cregit-Linux how code gets into the kernel

Release 4.14 net/batman-adv/hash.h

Directory: net/batman-adv
/* 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
 * 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 <>.



#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; }


Sven Eckelmann8155.48%550.00%
Marek Lindner3826.03%220.00%
Antonio Quartulli1610.96%220.00%
Matthias Schiffer117.53%110.00%

/* 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; }


Sven Eckelmann8270.09%466.67%
Marek Lindner3529.91%233.33%

#endif /* _NET_BATMAN_ADV_HASH_H_ */

Overall Contributors

Sven Eckelmann29272.64%1168.75%
Marek Lindner8320.65%212.50%
Antonio Quartulli163.98%212.50%
Matthias Schiffer112.74%16.25%
Directory: net/batman-adv
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