1 /* Copyright (C) 2006-2012 B.A.T.M.A.N. contributors:
3 * Simon Wunderlich, Marek Lindner
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 #ifndef _NET_BATMAN_ADV_HASH_H_
21 #define _NET_BATMAN_ADV_HASH_H_
23 #include <linux/list.h>
25 /* callback to a compare function. should compare 2 element datas for their
26 * keys, return 0 if same and not 0 if not same
28 typedef int (*hashdata_compare_cb)(const struct hlist_node *, const void *);
30 /* the hashfunction, should return an index
31 * based on the key in the data of the first
32 * argument and the size the second
34 typedef uint32_t (*hashdata_choose_cb)(const void *, uint32_t);
35 typedef void (*hashdata_free_cb)(struct hlist_node *, void *);
38 struct hlist_head *table; /* the hashtable itself with the buckets */
39 spinlock_t *list_locks; /* spinlock for each hash list entry */
40 uint32_t size; /* size of hashtable */
43 /* allocates and clears the hash */
44 struct hashtable_t *batadv_hash_new(uint32_t size);
46 /* set class key for all locks */
47 void batadv_hash_set_lock_class(struct hashtable_t *hash,
48 struct lock_class_key *key);
50 /* free only the hashtable and the hash itself. */
51 void batadv_hash_destroy(struct hashtable_t *hash);
53 /* remove the hash structure. if hashdata_free_cb != NULL, this function will be
54 * called to remove the elements inside of the hash. if you don't remove the
55 * elements, memory might be leaked.
57 static inline void batadv_hash_delete(struct hashtable_t *hash,
58 hashdata_free_cb free_cb, void *arg)
60 struct hlist_head *head;
61 struct hlist_node *node, *node_tmp;
62 spinlock_t *list_lock; /* spinlock to protect write access */
65 for (i = 0; i < hash->size; i++) {
66 head = &hash->table[i];
67 list_lock = &hash->list_locks[i];
69 spin_lock_bh(list_lock);
70 hlist_for_each_safe(node, node_tmp, head) {
76 spin_unlock_bh(list_lock);
79 batadv_hash_destroy(hash);
82 /* hash_add - adds data to the hashtable
83 * @hash: storage hash table
84 * @compare: callback to determine if 2 hash elements are identical
85 * @choose: callback calculating the hash index
86 * @data: data passed to the aforementioned callbacks as argument
87 * @data_node: to be added element
89 * Returns 0 on success, 1 if the element already is in the hash
92 static inline int batadv_hash_add(struct hashtable_t *hash,
93 hashdata_compare_cb compare,
94 hashdata_choose_cb choose,
96 struct hlist_node *data_node)
100 struct hlist_head *head;
101 struct hlist_node *node;
102 spinlock_t *list_lock; /* spinlock to protect write access */
107 index = choose(data, hash->size);
108 head = &hash->table[index];
109 list_lock = &hash->list_locks[index];
111 spin_lock_bh(list_lock);
113 hlist_for_each(node, head) {
114 if (!compare(node, data))
121 /* no duplicate found in list, add new element */
122 hlist_add_head_rcu(data_node, head);
127 spin_unlock_bh(list_lock);
132 /* removes data from hash, if found. returns pointer do data on success, so you
133 * can remove the used structure yourself, or NULL on error . data could be the
134 * structure you use with just the key filled, we just need the key for
137 static inline void *batadv_hash_remove(struct hashtable_t *hash,
138 hashdata_compare_cb compare,
139 hashdata_choose_cb choose, void *data)
142 struct hlist_node *node;
143 struct hlist_head *head;
144 void *data_save = NULL;
146 index = choose(data, hash->size);
147 head = &hash->table[index];
149 spin_lock_bh(&hash->list_locks[index]);
150 hlist_for_each(node, head) {
151 if (!compare(node, data))
158 spin_unlock_bh(&hash->list_locks[index]);
163 #endif /* _NET_BATMAN_ADV_HASH_H_ */