diff options
Diffstat (limited to 'lib/objagg.c')
| -rw-r--r-- | lib/objagg.c | 501 |
1 files changed, 501 insertions, 0 deletions
diff --git a/lib/objagg.c b/lib/objagg.c new file mode 100644 index 000000000000..c9b457a91153 --- /dev/null +++ b/lib/objagg.c @@ -0,0 +1,501 @@ +// 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/list.h> +#include <linux/sort.h> +#include <linux/objagg.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/objagg.h> + +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 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 refcount; /* counts number of users of this object + * including nested objects + */ + struct objagg_obj_stats stats; + unsigned long obj[0]; +}; + +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) +{ + 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; + 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); + 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_create(struct objagg *objagg, + struct objagg_obj *objagg_obj) +{ + objagg_obj->root_priv = objagg->ops->root_create(objagg->priv, + objagg_obj->obj); + if (IS_ERR(objagg_obj->root_priv)) + return PTR_ERR(objagg_obj->root_priv); + + trace_objagg_obj_root_create(objagg, objagg_obj); + return 0; +} + +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); +} + +static int objagg_obj_init(struct objagg *objagg, + struct objagg_obj *objagg_obj) +{ + int err; + + /* 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); +} + +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 + * @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, void *priv) +{ + struct objagg *objagg; + int err; + + if (WARN_ON(!ops || !ops->root_create || !ops->root_destroy || + !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; + 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; + + 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); + WARN_ON(!list_empty(&objagg->obj_list)); + rhashtable_destroy(&objagg->obj_ht); + 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; + size_t alloc_size; + int i; + + alloc_size = sizeof(*objagg_stats) + + sizeof(objagg_stats->stats_info[0]) * objagg->obj_count; + objagg_stats = kzalloc(alloc_size, 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); + 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_puts - 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); + +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_AUTHOR("Jiri Pirko <jiri@mellanox.com>"); +MODULE_DESCRIPTION("Object aggregation manager"); |