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1 | /* Copyright (C) 2006-2015 B.A.T.M.A.N. contributors: | |
2 | * | |
3 | * Simon Wunderlich, Marek Lindner | |
4 | * | |
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. | |
8 | * | |
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. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, see <http://www.gnu.org/licenses/>. | |
16 | */ | |
17 | ||
18 | #ifndef _NET_BATMAN_ADV_HASH_H_ | |
19 | #define _NET_BATMAN_ADV_HASH_H_ | |
20 | ||
21 | #include "main.h" | |
22 | ||
23 | #include <linux/compiler.h> | |
24 | #include <linux/list.h> | |
25 | #include <linux/rculist.h> | |
26 | #include <linux/spinlock.h> | |
27 | #include <linux/stddef.h> | |
28 | #include <linux/types.h> | |
29 | ||
30 | struct lock_class_key; | |
31 | ||
32 | /* callback to a compare function. should compare 2 element datas for their | |
33 | * keys, return 0 if same and not 0 if not same | |
34 | */ | |
35 | typedef int (*batadv_hashdata_compare_cb)(const struct hlist_node *, | |
36 | const void *); | |
37 | ||
38 | /* the hashfunction, should return an index | |
39 | * based on the key in the data of the first | |
40 | * argument and the size the second | |
41 | */ | |
42 | typedef u32 (*batadv_hashdata_choose_cb)(const void *, u32); | |
43 | typedef void (*batadv_hashdata_free_cb)(struct hlist_node *, void *); | |
44 | ||
45 | struct batadv_hashtable { | |
46 | struct hlist_head *table; /* the hashtable itself with the buckets */ | |
47 | spinlock_t *list_locks; /* spinlock for each hash list entry */ | |
48 | u32 size; /* size of hashtable */ | |
49 | }; | |
50 | ||
51 | /* allocates and clears the hash */ | |
52 | struct batadv_hashtable *batadv_hash_new(u32 size); | |
53 | ||
54 | /* set class key for all locks */ | |
55 | void batadv_hash_set_lock_class(struct batadv_hashtable *hash, | |
56 | struct lock_class_key *key); | |
57 | ||
58 | /* free only the hashtable and the hash itself. */ | |
59 | void batadv_hash_destroy(struct batadv_hashtable *hash); | |
60 | ||
61 | /* remove the hash structure. if hashdata_free_cb != NULL, this function will be | |
62 | * called to remove the elements inside of the hash. if you don't remove the | |
63 | * elements, memory might be leaked. | |
64 | */ | |
65 | static inline void batadv_hash_delete(struct batadv_hashtable *hash, | |
66 | batadv_hashdata_free_cb free_cb, | |
67 | void *arg) | |
68 | { | |
69 | struct hlist_head *head; | |
70 | struct hlist_node *node, *node_tmp; | |
71 | spinlock_t *list_lock; /* spinlock to protect write access */ | |
72 | u32 i; | |
73 | ||
74 | for (i = 0; i < hash->size; i++) { | |
75 | head = &hash->table[i]; | |
76 | list_lock = &hash->list_locks[i]; | |
77 | ||
78 | spin_lock_bh(list_lock); | |
79 | hlist_for_each_safe(node, node_tmp, head) { | |
80 | hlist_del_rcu(node); | |
81 | ||
82 | if (free_cb) | |
83 | free_cb(node, arg); | |
84 | } | |
85 | spin_unlock_bh(list_lock); | |
86 | } | |
87 | ||
88 | batadv_hash_destroy(hash); | |
89 | } | |
90 | ||
91 | /** | |
92 | * batadv_hash_add - adds data to the hashtable | |
93 | * @hash: storage hash table | |
94 | * @compare: callback to determine if 2 hash elements are identical | |
95 | * @choose: callback calculating the hash index | |
96 | * @data: data passed to the aforementioned callbacks as argument | |
97 | * @data_node: to be added element | |
98 | * | |
99 | * Returns 0 on success, 1 if the element already is in the hash | |
100 | * and -1 on error. | |
101 | */ | |
102 | static inline int batadv_hash_add(struct batadv_hashtable *hash, | |
103 | batadv_hashdata_compare_cb compare, | |
104 | batadv_hashdata_choose_cb choose, | |
105 | const void *data, | |
106 | struct hlist_node *data_node) | |
107 | { | |
108 | u32 index; | |
109 | int ret = -1; | |
110 | struct hlist_head *head; | |
111 | struct hlist_node *node; | |
112 | spinlock_t *list_lock; /* spinlock to protect write access */ | |
113 | ||
114 | if (!hash) | |
115 | goto out; | |
116 | ||
117 | index = choose(data, hash->size); | |
118 | head = &hash->table[index]; | |
119 | list_lock = &hash->list_locks[index]; | |
120 | ||
121 | spin_lock_bh(list_lock); | |
122 | ||
123 | hlist_for_each(node, head) { | |
124 | if (!compare(node, data)) | |
125 | continue; | |
126 | ||
127 | ret = 1; | |
128 | goto unlock; | |
129 | } | |
130 | ||
131 | /* no duplicate found in list, add new element */ | |
132 | hlist_add_head_rcu(data_node, head); | |
133 | ||
134 | ret = 0; | |
135 | ||
136 | unlock: | |
137 | spin_unlock_bh(list_lock); | |
138 | out: | |
139 | return ret; | |
140 | } | |
141 | ||
142 | /* removes data from hash, if found. returns pointer do data on success, so you | |
143 | * can remove the used structure yourself, or NULL on error . data could be the | |
144 | * structure you use with just the key filled, we just need the key for | |
145 | * comparing. | |
146 | */ | |
147 | static inline void *batadv_hash_remove(struct batadv_hashtable *hash, | |
148 | batadv_hashdata_compare_cb compare, | |
149 | batadv_hashdata_choose_cb choose, | |
150 | void *data) | |
151 | { | |
152 | u32 index; | |
153 | struct hlist_node *node; | |
154 | struct hlist_head *head; | |
155 | void *data_save = NULL; | |
156 | ||
157 | index = choose(data, hash->size); | |
158 | head = &hash->table[index]; | |
159 | ||
160 | spin_lock_bh(&hash->list_locks[index]); | |
161 | hlist_for_each(node, head) { | |
162 | if (!compare(node, data)) | |
163 | continue; | |
164 | ||
165 | data_save = node; | |
166 | hlist_del_rcu(node); | |
167 | break; | |
168 | } | |
169 | spin_unlock_bh(&hash->list_locks[index]); | |
170 | ||
171 | return data_save; | |
172 | } | |
173 | ||
174 | #endif /* _NET_BATMAN_ADV_HASH_H_ */ |