1 files changed, 46 insertions, 73 deletions

diff --git a/net/batman-adv/hash.h b/net/batman-adv/hash.h
index 09216ade16f1..434822b27473 100644
--- a/net/batman-adv/hash.h
+++ b/net/batman-adv/hash.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2010 B.A.T.M.A.N. contributors:
+ * Copyright (C) 2006-2011 B.A.T.M.A.N. contributors:
  *
  * Simon Wunderlich, Marek Lindner
  *
@@ -28,32 +28,23 @@
  * compare 2 element datas for their keys,
  * return 0 if same and not 0 if not
  * same */
-typedef int (*hashdata_compare_cb)(void *, void *);
+typedef int (*hashdata_compare_cb)(struct hlist_node *, 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 */
-};
+typedef void (*hashdata_free_cb)(struct hlist_node *, void *);
 
 struct hashtable_t {
-	struct hlist_head *table;   /* the hashtable itself, with the buckets */
+	struct hlist_head *table;   /* the hashtable itself with the buckets */
+	spinlock_t *list_locks;     /* spinlock for each hash list entry */
 	int size;		    /* size of hashtable */
 };
 
 /* allocates and clears the hash */
 struct hashtable_t *hash_new(int 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);
-
 /* free only the hashtable and the hash itself. */
 void hash_destroy(struct hashtable_t *hash);
 
@@ -64,21 +55,22 @@ static inline void hash_delete(struct hashtable_t *hash,
 			       hashdata_free_cb free_cb, void *arg)
 {
 	struct hlist_head *head;
-	struct hlist_node *walk, *safe;
-	struct element_t *bucket;
+	struct hlist_node *node, *node_tmp;
+	spinlock_t *list_lock; /* spinlock to protect write access */
 	int 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);
@@ -87,35 +79,41 @@ static inline void hash_delete(struct hashtable_t *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)
+			   hashdata_choose_cb choose,
+			   void *data, struct hlist_node *data_node)
 {
 	int index;
 	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 err;
 
 	index = choose(data, hash->size);
 	head = &hash->table[index];
+	list_lock = &hash->list_locks[index];
+
+	rcu_read_lock();
+	__hlist_for_each_rcu(node, head) {
+		if (!compare(node, data))
+			continue;
 
-	hlist_for_each_safe(walk, safe, head) {
-		bucket = hlist_entry(walk, struct element_t, hlist);
-		if (compare(bucket->data, data))
-			return -1;
+		goto err_unlock;
 	}
+	rcu_read_unlock();
 
 	/* no duplicate found in list, add new element */
-	bucket = kmalloc(sizeof(struct element_t), GFP_ATOMIC);
-
-	if (!bucket)
-		return -1;
-
-	bucket->data = data;
-	hlist_add_head(&bucket->hlist, head);
+	spin_lock_bh(list_lock);
+	hlist_add_head_rcu(data_node, head);
+	spin_unlock_bh(list_lock);
 
 	return 0;
+
+err_unlock:
+	rcu_read_unlock();
+err:
+	return -1;
 }
 
 /* removes data from hash, if found. returns pointer do data on success, so you
@@ -127,50 +125,25 @@ static inline void *hash_remove(struct hashtable_t *hash,
 				hashdata_choose_cb choose, void *data)
 {
 	size_t index;
-	struct hlist_node *walk;
-	struct element_t *bucket;
+	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_ */