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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 | /* SPDX-License-Identifier: GPL-2.0 */ /* Copyright (C) B.A.T.M.A.N. contributors: * * Simon Wunderlich, Marek Lindner */ #ifndef _NET_BATMAN_ADV_HASH_H_ #define _NET_BATMAN_ADV_HASH_H_ #include "main.h" #include <linux/atomic.h> #include <linux/compiler.h> #include <linux/list.h> #include <linux/lockdep.h> #include <linux/rculist.h> #include <linux/spinlock.h> #include <linux/stddef.h> #include <linux/types.h> /* callback to a compare function. should compare 2 element data 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 - Wrapper of simple hlist based hashtable */ struct batadv_hashtable { /** @table: the hashtable itself with the buckets */ struct hlist_head *table; /** @list_locks: spinlock for each hash list entry */ spinlock_t *list_locks; /** @size: size of hashtable */ u32 size; /** @generation: current (generation) sequence number */ atomic_t generation; }; /* 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); /** * 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); atomic_inc(&hash->generation); ret = 0; unlock: spin_unlock_bh(list_lock); out: return ret; } /** * batadv_hash_remove() - Removes data from hash, if found * @hash: 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 * * ata 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); atomic_inc(&hash->generation); break; } spin_unlock_bh(&hash->list_locks[index]); return data_save; } #endif /* _NET_BATMAN_ADV_HASH_H_ */ |