Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tree: 2c53040f01
Fetching contributors…

Cannot retrieve contributors at this time

file 167 lines (139 sloc) 4.702 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167
/* Copyright (C) 2006-2012 B.A.T.M.A.N. contributors:
*
* Simon Wunderlich, Marek Lindner
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
*/

#ifndef _NET_BATMAN_ADV_HASH_H_
#define _NET_BATMAN_ADV_HASH_H_

#include <linux/list.h>

/* callback to a compare function. should compare 2 element datas for their
* keys, return 0 if same and not 0 if not same
*/
typedef int (*batadv_hashdata_compare_cb)(const struct hlist_node *,
const void *);

/* the hashfunction, should return an index
* based on the key in the data of the first
* argument and the size the second
*/
typedef uint32_t (*batadv_hashdata_choose_cb)(const void *, uint32_t);
typedef void (*batadv_hashdata_free_cb)(struct hlist_node *, void *);

struct batadv_hashtable {
struct hlist_head *table; /* the hashtable itself with the buckets */
spinlock_t *list_locks; /* spinlock for each hash list entry */
uint32_t size; /* size of hashtable */
};

/* allocates and clears the hash */
struct batadv_hashtable *batadv_hash_new(uint32_t size);

/* set class key for all locks */
void batadv_hash_set_lock_class(struct batadv_hashtable *hash,
struct lock_class_key *key);

/* free only the hashtable and the hash itself. */
void batadv_hash_destroy(struct batadv_hashtable *hash);

/* remove the hash structure. if hashdata_free_cb != NULL, this function will be
* called to remove the elements inside of the hash. if you don't remove the
* elements, memory might be leaked.
*/
static inline void batadv_hash_delete(struct batadv_hashtable *hash,
batadv_hashdata_free_cb free_cb,
void *arg)
{
struct hlist_head *head;
struct hlist_node *node, *node_tmp;
spinlock_t *list_lock; /* spinlock to protect write access */
uint32_t i;

for (i = 0; i < hash->size; i++) {
head = &hash->table[i];
list_lock = &hash->list_locks[i];

spin_lock_bh(list_lock);
hlist_for_each_safe(node, node_tmp, head) {
hlist_del_rcu(node);

if (free_cb)
free_cb(node, arg);
}
spin_unlock_bh(list_lock);
}

batadv_hash_destroy(hash);
}

/**
* batadv_hash_add - adds data to the hashtable
* @hash: storage hash table
* @compare: callback to determine if 2 hash elements are identical
* @choose: callback calculating the hash index
* @data: data passed to the aforementioned callbacks as argument
* @data_node: to be added element
*
* Returns 0 on success, 1 if the element already is in the hash
* and -1 on error.
*/
static inline int batadv_hash_add(struct batadv_hashtable *hash,
batadv_hashdata_compare_cb compare,
batadv_hashdata_choose_cb choose,
const void *data,
struct hlist_node *data_node)
{
uint32_t index;
int ret = -1;
struct hlist_head *head;
struct hlist_node *node;
spinlock_t *list_lock; /* spinlock to protect write access */

if (!hash)
goto out;

index = choose(data, hash->size);
head = &hash->table[index];
list_lock = &hash->list_locks[index];

spin_lock_bh(list_lock);

hlist_for_each(node, head) {
if (!compare(node, data))
continue;

ret = 1;
goto unlock;
}

/* no duplicate found in list, add new element */
hlist_add_head_rcu(data_node, head);

ret = 0;

unlock:
spin_unlock_bh(list_lock);
out:
return ret;
}

/* removes data from hash, if found. returns pointer do data on success, so you
* can remove the used structure yourself, or NULL on error . data could be the
* structure you use with just the key filled, we just need the key for
* comparing.
*/
static inline void *batadv_hash_remove(struct batadv_hashtable *hash,
batadv_hashdata_compare_cb compare,
batadv_hashdata_choose_cb choose,
void *data)
{
uint32_t index;
struct hlist_node *node;
struct hlist_head *head;
void *data_save = NULL;

index = choose(data, hash->size);
head = &hash->table[index];

spin_lock_bh(&hash->list_locks[index]);
hlist_for_each(node, head) {
if (!compare(node, data))
continue;

data_save = node;
hlist_del_rcu(node);
break;
}
spin_unlock_bh(&hash->list_locks[index]);

return data_save;
}

#endif /* _NET_BATMAN_ADV_HASH_H_ */
Something went wrong with that request. Please try again.