(method_elm->handler, NULL);
+		}
+	}
+
+	synchronize_srcu(&uverbs_dev->disassociate_srcu);
+}
+
+/*
+ * Called when a driver disassociates from the ib_uverbs_device. The
+ * assumption is that the driver module will unload after. Replace everything
+ * related to the driver with NULL as a safety measure.
+ */
+void uverbs_disassociate_api(struct uverbs_api *uapi)
+{
+	struct radix_tree_iter iter;
+	void __rcu **slot;
+
+	radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
+		if (uapi_key_is_object(iter.index)) {
+			struct uverbs_api_object *object_elm =
+				rcu_dereference_protected(*slot, true);
+
+			/*
+			 * Some type_attrs are in the driver module. We don't
+			 * bother to keep track of which since there should be
+			 * no use of this after disassociate.
+			 */
+			object_elm->type_attrs = NULL;
+		} else if (uapi_key_is_attr(iter.index)) {
+			struct uverbs_api_attr *elm =
+				rcu_dereference_protected(*slot, true);
+
+			if (elm->spec.type == UVERBS_ATTR_TYPE_ENUM_IN)
+				elm->spec.u2.enum_def.ids = NULL;
+		}
+	}
+}