1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (C) 2006-2020 B.A.T.M.A.N. contributors:
4 * Simon Wunderlich, Marek Lindner
7 #ifndef _NET_BATMAN_ADV_HASH_H_
8 #define _NET_BATMAN_ADV_HASH_H_
12 #include <linux/atomic.h>
13 #include <linux/compiler.h>
14 #include <linux/list.h>
15 #include <linux/lockdep.h>
16 #include <linux/rculist.h>
17 #include <linux/spinlock.h>
18 #include <linux/stddef.h>
19 #include <linux/types.h>
21 /* callback to a compare function. should compare 2 element datas for their
24 * Return: true if same and false if not same
26 typedef bool (*batadv_hashdata_compare_cb
)(const struct hlist_node
*,
31 * Return: an index based on the key in the data of the first argument and the
34 typedef u32 (*batadv_hashdata_choose_cb
)(const void *, u32
);
35 typedef void (*batadv_hashdata_free_cb
)(struct hlist_node
*, void *);
38 * struct batadv_hashtable - Wrapper of simple hlist based hashtable
40 struct batadv_hashtable
{
41 /** @table: the hashtable itself with the buckets */
42 struct hlist_head
*table
;
44 /** @list_locks: spinlock for each hash list entry */
45 spinlock_t
*list_locks
;
47 /** @size: size of hashtable */
50 /** @generation: current (generation) sequence number */
54 /* allocates and clears the hash */
55 struct batadv_hashtable
*batadv_hash_new(u32 size
);
57 /* set class key for all locks */
58 void batadv_hash_set_lock_class(struct batadv_hashtable
*hash
,
59 struct lock_class_key
*key
);
61 /* free only the hashtable and the hash itself. */
62 void batadv_hash_destroy(struct batadv_hashtable
*hash
);
65 * batadv_hash_add() - adds data to the hashtable
66 * @hash: storage hash table
67 * @compare: callback to determine if 2 hash elements are identical
68 * @choose: callback calculating the hash index
69 * @data: data passed to the aforementioned callbacks as argument
70 * @data_node: to be added element
72 * Return: 0 on success, 1 if the element already is in the hash
75 static inline int batadv_hash_add(struct batadv_hashtable
*hash
,
76 batadv_hashdata_compare_cb compare
,
77 batadv_hashdata_choose_cb choose
,
79 struct hlist_node
*data_node
)
83 struct hlist_head
*head
;
84 struct hlist_node
*node
;
85 spinlock_t
*list_lock
; /* spinlock to protect write access */
90 index
= choose(data
, hash
->size
);
91 head
= &hash
->table
[index
];
92 list_lock
= &hash
->list_locks
[index
];
94 spin_lock_bh(list_lock
);
96 hlist_for_each(node
, head
) {
97 if (!compare(node
, data
))
104 /* no duplicate found in list, add new element */
105 hlist_add_head_rcu(data_node
, head
);
106 atomic_inc(&hash
->generation
);
111 spin_unlock_bh(list_lock
);
117 * batadv_hash_remove() - Removes data from hash, if found
119 * @compare: callback to determine if 2 hash elements are identical
120 * @choose: callback calculating the hash index
121 * @data: data passed to the aforementioned callbacks as argument
123 * ata could be the structure you use with just the key filled, we just need
124 * the key for comparing.
126 * Return: returns pointer do data on success, so you can remove the used
127 * structure yourself, or NULL on error
129 static inline void *batadv_hash_remove(struct batadv_hashtable
*hash
,
130 batadv_hashdata_compare_cb compare
,
131 batadv_hashdata_choose_cb choose
,
135 struct hlist_node
*node
;
136 struct hlist_head
*head
;
137 void *data_save
= NULL
;
139 index
= choose(data
, hash
->size
);
140 head
= &hash
->table
[index
];
142 spin_lock_bh(&hash
->list_locks
[index
]);
143 hlist_for_each(node
, head
) {
144 if (!compare(node
, data
))
149 atomic_inc(&hash
->generation
);
152 spin_unlock_bh(&hash
->list_locks
[index
]);
157 #endif /* _NET_BATMAN_ADV_HASH_H_ */