Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame] | 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_ */ |