From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 6 Jul 2011 15:19:08 +0000 (-0400)
Subject: rculfhash: add unique
X-Git-Tag: v0.7.0~43^2~223
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=3eca1b8cce5630bcbd865a8d30855c996bc021c3;p=userspace-rcu.git

rculfhash: add unique

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/rculfhash.c b/rculfhash.c
index 534a2f8..a5e4d9f 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -205,12 +205,13 @@ unsigned long _uatomic_max(unsigned long *ptr, unsigned long v)
 }
 
 static
-void _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node)
+int _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node,
+	     int unique)
 {
 	struct rcu_ht_node *iter_prev, *iter, *iter_prev_next, *next;
 
 	if (!t->size)
-		return;
+		return 0;
 	for (;;) {
 		uint32_t chain_len = 0;
 
@@ -232,6 +233,12 @@ void _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node)
 			next = rcu_dereference(clear_flag(iter)->next);
 			if (unlikely(is_removed(next)))
 				continue;
+			if (unique
+			    && !clear_flag(iter)->dummy
+			    && !ht->compare_fct(node->key, node->key_len,
+					clear_flag(iter)->key,
+					clear_flag(iter)->key_len))
+				return -EEXIST;
 			if (clear_flag(iter)->reverse_hash > node->reverse_hash)
 				break;
 			/* Only account for identical reverse hash once */
@@ -250,6 +257,7 @@ void _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node)
 		else
 			break;
 	}
+	return 0;
 }
 
 static
@@ -345,7 +353,7 @@ void init_table(struct rcu_ht *ht, struct rcu_table *t,
 		t->tbl[i]->dummy = 1;
 		t->tbl[i]->hash = i;
 		t->tbl[i]->reverse_hash = bit_reverse_ulong(i);
-		_ht_add(ht, t, t->tbl[i]);
+		(void) _ht_add(ht, t, t->tbl[i], 0);
 	}
 	t->resize_target = t->size = end;
 	t->resize_initiated = 0;
@@ -412,7 +420,18 @@ void ht_add(struct rcu_ht *ht, struct rcu_ht_node *node)
 	node->reverse_hash = bit_reverse_ulong((unsigned long) node->hash);
 
 	t = rcu_dereference(ht->t);
-	_ht_add(ht, t, node);
+	(void) _ht_add(ht, t, node, 0);
+}
+
+int ht_add_unique(struct rcu_ht *ht, struct rcu_ht_node *node)
+{
+	struct rcu_table *t;
+
+	node->hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
+	node->reverse_hash = bit_reverse_ulong((unsigned long) node->hash);
+
+	t = rcu_dereference(ht->t);
+	return _ht_add(ht, t, node, 1);
 }
 
 int ht_remove(struct rcu_ht *ht, struct rcu_ht_node *node)
diff --git a/tests/test_urcu_hash.c b/tests/test_urcu_hash.c
index 5935656..44b9531 100644
--- a/tests/test_urcu_hash.c
+++ b/tests/test_urcu_hash.c
@@ -405,9 +405,12 @@ void *thr_writer(void *_count)
 				(void *)(unsigned long)(rand_r(&rand_lookup) % RAND_POOL),
 				sizeof(void *),
 				(void *) 0x42);
-			ht_add(test_ht, node);
+			ret = ht_add_unique(test_ht, node);
 			rcu_read_unlock();
-			nr_add++;
+			if (ret)
+				nr_addexist++;
+			else
+				nr_add++;
 		} else {
 			/* May delete */
 			rcu_read_lock();
diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index 94206e3..ed75431 100644
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -55,6 +55,9 @@ struct rcu_ht_node *ht_lookup(struct rcu_ht *ht, void *key, size_t key_len);
 /* Call with rcu_read_lock held. */
 void ht_add(struct rcu_ht *ht, struct rcu_ht_node *node);
 
+/* Call with rcu_read_lock held. */
+int ht_add_unique(struct rcu_ht *ht, struct rcu_ht_node *node);
+
 /* Call with rcu_read_lock held. */
 int ht_remove(struct rcu_ht *ht, struct rcu_ht_node *node);