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157 lines
3.9 KiB
157 lines
3.9 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* Copyright (C) B.A.T.M.A.N. contributors: |
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* |
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* Simon Wunderlich, Marek Lindner |
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*/ |
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#ifndef _NET_BATMAN_ADV_HASH_H_ |
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#define _NET_BATMAN_ADV_HASH_H_ |
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#include "main.h" |
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#include <linux/atomic.h> |
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#include <linux/compiler.h> |
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#include <linux/list.h> |
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#include <linux/lockdep.h> |
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#include <linux/rculist.h> |
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#include <linux/spinlock.h> |
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#include <linux/stddef.h> |
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#include <linux/types.h> |
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/* callback to a compare function. should compare 2 element data for their |
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* keys |
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* |
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* Return: true if same and false if not same |
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*/ |
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typedef bool (*batadv_hashdata_compare_cb)(const struct hlist_node *, |
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const void *); |
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/* the hashfunction |
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* |
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* Return: an index based on the key in the data of the first argument and the |
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* size the second |
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*/ |
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typedef u32 (*batadv_hashdata_choose_cb)(const void *, u32); |
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typedef void (*batadv_hashdata_free_cb)(struct hlist_node *, void *); |
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/** |
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* struct batadv_hashtable - Wrapper of simple hlist based hashtable |
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*/ |
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struct batadv_hashtable { |
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/** @table: the hashtable itself with the buckets */ |
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struct hlist_head *table; |
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/** @list_locks: spinlock for each hash list entry */ |
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spinlock_t *list_locks; |
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/** @size: size of hashtable */ |
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u32 size; |
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/** @generation: current (generation) sequence number */ |
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atomic_t generation; |
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}; |
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/* allocates and clears the hash */ |
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struct batadv_hashtable *batadv_hash_new(u32 size); |
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/* set class key for all locks */ |
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void batadv_hash_set_lock_class(struct batadv_hashtable *hash, |
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struct lock_class_key *key); |
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/* free only the hashtable and the hash itself. */ |
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void batadv_hash_destroy(struct batadv_hashtable *hash); |
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/** |
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* batadv_hash_add() - adds data to the hashtable |
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* @hash: storage hash table |
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* @compare: callback to determine if 2 hash elements are identical |
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* @choose: callback calculating the hash index |
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* @data: data passed to the aforementioned callbacks as argument |
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* @data_node: to be added element |
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* |
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* Return: 0 on success, 1 if the element already is in the hash |
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* and -1 on error. |
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*/ |
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static inline int batadv_hash_add(struct batadv_hashtable *hash, |
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batadv_hashdata_compare_cb compare, |
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batadv_hashdata_choose_cb choose, |
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const void *data, |
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struct hlist_node *data_node) |
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{ |
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u32 index; |
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int ret = -1; |
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struct hlist_head *head; |
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struct hlist_node *node; |
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spinlock_t *list_lock; /* spinlock to protect write access */ |
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if (!hash) |
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goto out; |
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index = choose(data, hash->size); |
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head = &hash->table[index]; |
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list_lock = &hash->list_locks[index]; |
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spin_lock_bh(list_lock); |
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hlist_for_each(node, head) { |
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if (!compare(node, data)) |
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continue; |
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ret = 1; |
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goto unlock; |
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} |
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/* no duplicate found in list, add new element */ |
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hlist_add_head_rcu(data_node, head); |
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atomic_inc(&hash->generation); |
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ret = 0; |
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unlock: |
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spin_unlock_bh(list_lock); |
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out: |
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return ret; |
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} |
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/** |
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* batadv_hash_remove() - Removes data from hash, if found |
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* @hash: hash table |
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* @compare: callback to determine if 2 hash elements are identical |
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* @choose: callback calculating the hash index |
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* @data: data passed to the aforementioned callbacks as argument |
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* |
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* ata could be the structure you use with just the key filled, we just need |
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* the key for comparing. |
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* |
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* Return: returns pointer do data on success, so you can remove the used |
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* structure yourself, or NULL on error |
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*/ |
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static inline void *batadv_hash_remove(struct batadv_hashtable *hash, |
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batadv_hashdata_compare_cb compare, |
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batadv_hashdata_choose_cb choose, |
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void *data) |
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{ |
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u32 index; |
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struct hlist_node *node; |
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struct hlist_head *head; |
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void *data_save = NULL; |
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index = choose(data, hash->size); |
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head = &hash->table[index]; |
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spin_lock_bh(&hash->list_locks[index]); |
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hlist_for_each(node, head) { |
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if (!compare(node, data)) |
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continue; |
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data_save = node; |
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hlist_del_rcu(node); |
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atomic_inc(&hash->generation); |
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break; |
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} |
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spin_unlock_bh(&hash->list_locks[index]); |
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return data_save; |
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} |
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#endif /* _NET_BATMAN_ADV_HASH_H_ */
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