X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Frculfhash.h;h=8ee9bdd9ebd9eb368e139b26a3ab51d167d8ea99;hp=99b43a8ba0ec4b178b60f1e9491b7176a3204f1f;hb=f0c29ed7ca7129056f5c757a9fbcbbfa8c14da44;hpb=cc4fcb1069347d2b5fbf71a61e7c1712df9a177a diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h index 99b43a8..8ee9bdd 100644 --- a/urcu/rculfhash.h +++ b/urcu/rculfhash.h @@ -1,6 +1,28 @@ #ifndef _URCU_RCULFHASH_H #define _URCU_RCULFHASH_H +/* + * urcu/rculfhash.h + * + * Userspace RCU library - Lock-Free RCU Hash Table + * + * Copyright 2011 - Mathieu Desnoyers + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + #include #include @@ -8,10 +30,14 @@ extern "C" { #endif +/* + * struct rcu_ht_node and struct _rcu_ht_node should be aligned on + * 4-bytes boundaries because the two lower bits are used as flags. + */ + struct _rcu_ht_node { - struct rcu_ht_node *next; + struct rcu_ht_node *next; /* ptr | DUMMY_FLAG | REMOVED_FLAG */ unsigned long reverse_hash; - unsigned int dummy; }; struct rcu_ht_node { @@ -35,16 +61,20 @@ typedef unsigned long (*ht_hash_fct)(void *key, size_t length, typedef unsigned long (*ht_compare_fct)(void *key1, size_t key1_len, void *key2, size_t key2_len); +/* + * ht_node_init - initialize a hash table node + */ static inline void ht_node_init(struct rcu_ht_node *node, void *key, size_t key_len) { node->key = key; node->key_len = key_len; - node->p.dummy = 0; } /* + * ht_new - allocate a hash table. + * * init_size must be power of two. */ struct rcu_ht *ht_new(ht_hash_fct hash_fct, @@ -54,29 +84,70 @@ struct rcu_ht *ht_new(ht_hash_fct hash_fct, void (*ht_call_rcu)(struct rcu_head *head, void (*func)(struct rcu_head *head))); +/* + * ht_destroy - destroy a hash table. + */ int ht_destroy(struct rcu_ht *ht); -/* Count the number of nodes in the hash table. Call with rcu_read_lock held. */ + +/* + * ht_count_nodes - count the number of nodes in the hash table. + * + * Call with rcu_read_lock held. + */ void ht_count_nodes(struct rcu_ht *ht, unsigned long *count, unsigned long *removed); -/* Call with rcu_read_lock held. */ +/* + * ht_lookup - lookup a node by key. + * + * Returns NULL if not found. + * Call with rcu_read_lock held. + */ struct rcu_ht_node *ht_lookup(struct rcu_ht *ht, void *key, size_t key_len); -/* Call with rcu_read_lock held. */ -void ht_add(struct rcu_ht *ht, struct rcu_ht_node *node); +/* + * ht_next - get the next item with same key (after a lookup). + * + * Returns NULL if no following node exists with same key. + * RCU read-side lock must be held across ht_lookup and ht_next calls, and also + * between ht_next calls using the node returned by a previous ht_next. + * Call with rcu_read_lock held. + */ +struct rcu_ht_node *ht_next(struct rcu_ht *ht, struct rcu_ht_node *node); /* + * ht_add - add a node to the hash table. + * * Call with rcu_read_lock held. + */ +void ht_add(struct rcu_ht *ht, struct rcu_ht_node *node); + +/* + * ht_add_unique - add a node to hash table, if key is not present. + * * Returns the node added upon success. * Returns the unique node already present upon failure. If ht_add_unique fails, * the node passed as parameter should be freed by the caller. + * Call with rcu_read_lock held. */ struct rcu_ht_node *ht_add_unique(struct rcu_ht *ht, struct rcu_ht_node *node); -/* Call with rcu_read_lock held. */ +/* + * ht_remove - remove node from hash table. + * + * Node can be looked up with ht_lookup. RCU read-side lock must be held between + * lookup and removal. + * Call with rcu_read_lock held. + */ int ht_remove(struct rcu_ht *ht, struct rcu_ht_node *node); +/* + * ht_resize - Force a hash table resize + * @growth: growth order (current size is multiplied by 2^growth) + * + * Currently, only expand operation is supported (growth >= 0). + */ void ht_resize(struct rcu_ht *ht, int growth); #ifdef __cplusplus