Commit | Line | Data |
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c6c8fea2 | 1 | /* |
64afe353 | 2 | * Copyright (C) 2006-2011 B.A.T.M.A.N. contributors: |
c6c8fea2 SE |
3 | * |
4 | * Simon Wunderlich, Marek Lindner | |
5 | * | |
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. | |
9 | * | |
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. | |
14 | * | |
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 | |
18 | * 02110-1301, USA | |
19 | * | |
20 | */ | |
21 | ||
22 | #ifndef _NET_BATMAN_ADV_HASH_H_ | |
23 | #define _NET_BATMAN_ADV_HASH_H_ | |
24 | ||
25 | #include <linux/list.h> | |
26 | ||
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 | |
30 | * same */ | |
747e4221 | 31 | typedef int (*hashdata_compare_cb)(const struct hlist_node *, const void *); |
c6c8fea2 SE |
32 | |
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 */ | |
747e4221 | 36 | typedef int (*hashdata_choose_cb)(const void *, int); |
7aadf889 | 37 | typedef void (*hashdata_free_cb)(struct hlist_node *, void *); |
c6c8fea2 SE |
38 | |
39 | struct hashtable_t { | |
fb778ea1 ML |
40 | struct hlist_head *table; /* the hashtable itself with the buckets */ |
41 | spinlock_t *list_locks; /* spinlock for each hash list entry */ | |
c6c8fea2 SE |
42 | int size; /* size of hashtable */ |
43 | }; | |
44 | ||
45 | /* allocates and clears the hash */ | |
46 | struct hashtable_t *hash_new(int size); | |
47 | ||
c6c8fea2 SE |
48 | /* free only the hashtable and the hash itself. */ |
49 | void hash_destroy(struct hashtable_t *hash); | |
50 | ||
51 | /* remove the hash structure. if hashdata_free_cb != NULL, this function will be | |
52 | * called to remove the elements inside of the hash. if you don't remove the | |
53 | * elements, memory might be leaked. */ | |
54 | static inline void hash_delete(struct hashtable_t *hash, | |
55 | hashdata_free_cb free_cb, void *arg) | |
56 | { | |
57 | struct hlist_head *head; | |
7aadf889 | 58 | struct hlist_node *node, *node_tmp; |
fb778ea1 | 59 | spinlock_t *list_lock; /* spinlock to protect write access */ |
c6c8fea2 SE |
60 | int i; |
61 | ||
62 | for (i = 0; i < hash->size; i++) { | |
63 | head = &hash->table[i]; | |
fb778ea1 | 64 | list_lock = &hash->list_locks[i]; |
c6c8fea2 | 65 | |
fb778ea1 | 66 | spin_lock_bh(list_lock); |
7aadf889 ML |
67 | hlist_for_each_safe(node, node_tmp, head) { |
68 | hlist_del_rcu(node); | |
c6c8fea2 | 69 | |
7aadf889 ML |
70 | if (free_cb) |
71 | free_cb(node, arg); | |
c6c8fea2 | 72 | } |
fb778ea1 | 73 | spin_unlock_bh(list_lock); |
c6c8fea2 SE |
74 | } |
75 | ||
76 | hash_destroy(hash); | |
77 | } | |
78 | ||
1a1f37d9 AQ |
79 | /** |
80 | * hash_add - adds data to the hashtable | |
81 | * @hash: storage hash table | |
82 | * @compare: callback to determine if 2 hash elements are identical | |
83 | * @choose: callback calculating the hash index | |
84 | * @data: data passed to the aforementioned callbacks as argument | |
85 | * @data_node: to be added element | |
86 | * | |
87 | * Returns 0 on success, 1 if the element already is in the hash | |
88 | * and -1 on error. | |
89 | */ | |
90 | ||
c6c8fea2 SE |
91 | static inline int hash_add(struct hashtable_t *hash, |
92 | hashdata_compare_cb compare, | |
7aadf889 | 93 | hashdata_choose_cb choose, |
747e4221 | 94 | const void *data, struct hlist_node *data_node) |
c6c8fea2 | 95 | { |
1a1f37d9 | 96 | int index, ret = -1; |
c6c8fea2 | 97 | struct hlist_head *head; |
7aadf889 | 98 | struct hlist_node *node; |
fb778ea1 | 99 | spinlock_t *list_lock; /* spinlock to protect write access */ |
c6c8fea2 SE |
100 | |
101 | if (!hash) | |
1a1f37d9 | 102 | goto out; |
c6c8fea2 SE |
103 | |
104 | index = choose(data, hash->size); | |
105 | head = &hash->table[index]; | |
fb778ea1 | 106 | list_lock = &hash->list_locks[index]; |
c6c8fea2 | 107 | |
fb778ea1 | 108 | rcu_read_lock(); |
7aadf889 ML |
109 | __hlist_for_each_rcu(node, head) { |
110 | if (!compare(node, data)) | |
111 | continue; | |
112 | ||
1a1f37d9 | 113 | ret = 1; |
7aadf889 | 114 | goto err_unlock; |
c6c8fea2 | 115 | } |
fb778ea1 | 116 | rcu_read_unlock(); |
c6c8fea2 SE |
117 | |
118 | /* no duplicate found in list, add new element */ | |
fb778ea1 | 119 | spin_lock_bh(list_lock); |
7aadf889 | 120 | hlist_add_head_rcu(data_node, head); |
fb778ea1 | 121 | spin_unlock_bh(list_lock); |
c6c8fea2 | 122 | |
1a1f37d9 AQ |
123 | ret = 0; |
124 | goto out; | |
fb778ea1 ML |
125 | |
126 | err_unlock: | |
127 | rcu_read_unlock(); | |
1a1f37d9 AQ |
128 | out: |
129 | return ret; | |
c6c8fea2 SE |
130 | } |
131 | ||
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 | |
135 | * comparing. */ | |
136 | static inline void *hash_remove(struct hashtable_t *hash, | |
137 | hashdata_compare_cb compare, | |
138 | hashdata_choose_cb choose, void *data) | |
139 | { | |
140 | size_t index; | |
7aadf889 | 141 | struct hlist_node *node; |
c6c8fea2 | 142 | struct hlist_head *head; |
fb778ea1 | 143 | void *data_save = NULL; |
c6c8fea2 SE |
144 | |
145 | index = choose(data, hash->size); | |
146 | head = &hash->table[index]; | |
147 | ||
fb778ea1 | 148 | spin_lock_bh(&hash->list_locks[index]); |
7aadf889 ML |
149 | hlist_for_each(node, head) { |
150 | if (!compare(node, data)) | |
151 | continue; | |
152 | ||
153 | data_save = node; | |
154 | hlist_del_rcu(node); | |
155 | break; | |
c6c8fea2 | 156 | } |
fb778ea1 | 157 | spin_unlock_bh(&hash->list_locks[index]); |
c6c8fea2 | 158 | |
fb778ea1 | 159 | return data_save; |
c6c8fea2 SE |
160 | } |
161 | ||
c6c8fea2 | 162 | #endif /* _NET_BATMAN_ADV_HASH_H_ */ |