Release 4.15 net/batman-adv/hash.h

/* Copyright (C) 2006-2017  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);

/**
 *      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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Sven Eckelmann
81
55.48%
5
50.00%
Marek Lindner
38
26.03%
2
20.00%
Antonio Quartulli
16
10.96%
2
20.00%
Matthias Schiffer
11
7.53%
1
10.00%
Total
146
100.00%
10
100.00%

/* 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Sven Eckelmann
82
70.09%
4
66.67%
Marek Lindner
35
29.91%
2
33.33%
Total
117
100.00%
6
100.00%

#endif /* _NET_BATMAN_ADV_HASH_H_ */
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Sven Eckelmann
292
72.64%
11
68.75%
Marek Lindner
83
20.65%
2
12.50%
Antonio Quartulli
16
3.98%
2
12.50%
Matthias Schiffer
11
2.74%
1
6.25%
Total
402
100.00%
16
100.00%
Directory: net/batman-adv

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.