[deliverable/linux.git] / net / batman-adv / hash.h

/* 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: 0 if same and not 0 if not same
 */
typedef int (*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_ */
Commit	Line	Data
	1	/* Copyright (C) 2006-2016 B.A.T.M.A.N. contributors:
	2	*
	3	* Simon Wunderlich, Marek Lindner
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of version 2 of the GNU General Public
	7	* License as published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it will be useful, but
	10	* WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	12	* General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	16	*/
	17
	18	#ifndef _NET_BATMAN_ADV_HASH_H_
	19	#define _NET_BATMAN_ADV_HASH_H_
	20
	21	#include "main.h"
	22
	23	#include <linux/compiler.h>
	24	#include <linux/list.h>
	25	#include <linux/rculist.h>
	26	#include <linux/spinlock.h>
	27	#include <linux/stddef.h>
	28	#include <linux/types.h>
	29
	30	struct lock_class_key;
	31
	32	/* callback to a compare function. should compare 2 element datas for their
	33	* keys
	34	*
	35	* Return: 0 if same and not 0 if not same
	36	*/
	37	typedef int (batadv_hashdata_compare_cb)(const struct hlist_node ,
	38	const void *);
	39
	40	/* the hashfunction
	41	*
	42	* Return: an index based on the key in the data of the first argument and the
	43	* size the second
	44	*/
	45	typedef u32 (batadv_hashdata_choose_cb)(const void , u32);
	46	typedef void (batadv_hashdata_free_cb)(struct hlist_node , void *);
	47
	48	struct batadv_hashtable {
	49	struct hlist_head table; / the hashtable itself with the buckets */
	50	spinlock_t list_locks; / spinlock for each hash list entry */
	51	u32 size; /* size of hashtable */
	52	};
	53
	54	/* allocates and clears the hash */
	55	struct batadv_hashtable *batadv_hash_new(u32 size);
	56
	57	/* set class key for all locks */
	58	void batadv_hash_set_lock_class(struct batadv_hashtable *hash,
	59	struct lock_class_key *key);
	60
	61	/* free only the hashtable and the hash itself. */
	62	void batadv_hash_destroy(struct batadv_hashtable *hash);
	63
	64	/* remove the hash structure. if hashdata_free_cb != NULL, this function will be
	65	* called to remove the elements inside of the hash. if you don't remove the
	66	* elements, memory might be leaked.
	67	*/
	68	static inline void batadv_hash_delete(struct batadv_hashtable *hash,
	69	batadv_hashdata_free_cb free_cb,
	70	void *arg)
	71	{
	72	struct hlist_head *head;
	73	struct hlist_node node, node_tmp;
	74	spinlock_t list_lock; / spinlock to protect write access */
	75	u32 i;
	76
	77	for (i = 0; i < hash->size; i++) {
	78	head = &hash->table[i];
	79	list_lock = &hash->list_locks[i];
	80
	81	spin_lock_bh(list_lock);
	82	hlist_for_each_safe(node, node_tmp, head) {
	83	hlist_del_rcu(node);
	84
	85	if (free_cb)
	86	free_cb(node, arg);
	87	}
	88	spin_unlock_bh(list_lock);
	89	}
	90
	91	batadv_hash_destroy(hash);
	92	}
	93
	94	/**
	95	* batadv_hash_add - adds data to the hashtable
	96	* @hash: storage hash table
	97	* @compare: callback to determine if 2 hash elements are identical
	98	* @choose: callback calculating the hash index
	99	* @data: data passed to the aforementioned callbacks as argument
	100	* @data_node: to be added element
	101	*
	102	* Return: 0 on success, 1 if the element already is in the hash
	103	* and -1 on error.
	104	*/
	105	static inline int batadv_hash_add(struct batadv_hashtable *hash,
	106	batadv_hashdata_compare_cb compare,
	107	batadv_hashdata_choose_cb choose,
	108	const void *data,
	109	struct hlist_node *data_node)
	110	{
	111	u32 index;
	112	int ret = -1;
	113	struct hlist_head *head;
	114	struct hlist_node *node;
	115	spinlock_t list_lock; / spinlock to protect write access */
	116
	117	if (!hash)
	118	goto out;
	119
	120	index = choose(data, hash->size);
	121	head = &hash->table[index];
	122	list_lock = &hash->list_locks[index];
	123
	124	spin_lock_bh(list_lock);
	125
	126	hlist_for_each(node, head) {
	127	if (!compare(node, data))
	128	continue;
	129
	130	ret = 1;
	131	goto unlock;
	132	}
	133
	134	/* no duplicate found in list, add new element */
	135	hlist_add_head_rcu(data_node, head);
	136
	137	ret = 0;
	138
	139	unlock:
	140	spin_unlock_bh(list_lock);
	141	out:
	142	return ret;
	143	}
	144
	145	/* removes data from hash, if found. data could be the structure you use with
	146	* just the key filled, we just need the key for comparing.
	147	*
	148	* Return: returns pointer do data on success, so you can remove the used
	149	* structure yourself, or NULL on error
	150	*/
	151	static inline void batadv_hash_remove(struct batadv_hashtable hash,
	152	batadv_hashdata_compare_cb compare,
	153	batadv_hashdata_choose_cb choose,
	154	void *data)
	155	{
	156	u32 index;
	157	struct hlist_node *node;
	158	struct hlist_head *head;
	159	void *data_save = NULL;
	160
	161	index = choose(data, hash->size);
	162	head = &hash->table[index];
	163
	164	spin_lock_bh(&hash->list_locks[index]);
	165	hlist_for_each(node, head) {
	166	if (!compare(node, data))
	167	continue;
	168
	169	data_save = node;
	170	hlist_del_rcu(node);
	171	break;
	172	}
	173	spin_unlock_bh(&hash->list_locks[index]);
	174
	175	return data_save;
	176	}
	177
	178	#endif /* _NET_BATMAN_ADV_HASH_H_ */