1 files changed, 112 insertions, 101 deletions

diff --git a/net/batman-adv/hash.h b/net/batman-adv/hash.h
index 09216ade16f..539fc126679 100644
--- a/net/batman-adv/hash.h
+++ b/net/batman-adv/hash.h
@@ -1,5 +1,4 @@
-/*
- * Copyright (C) 2006-2010 B.A.T.M.A.N. contributors:
+/* Copyright (C) 2006-2014 B.A.T.M.A.N. contributors:
  *
  * Simon Wunderlich, Marek Lindner
  *
@@ -13,10 +12,7 @@
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA
- *
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef _NET_BATMAN_ADV_HASH_H_
@@ -24,153 +20,168 @@
 
 #include <linux/list.h>
 
-/* 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 (*hashdata_compare_cb)(void *, void *);
+/* 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, should return an index
  * based on the key in the data of the first
- * argument and the size the second */
-typedef int (*hashdata_choose_cb)(void *, int);
-typedef void (*hashdata_free_cb)(void *, void *);
-
-struct element_t {
-	void *data;		/* pointer to the data */
-	struct hlist_node hlist;	/* bucket list pointer */
-};
+ * argument and the size the second
+ */
+typedef uint32_t (*batadv_hashdata_choose_cb)(const void *, uint32_t);
+typedef void (*batadv_hashdata_free_cb)(struct hlist_node *, void *);
 
-struct hashtable_t {
-	struct hlist_head *table;   /* the hashtable itself, with the buckets */
-	int size;		    /* size of hashtable */
+struct batadv_hashtable {
+	struct hlist_head *table;   /* the hashtable itself with the buckets */
+	spinlock_t *list_locks;     /* spinlock for each hash list entry */
+	uint32_t size;		    /* size of hashtable */
 };
 
 /* allocates and clears the hash */
-struct hashtable_t *hash_new(int size);
+struct batadv_hashtable *batadv_hash_new(uint32_t size);
 
-/* remove element if you already found the element you want to delete and don't
- * need the overhead to find it again with hash_remove().  But usually, you
- * don't want to use this function, as it fiddles with hash-internals. */
-void *hash_remove_element(struct hashtable_t *hash, struct element_t *elem);
+/* 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 hash_destroy(struct hashtable_t *hash);
+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 hash_delete(struct hashtable_t *hash,
-			       hashdata_free_cb free_cb, void *arg)
+ * 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 *walk, *safe;
-	struct element_t *bucket;
-	int i;
+	struct hlist_node *node, *node_tmp;
+	spinlock_t *list_lock; /* spinlock to protect write access */
+	uint32_t i;
 
 	for (i = 0; i < hash->size; i++) {
 		head = &hash->table[i];
+		list_lock = &hash->list_locks[i];
 
-		hlist_for_each_safe(walk, safe, head) {
-			bucket = hlist_entry(walk, struct element_t, hlist);
-			if (free_cb)
-				free_cb(bucket->data, arg);
+		spin_lock_bh(list_lock);
+		hlist_for_each_safe(node, node_tmp, head) {
+			hlist_del_rcu(node);
 
-			hlist_del(walk);
-			kfree(bucket);
+			if (free_cb)
+				free_cb(node, arg);
 		}
+		spin_unlock_bh(list_lock);
 	}
 
-	hash_destroy(hash);
+	batadv_hash_destroy(hash);
+}
+
+/**
+ *	batadv_hash_bytes - hash some bytes and add them to the previous hash
+ *	@hash: previous hash value
+ *	@data: data to be hashed
+ *	@size: number of bytes to be hashed
+ *
+ *	Returns the new hash value.
+ */
+static inline uint32_t batadv_hash_bytes(uint32_t hash, const void *data,
+					 uint32_t size)
+{
+	const unsigned char *key = data;
+	int i;
+
+	for (i = 0; i < size; i++) {
+		hash += key[i];
+		hash += (hash << 10);
+		hash ^= (hash >> 6);
+	}
+	return hash;
 }
 
-/* adds data to the hashtable. returns 0 on success, -1 on error */
-static inline int hash_add(struct hashtable_t *hash,
-			   hashdata_compare_cb compare,
-			   hashdata_choose_cb choose, void *data)
+/**
+ *	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
+ *
+ *	Returns 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)
 {
-	int index;
+	uint32_t index;
+	int ret = -1;
 	struct hlist_head *head;
-	struct hlist_node *walk, *safe;
-	struct element_t *bucket;
+	struct hlist_node *node;
+	spinlock_t *list_lock; /* spinlock to protect write access */
 
 	if (!hash)
-		return -1;
+		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_safe(walk, safe, head) {
-		bucket = hlist_entry(walk, struct element_t, hlist);
-		if (compare(bucket->data, data))
-			return -1;
+	hlist_for_each(node, head) {
+		if (!compare(node, data))
+			continue;
+
+		ret = 1;
+		goto unlock;
 	}
 
 	/* no duplicate found in list, add new element */
-	bucket = kmalloc(sizeof(struct element_t), GFP_ATOMIC);
-
-	if (!bucket)
-		return -1;
+	hlist_add_head_rcu(data_node, head);
 
-	bucket->data = data;
-	hlist_add_head(&bucket->hlist, head);
+	ret = 0;
 
-	return 0;
+unlock:
+	spin_unlock_bh(list_lock);
+out:
+	return ret;
 }
 
 /* removes data from hash, if found. returns pointer do data on success, so you
  * can remove the used structure yourself, or NULL on error .  data could be the
  * structure you use with just the key filled, we just need the key for
- * comparing. */
-static inline void *hash_remove(struct hashtable_t *hash,
-				hashdata_compare_cb compare,
-				hashdata_choose_cb choose, void *data)
+ * comparing.
+ */
+static inline void *batadv_hash_remove(struct batadv_hashtable *hash,
+				       batadv_hashdata_compare_cb compare,
+				       batadv_hashdata_choose_cb choose,
+				       void *data)
 {
-	size_t index;
-	struct hlist_node *walk;
-	struct element_t *bucket;
+	uint32_t index;
+	struct hlist_node *node;
 	struct hlist_head *head;
-	void *data_save;
+	void *data_save = NULL;
 
 	index = choose(data, hash->size);
 	head = &hash->table[index];
 
-	hlist_for_each_entry(bucket, walk, head, hlist) {
-		if (compare(bucket->data, data)) {
-			data_save = bucket->data;
-			hlist_del(walk);
-			kfree(bucket);
-			return data_save;
-		}
-	}
-
-	return NULL;
-}
-
-/* finds data, based on the key in keydata. returns the found data on success,
- * or NULL on error */
-static inline void *hash_find(struct hashtable_t *hash,
-			      hashdata_compare_cb compare,
-			      hashdata_choose_cb choose, void *keydata)
-{
-	int index;
-	struct hlist_head *head;
-	struct hlist_node *walk;
-	struct element_t *bucket;
-
-	if (!hash)
-		return NULL;
-
-	index = choose(keydata , hash->size);
-	head = &hash->table[index];
+	spin_lock_bh(&hash->list_locks[index]);
+	hlist_for_each(node, head) {
+		if (!compare(node, data))
+			continue;
 
-	hlist_for_each(walk, head) {
-		bucket = hlist_entry(walk, struct element_t, hlist);
-		if (compare(bucket->data, keydata))
-			return bucket->data;
+		data_save = node;
+		hlist_del_rcu(node);
+		break;
 	}
+	spin_unlock_bh(&hash->list_locks[index]);
 
-	return NULL;
+	return data_save;
 }
 
 #endif /* _NET_BATMAN_ADV_HASH_H_ */