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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
 /* Copyright (c) 2018 Mellanox Technologies. All rights reserved */
 
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/rhashtable.h>
 #include <linux/idr.h>
 #include <linux/list.h>
 #include <linux/sort.h>
 #include <linux/objagg.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/objagg.h>
 
 struct objagg_hints {
     struct rhashtable node_ht;
     struct rhashtable_params ht_params;
     struct list_head node_list;
     unsigned int node_count;
     unsigned int root_count;
     unsigned int refcount;
     const struct objagg_ops *ops;
 };
 
 struct objagg_hints_node {
     struct rhash_head ht_node; /* member of objagg_hints->node_ht */
     struct list_head list; /* member of objagg_hints->node_list */
     struct objagg_hints_node *parent;
     unsigned int root_id;
     struct objagg_obj_stats_info stats_info;
     unsigned long obj[];
 };
 
 static struct objagg_hints_node *
 objagg_hints_lookup(struct objagg_hints *objagg_hints, void *obj)
 {
     if (!objagg_hints)
         return NULL;
     return rhashtable_lookup_fast(&objagg_hints->node_ht, obj,
                       objagg_hints->ht_params);
 }
 
 struct objagg {
     const struct objagg_ops *ops;
     void *priv;
     struct rhashtable obj_ht;
     struct rhashtable_params ht_params;
     struct list_head obj_list;
     unsigned int obj_count;
     struct ida root_ida;
     struct objagg_hints *hints;
 };
 
 struct objagg_obj {
     struct rhash_head ht_node; /* member of objagg->obj_ht */
     struct list_head list; /* member of objagg->obj_list */
     struct objagg_obj *parent; /* if the object is nested, this
                     * holds pointer to parent, otherwise NULL
                     */
     union {
         void *delta_priv; /* user delta private */
         void *root_priv; /* user root private */
     };
     unsigned int root_id;
     unsigned int refcount; /* counts number of users of this object
                 * including nested objects
                 */
     struct objagg_obj_stats stats;
     unsigned long obj[];
 };
 
 static unsigned int objagg_obj_ref_inc(struct objagg_obj *objagg_obj)
 {
     return ++objagg_obj->refcount;
 }
 
 static unsigned int objagg_obj_ref_dec(struct objagg_obj *objagg_obj)
 {
     return --objagg_obj->refcount;
 }
 
 static void objagg_obj_stats_inc(struct objagg_obj *objagg_obj)
 {
     objagg_obj->stats.user_count++;
     objagg_obj->stats.delta_user_count++;
     if (objagg_obj->parent)
         objagg_obj->parent->stats.delta_user_count++;
 }
 
 static void objagg_obj_stats_dec(struct objagg_obj *objagg_obj)
 {
     objagg_obj->stats.user_count--;
     objagg_obj->stats.delta_user_count--;
     if (objagg_obj->parent)
         objagg_obj->parent->stats.delta_user_count--;
 }
 
 static bool objagg_obj_is_root(const struct objagg_obj *objagg_obj)
 {
     /* Nesting is not supported, so we can use ->parent
      * to figure out if the object is root.
      */
     return !objagg_obj->parent;
 }
 
 /**
  * objagg_obj_root_priv - obtains root private for an object
  * @objagg_obj: objagg object instance
  *
  * Note: all locking must be provided by the caller.
  *
  * Either the object is root itself when the private is returned
  * directly, or the parent is root and its private is returned
  * instead.
  *
  * Returns a user private root pointer.
  */
 const void *objagg_obj_root_priv(const struct objagg_obj *objagg_obj)
 {
     if (objagg_obj_is_root(objagg_obj))
         return objagg_obj->root_priv;
     WARN_ON(!objagg_obj_is_root(objagg_obj->parent));
     return objagg_obj->parent->root_priv;
 }
 EXPORT_SYMBOL(objagg_obj_root_priv);
 
 /**
  * objagg_obj_delta_priv - obtains delta private for an object
  * @objagg_obj: objagg object instance
  *
  * Note: all locking must be provided by the caller.
  *
  * Returns user private delta pointer or NULL in case the passed
  * object is root.
  */
 const void *objagg_obj_delta_priv(const struct objagg_obj *objagg_obj)
 {
     if (objagg_obj_is_root(objagg_obj))
         return NULL;
     return objagg_obj->delta_priv;
 }
 EXPORT_SYMBOL(objagg_obj_delta_priv);
 
 /**
  * objagg_obj_raw - obtains object user private pointer
  * @objagg_obj: objagg object instance
  *
  * Note: all locking must be provided by the caller.
  *
  * Returns user private pointer as was passed to objagg_obj_get() by "obj" arg.
  */
 const void *objagg_obj_raw(const struct objagg_obj *objagg_obj)
 {
     return objagg_obj->obj;
 }
 EXPORT_SYMBOL(objagg_obj_raw);
 
 static struct objagg_obj *objagg_obj_lookup(struct objagg *objagg, void *obj)
 {
     return rhashtable_lookup_fast(&objagg->obj_ht, obj, objagg->ht_params);
 }
 
 static int objagg_obj_parent_assign(struct objagg *objagg,
                     struct objagg_obj *objagg_obj,
                     struct objagg_obj *parent,
                     bool take_parent_ref)
 {
     void *delta_priv;
 
     delta_priv = objagg->ops->delta_create(objagg->priv, parent->obj,
                            objagg_obj->obj);
     if (IS_ERR(delta_priv))
         return PTR_ERR(delta_priv);
 
     /* User returned a delta private, that means that
      * our object can be aggregated into the parent.
      */
     objagg_obj->parent = parent;
     objagg_obj->delta_priv = delta_priv;
     if (take_parent_ref)
         objagg_obj_ref_inc(objagg_obj->parent);
     trace_objagg_obj_parent_assign(objagg, objagg_obj,
                        parent,
                        parent->refcount);
     return 0;
 }
 
 static int objagg_obj_parent_lookup_assign(struct objagg *objagg,
                        struct objagg_obj *objagg_obj)
 {
     struct objagg_obj *objagg_obj_cur;
     int err;
 
     list_for_each_entry(objagg_obj_cur, &objagg->obj_list, list) {
         /* Nesting is not supported. In case the object
          * is not root, it cannot be assigned as parent.
          */
         if (!objagg_obj_is_root(objagg_obj_cur))
             continue;
         err = objagg_obj_parent_assign(objagg, objagg_obj,
                            objagg_obj_cur, true);
         if (!err)
             return 0;
     }
     return -ENOENT;
 }
 
 static void __objagg_obj_put(struct objagg *objagg,
                  struct objagg_obj *objagg_obj);
 
 static void objagg_obj_parent_unassign(struct objagg *objagg,
                        struct objagg_obj *objagg_obj)
 {
     trace_objagg_obj_parent_unassign(objagg, objagg_obj,
                      objagg_obj->parent,
                      objagg_obj->parent->refcount);
     objagg->ops->delta_destroy(objagg->priv, objagg_obj->delta_priv);
     __objagg_obj_put(objagg, objagg_obj->parent);
 }
 
 static int objagg_obj_root_id_alloc(struct objagg *objagg,
                     struct objagg_obj *objagg_obj,
                     struct objagg_hints_node *hnode)
 {
     unsigned int min, max;
     int root_id;
 
     /* In case there are no hints available, the root id is invalid. */
     if (!objagg->hints) {
         objagg_obj->root_id = OBJAGG_OBJ_ROOT_ID_INVALID;
         return 0;
     }
 
     if (hnode) {
         min = hnode->root_id;
         max = hnode->root_id;
     } else {
         /* For objects with no hint, start after the last
          * hinted root_id.
          */
         min = objagg->hints->root_count;
         max = ~0;
     }
 
     root_id = ida_alloc_range(&objagg->root_ida, min, max, GFP_KERNEL);
 
     if (root_id < 0)
         return root_id;
     objagg_obj->root_id = root_id;
     return 0;
 }
 
 static void objagg_obj_root_id_free(struct objagg *objagg,
                     struct objagg_obj *objagg_obj)
 {
     if (!objagg->hints)
         return;
     ida_free(&objagg->root_ida, objagg_obj->root_id);
 }
 
 static int objagg_obj_root_create(struct objagg *objagg,
                   struct objagg_obj *objagg_obj,
                   struct objagg_hints_node *hnode)
 {
     int err;
 
     err = objagg_obj_root_id_alloc(objagg, objagg_obj, hnode);
     if (err)
         return err;
     objagg_obj->root_priv = objagg->ops->root_create(objagg->priv,
                              objagg_obj->obj,
                              objagg_obj->root_id);
     if (IS_ERR(objagg_obj->root_priv)) {
         err = PTR_ERR(objagg_obj->root_priv);
         goto err_root_create;
     }
     trace_objagg_obj_root_create(objagg, objagg_obj);
     return 0;
 
 err_root_create:
     objagg_obj_root_id_free(objagg, objagg_obj);
     return err;
 }
 
 static void objagg_obj_root_destroy(struct objagg *objagg,
                     struct objagg_obj *objagg_obj)
 {
     trace_objagg_obj_root_destroy(objagg, objagg_obj);
     objagg->ops->root_destroy(objagg->priv, objagg_obj->root_priv);
     objagg_obj_root_id_free(objagg, objagg_obj);
 }
 
 static struct objagg_obj *__objagg_obj_get(struct objagg *objagg, void *obj);
 
 static int objagg_obj_init_with_hints(struct objagg *objagg,
                       struct objagg_obj *objagg_obj,
                       bool *hint_found)
 {
     struct objagg_hints_node *hnode;
     struct objagg_obj *parent;
     int err;
 
     hnode = objagg_hints_lookup(objagg->hints, objagg_obj->obj);
     if (!hnode) {
         *hint_found = false;
         return 0;
     }
     *hint_found = true;
 
     if (!hnode->parent)
         return objagg_obj_root_create(objagg, objagg_obj, hnode);
 
     parent = __objagg_obj_get(objagg, hnode->parent->obj);
     if (IS_ERR(parent))
         return PTR_ERR(parent);
 
     err = objagg_obj_parent_assign(objagg, objagg_obj, parent, false);
     if (err) {
         *hint_found = false;
         err = 0;
         goto err_parent_assign;
     }
 
     return 0;
 
 err_parent_assign:
     objagg_obj_put(objagg, parent);
     return err;
 }
 
 static int objagg_obj_init(struct objagg *objagg,
                struct objagg_obj *objagg_obj)
 {
     bool hint_found;
     int err;
 
     /* First, try to use hints if they are available and
      * if they provide result.
      */
     err = objagg_obj_init_with_hints(objagg, objagg_obj, &hint_found);
     if (err)
         return err;
 
     if (hint_found)
         return 0;
 
     /* Try to find if the object can be aggregated under an existing one. */
     err = objagg_obj_parent_lookup_assign(objagg, objagg_obj);
     if (!err)
         return 0;
     /* If aggregation is not possible, make the object a root. */
     return objagg_obj_root_create(objagg, objagg_obj, NULL);
 }
 
 static void objagg_obj_fini(struct objagg *objagg,
                 struct objagg_obj *objagg_obj)
 {
     if (!objagg_obj_is_root(objagg_obj))
         objagg_obj_parent_unassign(objagg, objagg_obj);
     else
         objagg_obj_root_destroy(objagg, objagg_obj);
 }
 
 static struct objagg_obj *objagg_obj_create(struct objagg *objagg, void *obj)
 {
     struct objagg_obj *objagg_obj;
     int err;
 
     objagg_obj = kzalloc(sizeof(*objagg_obj) + objagg->ops->obj_size,
                  GFP_KERNEL);
     if (!objagg_obj)
         return ERR_PTR(-ENOMEM);
     objagg_obj_ref_inc(objagg_obj);
     memcpy(objagg_obj->obj, obj, objagg->ops->obj_size);
 
     err = objagg_obj_init(objagg, objagg_obj);
     if (err)
         goto err_obj_init;
 
     err = rhashtable_insert_fast(&objagg->obj_ht, &objagg_obj->ht_node,
                      objagg->ht_params);
     if (err)
         goto err_ht_insert;
     list_add(&objagg_obj->list, &objagg->obj_list);
     objagg->obj_count++;
     trace_objagg_obj_create(objagg, objagg_obj);
 
     return objagg_obj;
 
 err_ht_insert:
     objagg_obj_fini(objagg, objagg_obj);
 err_obj_init:
     kfree(objagg_obj);
     return ERR_PTR(err);
 }
 
 static struct objagg_obj *__objagg_obj_get(struct objagg *objagg, void *obj)
 {
     struct objagg_obj *objagg_obj;
 
     /* First, try to find the object exactly as user passed it,
      * perhaps it is already in use.
      */
     objagg_obj = objagg_obj_lookup(objagg, obj);
     if (objagg_obj) {
         objagg_obj_ref_inc(objagg_obj);
         return objagg_obj;
     }
 
     return objagg_obj_create(objagg, obj);
 }
 
 /**
  * objagg_obj_get - gets an object within objagg instance
  * @objagg: objagg instance
  * @obj:    user-specific private object pointer
  *
  * Note: all locking must be provided by the caller.
  *
  * Size of the "obj" memory is specified in "objagg->ops".
  *
  * There are 3 main options this function wraps:
  * 1) The object according to "obj" already exist. In that case
  *    the reference counter is incrementes and the object is returned.
  * 2) The object does not exist, but it can be aggregated within
  *    another object. In that case, user ops->delta_create() is called
  *    to obtain delta data and a new object is created with returned
  *    user-delta private pointer.
  * 3) The object does not exist and cannot be aggregated into
  *    any of the existing objects. In that case, user ops->root_create()
  *    is called to create the root and a new object is created with
  *    returned user-root private pointer.
  *
  * Returns a pointer to objagg object instance in case of success,
  * otherwise it returns pointer error using ERR_PTR macro.
  */
 struct objagg_obj *objagg_obj_get(struct objagg *objagg, void *obj)
 {
     struct objagg_obj *objagg_obj;
 
     objagg_obj = __objagg_obj_get(objagg, obj);
     if (IS_ERR(objagg_obj))
         return objagg_obj;
     objagg_obj_stats_inc(objagg_obj);
     trace_objagg_obj_get(objagg, objagg_obj, objagg_obj->refcount);
     return objagg_obj;
 }
 EXPORT_SYMBOL(objagg_obj_get);
 
 static void objagg_obj_destroy(struct objagg *objagg,
                    struct objagg_obj *objagg_obj)
 {
     trace_objagg_obj_destroy(objagg, objagg_obj);
     --objagg->obj_count;
     list_del(&objagg_obj->list);
     rhashtable_remove_fast(&objagg->obj_ht, &objagg_obj->ht_node,
                    objagg->ht_params);
     objagg_obj_fini(objagg, objagg_obj);
     kfree(objagg_obj);
 }
 
 static void __objagg_obj_put(struct objagg *objagg,
                  struct objagg_obj *objagg_obj)
 {
     if (!objagg_obj_ref_dec(objagg_obj))
         objagg_obj_destroy(objagg, objagg_obj);
 }
 
 /**
  * objagg_obj_put - puts an object within objagg instance
  * @objagg: objagg instance
  * @objagg_obj: objagg object instance
  *
  * Note: all locking must be provided by the caller.
  *
  * Symmetric to objagg_obj_get().
  */
 void objagg_obj_put(struct objagg *objagg, struct objagg_obj *objagg_obj)
 {
     trace_objagg_obj_put(objagg, objagg_obj, objagg_obj->refcount);
     objagg_obj_stats_dec(objagg_obj);
     __objagg_obj_put(objagg, objagg_obj);
 }
 EXPORT_SYMBOL(objagg_obj_put);
 
 /**
  * objagg_create - creates a new objagg instance
  * @ops:        user-specific callbacks
  * @objagg_hints:   hints, can be NULL
  * @priv:       pointer to a private data passed to the ops
  *
  * Note: all locking must be provided by the caller.
  *
  * The purpose of the library is to provide an infrastructure to
  * aggregate user-specified objects. Library does not care about the type
  * of the object. User fills-up ops which take care of the specific
  * user object manipulation.
  *
  * As a very stupid example, consider integer numbers. For example
  * number 8 as a root object. That can aggregate number 9 with delta 1,
  * number 10 with delta 2, etc. This example is implemented as
  * a part of a testing module in test_objagg.c file.
  *
  * Each objagg instance contains multiple trees. Each tree node is
  * represented by "an object". In the current implementation there can be
  * only roots and leafs nodes. Leaf nodes are called deltas.
  * But in general, this can be easily extended for intermediate nodes.
  * In that extension, a delta would be associated with all non-root
  * nodes.
  *
  * Returns a pointer to newly created objagg instance in case of success,
  * otherwise it returns pointer error using ERR_PTR macro.
  */
 struct objagg *objagg_create(const struct objagg_ops *ops,
                  struct objagg_hints *objagg_hints, void *priv)
 {
     struct objagg *objagg;
     int err;
 
     if (WARN_ON(!ops || !ops->root_create || !ops->root_destroy ||
             !ops->delta_check || !ops->delta_create ||
             !ops->delta_destroy))
         return ERR_PTR(-EINVAL);
 
     objagg = kzalloc(sizeof(*objagg), GFP_KERNEL);
     if (!objagg)
         return ERR_PTR(-ENOMEM);
     objagg->ops = ops;
     if (objagg_hints) {
         objagg->hints = objagg_hints;
         objagg_hints->refcount++;
     }
     objagg->priv = priv;
     INIT_LIST_HEAD(&objagg->obj_list);
 
     objagg->ht_params.key_len = ops->obj_size;
     objagg->ht_params.key_offset = offsetof(struct objagg_obj, obj);
     objagg->ht_params.head_offset = offsetof(struct objagg_obj, ht_node);
 
     err = rhashtable_init(&objagg->obj_ht, &objagg->ht_params);
     if (err)
         goto err_rhashtable_init;
 
     ida_init(&objagg->root_ida);
 
     trace_objagg_create(objagg);
     return objagg;
 
 err_rhashtable_init:
     kfree(objagg);
     return ERR_PTR(err);
 }
 EXPORT_SYMBOL(objagg_create);
 
 /**
  * objagg_destroy - destroys a new objagg instance
  * @objagg: objagg instance
  *
  * Note: all locking must be provided by the caller.
  */
 void objagg_destroy(struct objagg *objagg)
 {
     trace_objagg_destroy(objagg);
     ida_destroy(&objagg->root_ida);
     WARN_ON(!list_empty(&objagg->obj_list));
     rhashtable_destroy(&objagg->obj_ht);
     if (objagg->hints)
         objagg_hints_put(objagg->hints);
     kfree(objagg);
 }
 EXPORT_SYMBOL(objagg_destroy);
 
 static int objagg_stats_info_sort_cmp_func(const void *a, const void *b)
 {
     const struct objagg_obj_stats_info *stats_info1 = a;
     const struct objagg_obj_stats_info *stats_info2 = b;
 
     if (stats_info1->is_root != stats_info2->is_root)
         return stats_info2->is_root - stats_info1->is_root;
     if (stats_info1->stats.delta_user_count !=
         stats_info2->stats.delta_user_count)
         return stats_info2->stats.delta_user_count -
                stats_info1->stats.delta_user_count;
     return stats_info2->stats.user_count - stats_info1->stats.user_count;
 }
 
 /**
  * objagg_stats_get - obtains stats of the objagg instance
  * @objagg: objagg instance
  *
  * Note: all locking must be provided by the caller.
  *
  * The returned structure contains statistics of all object
  * currently in use, ordered by following rules:
  * 1) Root objects are always on lower indexes than the rest.
  * 2) Objects with higher delta user count are always on lower
  *    indexes.
  * 3) In case more objects have the same delta user count,
  *    the objects are ordered by user count.
  *
  * Returns a pointer to stats instance in case of success,
  * otherwise it returns pointer error using ERR_PTR macro.
  */
 const struct objagg_stats *objagg_stats_get(struct objagg *objagg)
 {
     struct objagg_stats *objagg_stats;
     struct objagg_obj *objagg_obj;
     int i;
 
     objagg_stats = kzalloc(struct_size(objagg_stats, stats_info,
                        objagg->obj_count), GFP_KERNEL);
     if (!objagg_stats)
         return ERR_PTR(-ENOMEM);
 
     i = 0;
     list_for_each_entry(objagg_obj, &objagg->obj_list, list) {
         memcpy(&objagg_stats->stats_info[i].stats, &objagg_obj->stats,
                sizeof(objagg_stats->stats_info[0].stats));
         objagg_stats->stats_info[i].objagg_obj = objagg_obj;
         objagg_stats->stats_info[i].is_root =
                     objagg_obj_is_root(objagg_obj);
         if (objagg_stats->stats_info[i].is_root)
             objagg_stats->root_count++;
         i++;
     }
     objagg_stats->stats_info_count = i;
 
     sort(objagg_stats->stats_info, objagg_stats->stats_info_count,
          sizeof(struct objagg_obj_stats_info),
          objagg_stats_info_sort_cmp_func, NULL);
 
     return objagg_stats;
 }
 EXPORT_SYMBOL(objagg_stats_get);
 
 /**
  * objagg_stats_put - puts stats of the objagg instance
  * @objagg_stats:   objagg instance stats
  *
  * Note: all locking must be provided by the caller.
  */
 void objagg_stats_put(const struct objagg_stats *objagg_stats)
 {
     kfree(objagg_stats);
 }
 EXPORT_SYMBOL(objagg_stats_put);
 
 static struct objagg_hints_node *
 objagg_hints_node_create(struct objagg_hints *objagg_hints,
              struct objagg_obj *objagg_obj, size_t obj_size,
              struct objagg_hints_node *parent_hnode)
 {
     unsigned int user_count = objagg_obj->stats.user_count;
     struct objagg_hints_node *hnode;
     int err;
 
     hnode = kzalloc(sizeof(*hnode) + obj_size, GFP_KERNEL);
     if (!hnode)
         return ERR_PTR(-ENOMEM);
     memcpy(hnode->obj, &objagg_obj->obj, obj_size);
     hnode->stats_info.stats.user_count = user_count;
     hnode->stats_info.stats.delta_user_count = user_count;
     if (parent_hnode) {
         parent_hnode->stats_info.stats.delta_user_count += user_count;
     } else {
         hnode->root_id = objagg_hints->root_count++;
         hnode->stats_info.is_root = true;
     }
     hnode->stats_info.objagg_obj = objagg_obj;
 
     err = rhashtable_insert_fast(&objagg_hints->node_ht, &hnode->ht_node,
                      objagg_hints->ht_params);
     if (err)
         goto err_ht_insert;
 
     list_add(&hnode->list, &objagg_hints->node_list);
     hnode->parent = parent_hnode;
     objagg_hints->node_count++;
 
     return hnode;
 
 err_ht_insert:
     kfree(hnode);
     return ERR_PTR(err);
 }
 
 static void objagg_hints_flush(struct objagg_hints *objagg_hints)
 {
     struct objagg_hints_node *hnode, *tmp;
 
     list_for_each_entry_safe(hnode, tmp, &objagg_hints->node_list, list) {
         list_del(&hnode->list);
         rhashtable_remove_fast(&objagg_hints->node_ht, &hnode->ht_node,
                        objagg_hints->ht_params);
         kfree(hnode);
     }
 }
 
 struct objagg_tmp_node {
     struct objagg_obj *objagg_obj;
     bool crossed_out;
 };
 
 struct objagg_tmp_graph {
     struct objagg_tmp_node *nodes;
     unsigned long nodes_count;
     unsigned long *edges;
 };
 
 static int objagg_tmp_graph_edge_index(struct objagg_tmp_graph *graph,
                        int parent_index, int index)
 {
     return index * graph->nodes_count + parent_index;
 }
 
 static void objagg_tmp_graph_edge_set(struct objagg_tmp_graph *graph,
                       int parent_index, int index)
 {
     int edge_index = objagg_tmp_graph_edge_index(graph, index,
                              parent_index);
 
     __set_bit(edge_index, graph->edges);
 }
 
 static bool objagg_tmp_graph_is_edge(struct objagg_tmp_graph *graph,
                      int parent_index, int index)
 {
     int edge_index = objagg_tmp_graph_edge_index(graph, index,
                              parent_index);
 
     return test_bit(edge_index, graph->edges);
 }
 
 static unsigned int objagg_tmp_graph_node_weight(struct objagg_tmp_graph *graph,
                          unsigned int index)
 {
     struct objagg_tmp_node *node = &graph->nodes[index];
     unsigned int weight = node->objagg_obj->stats.user_count;
     int j;
 
     /* Node weight is sum of node users and all other nodes users
      * that this node can represent with delta.
      */
 
     for (j = 0; j < graph->nodes_count; j++) {
         if (!objagg_tmp_graph_is_edge(graph, index, j))
             continue;
         node = &graph->nodes[j];
         if (node->crossed_out)
             continue;
         weight += node->objagg_obj->stats.user_count;
     }
     return weight;
 }
 
 static int objagg_tmp_graph_node_max_weight(struct objagg_tmp_graph *graph)
 {
     struct objagg_tmp_node *node;
     unsigned int max_weight = 0;
     unsigned int weight;
     int max_index = -1;
     int i;
 
     for (i = 0; i < graph->nodes_count; i++) {
         node = &graph->nodes[i];
         if (node->crossed_out)
             continue;
         weight = objagg_tmp_graph_node_weight(graph, i);
         if (weight >= max_weight) {
             max_weight = weight;
             max_index = i;
         }
     }
     return max_index;
 }
 
 static struct objagg_tmp_graph *objagg_tmp_graph_create(struct objagg *objagg)
 {
     unsigned int nodes_count = objagg->obj_count;
     struct objagg_tmp_graph *graph;
     struct objagg_tmp_node *node;
     struct objagg_tmp_node *pnode;
     struct objagg_obj *objagg_obj;
     int i, j;
 
     graph = kzalloc(sizeof(*graph), GFP_KERNEL);
     if (!graph)
         return NULL;
 
     graph->nodes = kcalloc(nodes_count, sizeof(*graph->nodes), GFP_KERNEL);
     if (!graph->nodes)
         goto err_nodes_alloc;
     graph->nodes_count = nodes_count;
 
     graph->edges = bitmap_zalloc(nodes_count * nodes_count, GFP_KERNEL);
     if (!graph->edges)
         goto err_edges_alloc;
 
     i = 0;
     list_for_each_entry(objagg_obj, &objagg->obj_list, list) {
         node = &graph->nodes[i++];
         node->objagg_obj = objagg_obj;
     }
 
     /* Assemble a temporary graph. Insert edge X->Y in case Y can be
      * in delta of X.
      */
     for (i = 0; i < nodes_count; i++) {
         for (j = 0; j < nodes_count; j++) {
             if (i == j)
                 continue;
             pnode = &graph->nodes[i];
             node = &graph->nodes[j];
             if (objagg->ops->delta_check(objagg->priv,
                              pnode->objagg_obj->obj,
                              node->objagg_obj->obj)) {
                 objagg_tmp_graph_edge_set(graph, i, j);
 
             }
         }
     }
     return graph;
 
 err_edges_alloc:
     kfree(graph->nodes);
 err_nodes_alloc:
     kfree(graph);
     return NULL;
 }
 
 static void objagg_tmp_graph_destroy(struct objagg_tmp_graph *graph)
 {
     bitmap_free(graph->edges);
     kfree(graph->nodes);
     kfree(graph);
 }
 
 static int
 objagg_opt_simple_greedy_fillup_hints(struct objagg_hints *objagg_hints,
                       struct objagg *objagg)
 {
     struct objagg_hints_node *hnode, *parent_hnode;
     struct objagg_tmp_graph *graph;
     struct objagg_tmp_node *node;
     int index;
     int j;
     int err;
 
     graph = objagg_tmp_graph_create(objagg);
     if (!graph)
         return -ENOMEM;
 
     /* Find the nodes from the ones that can accommodate most users
      * and cross them out of the graph. Save them to the hint list.
      */
     while ((index = objagg_tmp_graph_node_max_weight(graph)) != -1) {
         node = &graph->nodes[index];
         node->crossed_out = true;
         hnode = objagg_hints_node_create(objagg_hints,
                          node->objagg_obj,
                          objagg->ops->obj_size,
                          NULL);
         if (IS_ERR(hnode)) {
             err = PTR_ERR(hnode);
             goto out;
         }
         parent_hnode = hnode;
         for (j = 0; j < graph->nodes_count; j++) {
             if (!objagg_tmp_graph_is_edge(graph, index, j))
                 continue;
             node = &graph->nodes[j];
             if (node->crossed_out)
                 continue;
             node->crossed_out = true;
             hnode = objagg_hints_node_create(objagg_hints,
                              node->objagg_obj,
                              objagg->ops->obj_size,
                              parent_hnode);
             if (IS_ERR(hnode)) {
                 err = PTR_ERR(hnode);
                 goto out;
             }
         }
     }
 
     err = 0;
 out:
     objagg_tmp_graph_destroy(graph);
     return err;
 }
 
 struct objagg_opt_algo {
     int (*fillup_hints)(struct objagg_hints *objagg_hints,
                 struct objagg *objagg);
 };
 
 static const struct objagg_opt_algo objagg_opt_simple_greedy = {
     .fillup_hints = objagg_opt_simple_greedy_fillup_hints,
 };
 
 
 static const struct objagg_opt_algo *objagg_opt_algos[] = {
     [OBJAGG_OPT_ALGO_SIMPLE_GREEDY] = &objagg_opt_simple_greedy,
 };
 
 static int objagg_hints_obj_cmp(struct rhashtable_compare_arg *arg,
                 const void *obj)
 {
     struct rhashtable *ht = arg->ht;
     struct objagg_hints *objagg_hints =
             container_of(ht, struct objagg_hints, node_ht);
     const struct objagg_ops *ops = objagg_hints->ops;
     const char *ptr = obj;
 
     ptr += ht->p.key_offset;
     return ops->hints_obj_cmp ? ops->hints_obj_cmp(ptr, arg->key) :
                     memcmp(ptr, arg->key, ht->p.key_len);
 }
 
 /**
  * objagg_hints_get - obtains hints instance
  * @objagg:     objagg instance
  * @opt_algo_type:  type of hints finding algorithm
  *
  * Note: all locking must be provided by the caller.
  *
  * According to the algo type, the existing objects of objagg instance
  * are going to be went-through to assemble an optimal tree. We call this
  * tree hints. These hints can be later on used for creation of
  * a new objagg instance. There, the future object creations are going
  * to be consulted with these hints in order to find out, where exactly
  * the new object should be put as a root or delta.
  *
  * Returns a pointer to hints instance in case of success,
  * otherwise it returns pointer error using ERR_PTR macro.
  */
 struct objagg_hints *objagg_hints_get(struct objagg *objagg,
                       enum objagg_opt_algo_type opt_algo_type)
 {
     const struct objagg_opt_algo *algo = objagg_opt_algos[opt_algo_type];
     struct objagg_hints *objagg_hints;
     int err;
 
     objagg_hints = kzalloc(sizeof(*objagg_hints), GFP_KERNEL);
     if (!objagg_hints)
         return ERR_PTR(-ENOMEM);
 
     objagg_hints->ops = objagg->ops;
     objagg_hints->refcount = 1;
 
     INIT_LIST_HEAD(&objagg_hints->node_list);
 
     objagg_hints->ht_params.key_len = objagg->ops->obj_size;
     objagg_hints->ht_params.key_offset =
                 offsetof(struct objagg_hints_node, obj);
     objagg_hints->ht_params.head_offset =
                 offsetof(struct objagg_hints_node, ht_node);
     objagg_hints->ht_params.obj_cmpfn = objagg_hints_obj_cmp;
 
     err = rhashtable_init(&objagg_hints->node_ht, &objagg_hints->ht_params);
     if (err)
         goto err_rhashtable_init;
 
     err = algo->fillup_hints(objagg_hints, objagg);
     if (err)
         goto err_fillup_hints;
 
     if (WARN_ON(objagg_hints->node_count != objagg->obj_count)) {
         err = -EINVAL;
         goto err_node_count_check;
     }
 
     return objagg_hints;
 
 err_node_count_check:
 err_fillup_hints:
     objagg_hints_flush(objagg_hints);
     rhashtable_destroy(&objagg_hints->node_ht);
 err_rhashtable_init:
     kfree(objagg_hints);
     return ERR_PTR(err);
 }
 EXPORT_SYMBOL(objagg_hints_get);
 
 /**
  * objagg_hints_put - puts hints instance
  * @objagg_hints:   objagg hints instance
  *
  * Note: all locking must be provided by the caller.
  */
 void objagg_hints_put(struct objagg_hints *objagg_hints)
 {
     if (--objagg_hints->refcount)
         return;
     objagg_hints_flush(objagg_hints);
     rhashtable_destroy(&objagg_hints->node_ht);
     kfree(objagg_hints);
 }
 EXPORT_SYMBOL(objagg_hints_put);
 
 /**
  * objagg_hints_stats_get - obtains stats of the hints instance
  * @objagg_hints:   hints instance
  *
  * Note: all locking must be provided by the caller.
  *
  * The returned structure contains statistics of all objects
  * currently in use, ordered by following rules:
  * 1) Root objects are always on lower indexes than the rest.
  * 2) Objects with higher delta user count are always on lower
  *    indexes.
  * 3) In case multiple objects have the same delta user count,
  *    the objects are ordered by user count.
  *
  * Returns a pointer to stats instance in case of success,
  * otherwise it returns pointer error using ERR_PTR macro.
  */
 const struct objagg_stats *
 objagg_hints_stats_get(struct objagg_hints *objagg_hints)
 {
     struct objagg_stats *objagg_stats;
     struct objagg_hints_node *hnode;
     int i;
 
     objagg_stats = kzalloc(struct_size(objagg_stats, stats_info,
                        objagg_hints->node_count),
                    GFP_KERNEL);
     if (!objagg_stats)
         return ERR_PTR(-ENOMEM);
 
     i = 0;
     list_for_each_entry(hnode, &objagg_hints->node_list, list) {
         memcpy(&objagg_stats->stats_info[i], &hnode->stats_info,
                sizeof(objagg_stats->stats_info[0]));
         if (objagg_stats->stats_info[i].is_root)
             objagg_stats->root_count++;
         i++;
     }
     objagg_stats->stats_info_count = i;
 
     sort(objagg_stats->stats_info, objagg_stats->stats_info_count,
          sizeof(struct objagg_obj_stats_info),
          objagg_stats_info_sort_cmp_func, NULL);
 
     return objagg_stats;
 }
 EXPORT_SYMBOL(objagg_hints_stats_get);
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Jiri Pirko <jiri@mellanox.com>");
 MODULE_DESCRIPTION("Object aggregation manager");

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