2 * Copyright (C) 2006-2012 B.A.T.M.A.N. contributors:
4 * Simon Wunderlich, Marek Lindner
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of version 2 of the GNU General Public
8 * License as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 #ifndef _NET_BATMAN_ADV_HASH_H_
23 #define _NET_BATMAN_ADV_HASH_H_
25 #include <linux/list.h>
27 /* callback to a compare function. should
28 * compare 2 element datas for their keys,
29 * return 0 if same and not 0 if not
31 typedef int (*hashdata_compare_cb)(const struct hlist_node *, const void *);
33 /* the hashfunction, should return an index
34 * based on the key in the data of the first
35 * argument and the size the second */
36 typedef uint32_t (*hashdata_choose_cb)(const void *, uint32_t);
37 typedef void (*hashdata_free_cb)(struct hlist_node *, void *);
40 struct hlist_head *table; /* the hashtable itself with the buckets */
41 spinlock_t *list_locks; /* spinlock for each hash list entry */
42 uint32_t size; /* size of hashtable */
45 /* allocates and clears the hash */
46 struct hashtable_t *batadv_hash_new(uint32_t size);
48 /* set class key for all locks */
49 void batadv_hash_set_lock_class(struct hashtable_t *hash,
50 struct lock_class_key *key);
52 /* free only the hashtable and the hash itself. */
53 void batadv_hash_destroy(struct hashtable_t *hash);
55 /* remove the hash structure. if hashdata_free_cb != NULL, this function will be
56 * called to remove the elements inside of the hash. if you don't remove the
57 * elements, memory might be leaked. */
58 static inline void hash_delete(struct hashtable_t *hash,
59 hashdata_free_cb free_cb, void *arg)
61 struct hlist_head *head;
62 struct hlist_node *node, *node_tmp;
63 spinlock_t *list_lock; /* spinlock to protect write access */
66 for (i = 0; i < hash->size; i++) {
67 head = &hash->table[i];
68 list_lock = &hash->list_locks[i];
70 spin_lock_bh(list_lock);
71 hlist_for_each_safe(node, node_tmp, head) {
77 spin_unlock_bh(list_lock);
80 batadv_hash_destroy(hash);
84 * hash_add - adds data to the hashtable
85 * @hash: storage hash table
86 * @compare: callback to determine if 2 hash elements are identical
87 * @choose: callback calculating the hash index
88 * @data: data passed to the aforementioned callbacks as argument
89 * @data_node: to be added element
91 * Returns 0 on success, 1 if the element already is in the hash
95 static inline int hash_add(struct hashtable_t *hash,
96 hashdata_compare_cb compare,
97 hashdata_choose_cb choose,
98 const void *data, struct hlist_node *data_node)
102 struct hlist_head *head;
103 struct hlist_node *node;
104 spinlock_t *list_lock; /* spinlock to protect write access */
109 index = choose(data, hash->size);
110 head = &hash->table[index];
111 list_lock = &hash->list_locks[index];
113 spin_lock_bh(list_lock);
115 hlist_for_each(node, head) {
116 if (!compare(node, data))
123 /* no duplicate found in list, add new element */
124 hlist_add_head_rcu(data_node, head);
129 spin_unlock_bh(list_lock);
134 /* removes data from hash, if found. returns pointer do data on success, so you
135 * can remove the used structure yourself, or NULL on error . data could be the
136 * structure you use with just the key filled, we just need the key for
138 static inline void *hash_remove(struct hashtable_t *hash,
139 hashdata_compare_cb compare,
140 hashdata_choose_cb choose, void *data)
143 struct hlist_node *node;
144 struct hlist_head *head;
145 void *data_save = NULL;
147 index = choose(data, hash->size);
148 head = &hash->table[index];
150 spin_lock_bh(&hash->list_locks[index]);
151 hlist_for_each(node, head) {
152 if (!compare(node, data))
159 spin_unlock_bh(&hash->list_locks[index]);
164 #endif /* _NET_BATMAN_ADV_HASH_H_ */