| /* Copyright (C) 2006-2016 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, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #ifndef _NET_BATMAN_ADV_HASH_H_ |
| #define _NET_BATMAN_ADV_HASH_H_ |
| |
| #include "main.h" |
| |
| #include <linux/compiler.h> |
| #include <linux/list.h> |
| #include <linux/rculist.h> |
| #include <linux/spinlock.h> |
| #include <linux/stddef.h> |
| #include <linux/types.h> |
| |
| struct lock_class_key; |
| |
| /* callback to a compare function. should compare 2 element datas for their |
| * keys |
| * |
| * Return: true if same and false if not same |
| */ |
| typedef bool (*batadv_hashdata_compare_cb)(const struct hlist_node *, |
| const void *); |
| |
| /* the hashfunction |
| * |
| * Return: an index based on the key in the data of the first argument and the |
| * size the second |
| */ |
| typedef u32 (*batadv_hashdata_choose_cb)(const void *, u32); |
| 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 */ |
| u32 size; /* size of hashtable */ |
| }; |
| |
| /* allocates and clears the hash */ |
| struct batadv_hashtable *batadv_hash_new(u32 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 */ |
| u32 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 |
| * |
| * Return: 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) |
| { |
| u32 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. data could be the structure you use with |
| * just the key filled, we just need the key for comparing. |
| * |
| * Return: returns pointer do data on success, so you can remove the used |
| * structure yourself, or NULL on error |
| */ |
| static inline void *batadv_hash_remove(struct batadv_hashtable *hash, |
| batadv_hashdata_compare_cb compare, |
| batadv_hashdata_choose_cb choose, |
| void *data) |
| { |
| u32 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_ */ |