rculfhash: update add_unique api

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

diff --git a/rculfhash.c b/rculfhash.c
index 1ccd3f15a5b8be89b8ca4fce5b34f1e588e9473e..556ec36ddab261625d3c3b412496718c790d0c0b 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -234,14 +234,16 @@ void _ht_gc_bucket(struct rcu_ht_node *dummy, struct rcu_ht_node *node)
 }
 
 static
-int _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node,
-            int unique)
+struct rcu_ht_node *_ht_add(struct rcu_ht *ht, struct rcu_table *t,
+                           struct rcu_ht_node *node, int unique)
 {
        struct rcu_ht_node *iter_prev, *dummy, *iter, *next;
        unsigned long hash;
 
-       if (!t->size)
-               return 0;
+       if (!t->size) {
+               assert(node->dummy);
+               return node;    /* Initial first add (head) */
+       }
        hash = bit_reverse_ulong(node->reverse_hash);
        for (;;) {
                uint32_t chain_len = 0;
@@ -267,7 +269,7 @@ int _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node,
                            && !ht->compare_fct(node->key, node->key_len,
                                                clear_flag(iter)->key,
                                                clear_flag(iter)->key_len))
-                               return -EEXIST;
+                               return clear_flag(iter);
                        /* Only account for identical reverse hash once */
                        if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash)
                                check_resize(ht, t, ++chain_len);
@@ -293,7 +295,7 @@ gc_end:
        /* Garbage collect logically removed nodes in the bucket */
        dummy = rcu_dereference(t->tbl[hash & (t->size - 1)]);
        _ht_gc_bucket(dummy, node);
-       return 0;
+       return node;
 }
 
 static
@@ -423,7 +425,7 @@ void ht_add(struct rcu_ht *ht, struct rcu_ht_node *node)
        (void) _ht_add(ht, t, node, 0);
 }
 
-int ht_add_unique(struct rcu_ht *ht, struct rcu_ht_node *node)
+struct rcu_ht_node *ht_add_unique(struct rcu_ht *ht, struct rcu_ht_node *node)
 {
        struct rcu_table *t;
        unsigned long hash;

diff --git a/tests/test_urcu_hash.c b/tests/test_urcu_hash.c
index e8c51d86acaa4043391b91f1262755c654d28682..16374d93ee5903876b03da344df97e302769959c 100644 (file)
--- a/tests/test_urcu_hash.c
+++ b/tests/test_urcu_hash.c
@@ -387,7 +387,7 @@ void free_node_cb(struct rcu_head *head)
 
 void *thr_writer(void *_count)
 {
-       struct rcu_ht_node *node;
+       struct rcu_ht_node *node, *ret_node;
        struct wr_count *count = _count;
        int ret;
 
@@ -410,9 +410,9 @@ void *thr_writer(void *_count)
                        ht_node_init(node,
                                (void *)(unsigned long)(rand_r(&rand_lookup) % RAND_POOL),
                                sizeof(void *));
-                       ret = ht_add_unique(test_ht, node);
+                       ret_node = ht_add_unique(test_ht, node);
                        rcu_read_unlock();
-                       if (ret) {
+                       if (ret_node != node) {
                                free(node);
                                nr_addexist++;
                        } else
@@ -569,6 +569,7 @@ int main(int argc, char **argv)
        count_writer = malloc(sizeof(*count_writer) * nr_writers);
        test_ht = ht_new(test_hash, test_compare, 0x42UL,
                         HASH_SIZE, call_rcu);
+
        next_aff = 0;
 
        for (i = 0; i < nr_readers; i++) {

diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index bec7776c2fd6f3f2f2eb58c9c058dafd18e2d3f0..6bb1ccf619b381e59f0f8d5098b643e569626233 100644 (file)
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -58,8 +58,13 @@ 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.
+ * Returns the node added upon success.
+ * Returns the unique node already present upon failure. If ht_add_unique fails,
+ * the node passed as parameter should be freed by the caller.
+ */
+struct rcu_ht_node *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);