@@ -31,4 +31,5 @@ ib_umad-y := user_mad.o
ib_ucm-y := ucm.o
ib_uverbs-y := uverbs_main.o uverbs_cmd.o uverbs_marshall.o \
- rdma_core.o uverbs_std_types.o uverbs_ioctl.o
+ rdma_core.o uverbs_std_types.o uverbs_ioctl.o \
+ uverbs_ioctl_merge.o
new file mode 100644
@@ -0,0 +1,665 @@
+/*
+ * Copyright (c) 2017, Mellanox Technologies inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <rdma/uverbs_ioctl.h>
+#include <rdma/rdma_user_ioctl.h>
+#include <linux/bitops.h>
+#include "uverbs.h"
+
+#define UVERBS_NUM_NS (UVERBS_ID_NS_MASK >> UVERBS_ID_NS_SHIFT)
+#define GET_NS_ID(idx) (((idx) & UVERBS_ID_NS_MASK) >> UVERBS_ID_NS_SHIFT)
+#define GET_ID(idx) ((idx) & ~UVERBS_ID_NS_MASK)
+
+#define _for_each_element(elem, tmpi, tmpj, hashes, num_buckets_offset, \
+ buckets_offset) \
+ for (tmpj = 0, \
+ elem = (*(const void ***)((hashes)[tmpi] + \
+ (buckets_offset)))[0]; \
+ tmpj < *(size_t *)((hashes)[tmpi] + (num_buckets_offset)); \
+ tmpj++) \
+ if ((elem = ((*(const void ***)(hashes[tmpi] + \
+ (buckets_offset)))[tmpj])))
+
+/*
+ * Iterate all elements of a few @hashes. The number of given hashes is
+ * indicated by @num_hashes. The offset of the number of buckets in the hash is
+ * represented by @num_buckets_offset, while the offset of the buckets array in
+ * the hash structure is represented by @buckets_offset. tmpi and tmpj are two
+ * short (or int) based indices that are given by the user. tmpi iterates over
+ * the different hashes. @elem points the current element in the hashes[tmpi]
+ * bucket we are looping on. To be honest, @hashes representation isn't exactly
+ * a hash, but more a collection of elements. These elements' ids are treated
+ * in a hash like manner, where the first upper bits are the bucket number.
+ * These elements are later mapped into a perfect-hash.
+ */
+#define for_each_element(elem, tmpi, tmpj, hashes, num_hashes, \
+ num_buckets_offset, buckets_offset) \
+ for (tmpi = 0; tmpi < (num_hashes); tmpi++) \
+ _for_each_element(elem, tmpi, tmpj, hashes, num_buckets_offset,\
+ buckets_offset)
+
+#define get_elements_iterators_entry_above(iters, num_elements, elements, \
+ num_objects_fld, objects_fld, bucket,\
+ min_id) \
+ get_elements_above_id((const void **)iters, num_elements, \
+ (const void **)(elements), \
+ offsetof(typeof(**elements), \
+ num_objects_fld), \
+ offsetof(typeof(**elements), objects_fld),\
+ offsetof(typeof(***(*elements)->objects_fld), id),\
+ bucket, min_id)
+
+#define get_objects_above_id(iters, num_trees, trees, bucket, min_id) \
+ get_elements_iterators_entry_above(iters, num_trees, trees, \
+ num_objects, objects, bucket, min_id)
+
+#define get_methods_above_id(method_iters, num_iters, iters, bucket, min_id)\
+ get_elements_iterators_entry_above(method_iters, num_iters, iters, \
+ num_methods, methods, bucket, min_id)
+
+#define get_attrs_above_id(attrs_iters, num_iters, iters, bucket, min_id)\
+ get_elements_iterators_entry_above(attrs_iters, num_iters, iters, \
+ num_attrs, attrs, bucket, min_id)
+
+/*
+ * get_elements_above_id get a few hashes represented by @elements and
+ * @num_elements. The hashes fields are described by @num_offset, @data_offset
+ * and @id_offset in the same way as required by for_each_element. The function
+ * returns an array of @iters, represents an array of elements in the hashes
+ * buckets, which their ids are the smallest ids in all hashes but are all
+ * larger than the id given by min_id. Elements are only added to the iters
+ * array if their id belongs to the bucket @bucket. The number of elements in
+ * the returned array is returned by the function. @min_id is also updated to
+ * reflect the new min_id of all elements in iters.
+ */
+static size_t get_elements_above_id(const void **iters,
+ unsigned int num_elements,
+ const void **elements,
+ size_t num_offset,
+ size_t data_offset,
+ size_t id_offset,
+ u16 bucket,
+ short *min_id)
+{
+ size_t num_iters = 0;
+ short min = SHRT_MAX;
+ const void *elem;
+ int i, j, last_stored = -1;
+
+ for_each_element(elem, i, j, elements, num_elements, num_offset,
+ data_offset) {
+ u16 id = *(u16 *)(elem + id_offset);
+
+ if (GET_NS_ID(id) != bucket)
+ continue;
+
+ if (GET_ID(id) < *min_id ||
+ (min != SHRT_MAX && GET_ID(id) > min))
+ continue;
+
+ /*
+ * We first iterate all hashes represented by @elements. When
+ * we do, we try to find an element @elem in the bucket @bucket
+ * which its id is min. Since we can't ensure the user sorted
+ * the elements in increasing order, we override this hash's
+ * minimal id element we found, if a new element with a smaller
+ * id was just found.
+ */
+ iters[last_stored == i ? num_iters - 1 : num_iters++] = elem;
+ last_stored = i;
+ min = GET_ID(id);
+ }
+
+ /*
+ * We only insert to our iters array an element, if its id is smaller
+ * than all previous ids. Therefore, the final iters array is sorted so
+ * that smaller ids are in the end of the array.
+ * Therefore, we need to clean the beginning of the array to make sure
+ * all ids of final elements are equal to min.
+ */
+ for (i = num_iters - 1; i >= 0 &&
+ GET_ID(*(u16 *)(iters[i] + id_offset)) == min; i--)
+ ;
+
+ num_iters -= i + 1;
+ memmove(iters, iters + i + 1, sizeof(*iters) * num_iters);
+
+ *min_id = min;
+ return num_iters;
+}
+
+#define find_max_element_entry_id(num_elements, elements, num_objects_fld, \
+ objects_fld, bucket) \
+ find_max_element_id(num_elements, (const void **)(elements), \
+ offsetof(typeof(**elements), num_objects_fld), \
+ offsetof(typeof(**elements), objects_fld), \
+ offsetof(typeof(***(*elements)->objects_fld), id),\
+ bucket)
+
+static short find_max_element_ns_id(unsigned int num_elements,
+ const void **elements,
+ size_t num_offset,
+ size_t data_offset,
+ size_t id_offset)
+{
+ short max_ns = SHRT_MIN;
+ const void *elem;
+ int i, j;
+
+ for_each_element(elem, i, j, elements, num_elements, num_offset,
+ data_offset) {
+ u16 id = *(u16 *)(elem + id_offset);
+
+ if (GET_NS_ID(id) > max_ns)
+ max_ns = GET_NS_ID(id);
+ }
+
+ return max_ns;
+}
+
+static short find_max_element_id(unsigned int num_elements,
+ const void **elements,
+ size_t num_offset,
+ size_t data_offset,
+ size_t id_offset,
+ u16 bucket)
+{
+ short max_id = SHRT_MIN;
+ const void *elem;
+ int i, j;
+
+ for_each_element(elem, i, j, elements, num_elements, num_offset,
+ data_offset) {
+ u16 id = *(u16 *)(elem + id_offset);
+
+ if (GET_NS_ID(id) == bucket &&
+ GET_ID(id) > max_id)
+ max_id = GET_ID(id);
+ }
+ return max_id;
+}
+
+#define find_max_element_entry_id(num_elements, elements, num_objects_fld, \
+ objects_fld, bucket) \
+ find_max_element_id(num_elements, (const void **)(elements), \
+ offsetof(typeof(**elements), num_objects_fld), \
+ offsetof(typeof(**elements), objects_fld), \
+ offsetof(typeof(***(*elements)->objects_fld), id),\
+ bucket)
+
+#define find_max_element_ns_entry_id(num_elements, elements, \
+ num_objects_fld, objects_fld) \
+ find_max_element_ns_id(num_elements, (const void **)(elements), \
+ offsetof(typeof(**elements), num_objects_fld),\
+ offsetof(typeof(**elements), objects_fld), \
+ offsetof(typeof(***(*elements)->objects_fld), id))
+
+/*
+ * find_max_xxxx_ns_id gets a few elements. Each element is described by an id
+ * which its upper bits represents a namespace. It finds the max namespace. This
+ * could be used in order to know how many buckets do we need to allocate. If no
+ * elements exist, SHRT_MIN is returned. Namespace represents here different
+ * buckets. The common example is "common bucket" and "driver bucket".
+ *
+ * find_max_xxxx_id gets a few elements and a bucket. Each element is described
+ * by an id which its upper bits represent a namespace. It returns the max id
+ * which is contained in the same namespace defined in @bucket. This could be
+ * used in order to know how many elements do we need to allocate in the bucket.
+ * If no elements exist, SHRT_MIN is returned.
+ */
+
+#define find_max_object_id(num_trees, trees, bucket) \
+ find_max_element_entry_id(num_trees, trees, num_objects,\
+ objects, bucket)
+#define find_max_object_ns_id(num_trees, trees) \
+ find_max_element_ns_entry_id(num_trees, trees, \
+ num_objects, objects)
+
+#define find_max_method_id(num_iters, iters, bucket) \
+ find_max_element_entry_id(num_iters, iters, num_methods,\
+ methods, bucket)
+#define find_max_method_ns_id(num_iters, iters) \
+ find_max_element_ns_entry_id(num_iters, iters, \
+ num_methods, methods)
+
+#define find_max_attr_id(num_iters, iters, bucket) \
+ find_max_element_entry_id(num_iters, iters, num_attrs, \
+ attrs, bucket)
+#define find_max_attr_ns_id(num_iters, iters) \
+ find_max_element_ns_entry_id(num_iters, iters, \
+ num_attrs, attrs)
+
+static void free_method(struct uverbs_method_spec *method)
+{
+ unsigned int i;
+
+ if (!method)
+ return;
+
+ for (i = 0; i < method->num_buckets; i++)
+ kfree(method->attr_buckets[i]);
+
+ kfree(method);
+}
+
+#define IS_ATTR_OBJECT(attr) ((attr)->type == UVERBS_ATTR_TYPE_IDR || \
+ (attr)->type == UVERBS_ATTR_TYPE_FD)
+
+/*
+ * This function gets array of size @num_method_defs which contains pointers to
+ * method definitions @method_defs. The function allocates an
+ * uverbs_method_spec structure and initializes its number of buckets and the
+ * elements in buckets to the correct attributes. While doing that, it
+ * validates that there aren't conflicts between attributes of different
+ * method_defs.
+ */
+static struct uverbs_method_spec *build_method_with_attrs(const struct uverbs_method_def **method_defs,
+ size_t num_method_defs)
+{
+ int bucket_idx;
+ int max_attr_buckets = 0;
+ size_t num_attr_buckets = 0;
+ int res = 0;
+ struct uverbs_method_spec *method = NULL;
+ const struct uverbs_attr_def **attr_defs;
+ unsigned int num_of_singularities = 0;
+
+ max_attr_buckets = find_max_attr_ns_id(num_method_defs, method_defs);
+ if (max_attr_buckets >= 0)
+ num_attr_buckets = max_attr_buckets + 1;
+
+ method = kzalloc(sizeof(*method) +
+ num_attr_buckets * sizeof(*method->attr_buckets),
+ GFP_KERNEL);
+ if (!method)
+ return ERR_PTR(-ENOMEM);
+
+ method->num_buckets = num_attr_buckets;
+ attr_defs = kcalloc(num_method_defs, sizeof(*attr_defs), GFP_KERNEL);
+ if (!attr_defs) {
+ res = -ENOMEM;
+ goto free_method;
+ }
+ for (bucket_idx = 0; bucket_idx < method->num_buckets; bucket_idx++) {
+ short min_id = SHRT_MIN;
+ int attr_max_bucket = 0;
+ struct uverbs_attr_spec_hash *hash = NULL;
+
+ attr_max_bucket = find_max_attr_id(num_method_defs, method_defs,
+ bucket_idx);
+ if (attr_max_bucket < 0)
+ continue;
+
+ hash = kzalloc(sizeof(*hash) +
+ ALIGN(sizeof(*hash->attrs) * (attr_max_bucket + 1),
+ sizeof(long)) +
+ BITS_TO_LONGS(attr_max_bucket) * sizeof(long),
+ GFP_KERNEL);
+ if (!hash) {
+ res = -ENOMEM;
+ goto free;
+ }
+ hash->num_attrs = attr_max_bucket + 1;
+ method->num_child_attrs += hash->num_attrs;
+ hash->mandatory_attrs_bitmask = (void *)(hash + 1) +
+ ALIGN(sizeof(*hash->attrs) *
+ (attr_max_bucket + 1),
+ sizeof(long));
+
+ method->attr_buckets[bucket_idx] = hash;
+
+ do {
+ size_t num_attr_defs;
+ struct uverbs_attr_spec *attr;
+ bool attr_obj_with_special_access;
+
+ num_attr_defs =
+ get_attrs_above_id(attr_defs,
+ num_method_defs,
+ method_defs,
+ bucket_idx,
+ &min_id);
+ /* Last attr in bucket */
+ if (!num_attr_defs)
+ break;
+
+ if (num_attr_defs > 1) {
+ /*
+ * We don't allow two attribute definitions for
+ * the same attribute. This is usually a
+ * programmer error. If required, it's better to
+ * just add a new attribute to capture the new
+ * semantics.
+ */
+ res = -EEXIST;
+ goto free;
+ }
+
+ attr = &hash->attrs[min_id];
+ memcpy(attr, &attr_defs[0]->attr, sizeof(*attr));
+
+ attr_obj_with_special_access = IS_ATTR_OBJECT(attr) &&
+ (attr->obj.access == UVERBS_ACCESS_NEW ||
+ attr->obj.access == UVERBS_ACCESS_DESTROY);
+ num_of_singularities += !!attr_obj_with_special_access;
+ if (WARN(num_of_singularities > 1,
+ "ib_uverbs: Method contains more than one object attr (%d) with new/destroy access\n",
+ min_id) ||
+ WARN(attr_obj_with_special_access &&
+ !(attr->flags & UVERBS_ATTR_SPEC_F_MANDATORY),
+ "ib_uverbs: Tried to merge attr (%d) but it's an object with new/destroy aceess but isn't mandatory\n",
+ min_id) ||
+ WARN(IS_ATTR_OBJECT(attr) &&
+ attr->flags & UVERBS_ATTR_SPEC_F_MIN_SZ,
+ "ib_uverbs: Tried to merge attr (%d) but it's an object with min_sz flag\n",
+ min_id)) {
+ res = -EINVAL;
+ goto free;
+ }
+
+ if (attr->flags & UVERBS_ATTR_SPEC_F_MANDATORY)
+ set_bit(min_id, hash->mandatory_attrs_bitmask);
+ min_id++;
+
+ } while (1);
+ }
+ kfree(attr_defs);
+ return method;
+
+free:
+ kfree(attr_defs);
+free_method:
+ free_method(method);
+ return ERR_PTR(res);
+}
+
+static void free_object(struct uverbs_object_spec *object)
+{
+ unsigned int i, j;
+
+ if (!object)
+ return;
+
+ for (i = 0; i < object->num_buckets; i++) {
+ struct uverbs_method_spec_hash *method_buckets =
+ object->method_buckets[i];
+
+ if (!method_buckets)
+ continue;
+
+ for (j = 0; j < method_buckets->num_methods; j++)
+ free_method(method_buckets->methods[j]);
+
+ kfree(method_buckets);
+ }
+
+ kfree(object);
+}
+
+/*
+ * This function gets array of size @num_object_defs which contains pointers to
+ * object definitions @object_defs. The function allocated an
+ * uverbs_object_spec structure and initialize its number of buckets and the
+ * elements in buckets to the correct methods. While doing that, it
+ * sorts out the correct relationship between conflicts in the same method.
+ */
+static struct uverbs_object_spec *build_object_with_methods(const struct uverbs_object_def **object_defs,
+ size_t num_object_defs)
+{
+ u16 bucket_idx;
+ int max_method_buckets = 0;
+ u16 num_method_buckets = 0;
+ int res = 0;
+ struct uverbs_object_spec *object = NULL;
+ const struct uverbs_method_def **method_defs;
+
+ max_method_buckets = find_max_method_ns_id(num_object_defs, object_defs);
+ if (max_method_buckets >= 0)
+ num_method_buckets = max_method_buckets + 1;
+
+ object = kzalloc(sizeof(*object) +
+ num_method_buckets *
+ sizeof(*object->method_buckets), GFP_KERNEL);
+ if (!object)
+ return ERR_PTR(-ENOMEM);
+
+ object->num_buckets = num_method_buckets;
+ method_defs = kcalloc(num_object_defs, sizeof(*method_defs), GFP_KERNEL);
+ if (!method_defs) {
+ res = -ENOMEM;
+ goto free_object;
+ }
+
+ for (bucket_idx = 0; bucket_idx < object->num_buckets; bucket_idx++) {
+ short min_id = SHRT_MIN;
+ int methods_max_bucket = 0;
+ struct uverbs_method_spec_hash *hash = NULL;
+
+ methods_max_bucket = find_max_method_id(num_object_defs, object_defs,
+ bucket_idx);
+ if (methods_max_bucket < 0)
+ continue;
+
+ hash = kzalloc(sizeof(*hash) +
+ sizeof(*hash->methods) * (methods_max_bucket + 1),
+ GFP_KERNEL);
+ if (!hash) {
+ res = -ENOMEM;
+ goto free;
+ }
+
+ hash->num_methods = methods_max_bucket + 1;
+ object->method_buckets[bucket_idx] = hash;
+
+ do {
+ size_t num_method_defs;
+ struct uverbs_method_spec *method;
+ int i;
+
+ num_method_defs =
+ get_methods_above_id(method_defs,
+ num_object_defs,
+ object_defs,
+ bucket_idx,
+ &min_id);
+ /* Last method in bucket */
+ if (!num_method_defs)
+ break;
+
+ method = build_method_with_attrs(method_defs,
+ num_method_defs);
+ if (IS_ERR(method)) {
+ res = PTR_ERR(method);
+ goto free;
+ }
+
+ /*
+ * The last tree which is given as an argument to the
+ * merge overrides previous method handler.
+ * Therefore, we iterate backwards and search for the
+ * first handler which != NULL. This also defines the
+ * set of flags used for this handler.
+ */
+ for (i = num_object_defs - 1;
+ i >= 0 && !method_defs[i]->handler; i--)
+ ;
+ hash->methods[min_id++] = method;
+ /* NULL handler isn't allowed */
+ if (WARN(i < 0,
+ "ib_uverbs: tried to merge function id %d, but all handlers are NULL\n",
+ min_id)) {
+ res = -EINVAL;
+ goto free;
+ }
+ method->handler = method_defs[i]->handler;
+ method->flags = method_defs[i]->flags;
+
+ } while (1);
+ }
+ kfree(method_defs);
+ return object;
+
+free:
+ kfree(method_defs);
+free_object:
+ free_object(object);
+ return ERR_PTR(res);
+}
+
+void uverbs_free_spec_tree(struct uverbs_root_spec *root)
+{
+ unsigned int i, j;
+
+ if (!root)
+ return;
+
+ for (i = 0; i < root->num_buckets; i++) {
+ struct uverbs_object_spec_hash *object_hash =
+ root->object_buckets[i];
+
+ if (!object_hash)
+ continue;
+
+ for (j = 0; j < object_hash->num_objects; j++)
+ free_object(object_hash->objects[j]);
+
+ kfree(object_hash);
+ }
+
+ kfree(root);
+}
+EXPORT_SYMBOL(uverbs_free_spec_tree);
+
+struct uverbs_root_spec *uverbs_alloc_spec_tree(unsigned int num_trees,
+ const struct uverbs_object_tree_def **trees)
+{
+ u16 bucket_idx;
+ short max_object_buckets = 0;
+ size_t num_objects_buckets = 0;
+ struct uverbs_root_spec *root_spec = NULL;
+ const struct uverbs_object_def **object_defs;
+ int i;
+ int res = 0;
+
+ max_object_buckets = find_max_object_ns_id(num_trees, trees);
+ /*
+ * Devices which don't want to support ib_uverbs, should just allocate
+ * an empty parsing tree. Every user-space command won't hit any valid
+ * entry in the parsing tree and thus will fail.
+ */
+ if (max_object_buckets >= 0)
+ num_objects_buckets = max_object_buckets + 1;
+
+ root_spec = kzalloc(sizeof(*root_spec) +
+ num_objects_buckets * sizeof(*root_spec->object_buckets),
+ GFP_KERNEL);
+ if (!root_spec)
+ return ERR_PTR(-ENOMEM);
+ root_spec->num_buckets = num_objects_buckets;
+
+ object_defs = kcalloc(num_trees, sizeof(*object_defs),
+ GFP_KERNEL);
+ if (!object_defs) {
+ res = -ENOMEM;
+ goto free_root;
+ }
+
+ for (bucket_idx = 0; bucket_idx < root_spec->num_buckets; bucket_idx++) {
+ short min_id = SHRT_MIN;
+ short objects_max_bucket;
+ struct uverbs_object_spec_hash *hash = NULL;
+
+ objects_max_bucket = find_max_object_id(num_trees, trees,
+ bucket_idx);
+ if (objects_max_bucket < 0)
+ continue;
+
+ hash = kzalloc(sizeof(*hash) +
+ sizeof(*hash->objects) * (objects_max_bucket + 1),
+ GFP_KERNEL);
+ if (!hash) {
+ res = -ENOMEM;
+ goto free;
+ }
+ hash->num_objects = objects_max_bucket + 1;
+ root_spec->object_buckets[bucket_idx] = hash;
+
+ do {
+ size_t num_object_defs;
+ struct uverbs_object_spec *object;
+
+ num_object_defs = get_objects_above_id(object_defs,
+ num_trees,
+ trees,
+ bucket_idx,
+ &min_id);
+ /* Last object in bucket */
+ if (!num_object_defs)
+ break;
+
+ object = build_object_with_methods(object_defs,
+ num_object_defs);
+ if (IS_ERR(object)) {
+ res = PTR_ERR(object);
+ goto free;
+ }
+
+ /*
+ * The last tree which is given as an argument to the
+ * merge overrides previous object's type_attrs.
+ * Therefore, we iterate backwards and search for the
+ * first type_attrs which != NULL.
+ */
+ for (i = num_object_defs - 1;
+ i >= 0 && !object_defs[i]->type_attrs; i--)
+ ;
+ /*
+ * NULL is a valid type_attrs. It means an object we
+ * can't instantiate (like DEVICE).
+ */
+ object->type_attrs = i < 0 ? NULL :
+ object_defs[i]->type_attrs;
+
+ hash->objects[min_id++] = object;
+ } while (1);
+ }
+
+ kfree(object_defs);
+ return root_spec;
+
+free:
+ kfree(object_defs);
+free_root:
+ uverbs_free_spec_tree(root_spec);
+ return ERR_PTR(res);
+}
+EXPORT_SYMBOL(uverbs_alloc_spec_tree);
@@ -235,5 +235,43 @@ static inline bool uverbs_attr_is_valid_in_hash(const struct uverbs_attr_bundle_
return test_bit(idx, attrs_hash->valid_bitmap);
}
-#endif
+/* =================================================
+ * Definitions -> Specs infrastructure
+ * =================================================
+ */
+
+/*
+ * uverbs_alloc_spec_tree - Merges different common and driver specific feature
+ * into one parsing tree that every uverbs command will be parsed upon.
+ *
+ * @num_trees: Number of trees in the array @trees.
+ * @trees: Array of pointers to tree root definitions to merge. Each such tree
+ * possibly contains objects, methods and attributes definitions.
+ *
+ * Returns:
+ * uverbs_root_spec *: The root of the merged parsing tree.
+ * On error, we return an error code. Error is checked via IS_ERR.
+ *
+ * The following merges could take place:
+ * a. Two trees representing the same method with different handler
+ * -> We take the handler of the tree that its handler != NULL
+ * and its index in the trees array is greater. The incentive for that
+ * is that developers are expected to first merge common trees and then
+ * merge trees that gives specialized the behaviour.
+ * b. Two trees representing the same object with different
+ * type_attrs (struct uverbs_obj_type):
+ * -> We take the type_attrs of the tree that its type_attr != NULL
+ * and its index in the trees array is greater. This could be used
+ * in order to override the free function, allocation size, etc.
+ * c. Two trees representing the same method attribute (same id but possibly
+ * different attributes):
+ * -> ERROR (-ENOENT), we believe that's not the programmer's intent.
+ *
+ * An object without any methods is considered invalid and will abort the
+ * function with -ENOENT error.
+ */
+struct uverbs_root_spec *uverbs_alloc_spec_tree(unsigned int num_trees,
+ const struct uverbs_object_tree_def **trees);
+void uverbs_free_spec_tree(struct uverbs_root_spec *root);
+#endif