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 (*batadv_hashdata_compare_cb
)(const struct hlist_node
*,
31 /* the hashfunction, should return an index
32 * based on the key in the data of the first
33 * argument and the size the second
35 typedef uint32_t (*batadv_hashdata_choose_cb
)(const void *, uint32_t);
36 typedef void (*batadv_hashdata_free_cb
)(struct hlist_node
*, void *);
38 struct batadv_hashtable
{
39 struct hlist_head
*table
; /* the hashtable itself with the buckets */
40 spinlock_t
*list_locks
; /* spinlock for each hash list entry */
41 uint32_t size
; /* size of hashtable */
44 /* allocates and clears the hash */
45 struct batadv_hashtable
*batadv_hash_new(uint32_t size
);
47 /* set class key for all locks */
48 void batadv_hash_set_lock_class(struct batadv_hashtable
*hash
,
49 struct lock_class_key
*key
);
51 /* free only the hashtable and the hash itself. */
52 void batadv_hash_destroy(struct batadv_hashtable
*hash
);
54 /* remove the hash structure. if hashdata_free_cb != NULL, this function will be
55 * called to remove the elements inside of the hash. if you don't remove the
56 * elements, memory might be leaked.
58 static inline void batadv_hash_delete(struct batadv_hashtable
*hash
,
59 batadv_hashdata_free_cb free_cb
,
62 struct hlist_head
*head
;
63 struct hlist_node
*node
, *node_tmp
;
64 spinlock_t
*list_lock
; /* spinlock to protect write access */
67 for (i
= 0; i
< hash
->size
; i
++) {
68 head
= &hash
->table
[i
];
69 list_lock
= &hash
->list_locks
[i
];
71 spin_lock_bh(list_lock
);
72 hlist_for_each_safe(node
, node_tmp
, head
) {
78 spin_unlock_bh(list_lock
);
81 batadv_hash_destroy(hash
);
85 * batadv_hash_add - adds data to the hashtable
86 * @hash: storage hash table
87 * @compare: callback to determine if 2 hash elements are identical
88 * @choose: callback calculating the hash index
89 * @data: data passed to the aforementioned callbacks as argument
90 * @data_node: to be added element
92 * Returns 0 on success, 1 if the element already is in the hash
95 static inline int batadv_hash_add(struct batadv_hashtable
*hash
,
96 batadv_hashdata_compare_cb compare
,
97 batadv_hashdata_choose_cb choose
,
99 struct hlist_node
*data_node
)
103 struct hlist_head
*head
;
104 struct hlist_node
*node
;
105 spinlock_t
*list_lock
; /* spinlock to protect write access */
110 index
= choose(data
, hash
->size
);
111 head
= &hash
->table
[index
];
112 list_lock
= &hash
->list_locks
[index
];
114 spin_lock_bh(list_lock
);
116 hlist_for_each(node
, head
) {
117 if (!compare(node
, data
))
124 /* no duplicate found in list, add new element */
125 hlist_add_head_rcu(data_node
, head
);
130 spin_unlock_bh(list_lock
);
135 /* removes data from hash, if found. returns pointer do data on success, so you
136 * can remove the used structure yourself, or NULL on error . data could be the
137 * structure you use with just the key filled, we just need the key for
140 static inline void *batadv_hash_remove(struct batadv_hashtable
*hash
,
141 batadv_hashdata_compare_cb compare
,
142 batadv_hashdata_choose_cb choose
,
146 struct hlist_node
*node
;
147 struct hlist_head
*head
;
148 void *data_save
= NULL
;
150 index
= choose(data
, hash
->size
);
151 head
= &hash
->table
[index
];
153 spin_lock_bh(&hash
->list_locks
[index
]);
154 hlist_for_each(node
, head
) {
155 if (!compare(node
, data
))
162 spin_unlock_bh(&hash
->list_locks
[index
]);
167 #endif /* _NET_BATMAN_ADV_HASH_H_ */