Rename the parameter name of _cds_lfht_replace()

[urcu.git] / rculfhash.c

diff --git a/rculfhash.c b/rculfhash.c
index c7b9ea895cf6594d11a9ef8a56a461ba3bc2ae7d..be995dfeaf5ef70795a6fd74a7bc34f4ced558c6 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -724,7 +724,12 @@ struct _cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
 
        assert(size > 0);
        index = hash & (size - 1);
-       order = get_count_order_ulong(index + 1);
+       /*
+        * equivalent to get_count_order_ulong(index + 1), but optimizes
+        * away the non-existing 0 special-case for
+        * get_count_order_ulong.
+        */
+       order = fls_ulong(index);
 
        dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n",
                   hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1)));
@@ -782,10 +787,10 @@ void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node
 static
 int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
                struct cds_lfht_node *old_node,
-               struct cds_lfht_node *ret_next,
+               struct cds_lfht_node *old_next,
                struct cds_lfht_node *new_node)
 {
-       struct cds_lfht_node *dummy, *old_next;
+       struct cds_lfht_node *dummy, *ret_next;
        struct _cds_lfht_node *lookup;
        int flagged = 0;
 
@@ -797,9 +802,8 @@ int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
        assert(!is_removed(new_node));
        assert(!is_dummy(new_node));
        assert(new_node != old_node);
-       do {
+       for (;;) {
                /* Insert after node to be replaced */
-               old_next = ret_next;
                if (is_removed(old_next)) {
                        /*
                         * Too late, the old node has been removed under us
@@ -822,7 +826,10 @@ int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
                 */
                ret_next = uatomic_cmpxchg(&old_node->p.next,
                              old_next, flag_removed(new_node));
-       } while (ret_next != old_next);
+               if (ret_next == old_next)
+                       break;
+               old_next = ret_next;
+       }
 
        /* We performed the replacement. */
        flagged = 1;
@@ -855,7 +862,7 @@ struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
                                enum add_mode mode, int dummy)
 {
        struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next,
-                       *dummy_node, *return_node;
+                       *return_node;
        struct _cds_lfht_node *lookup;
 
        assert(!is_dummy(node));
@@ -882,11 +889,15 @@ struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
                                goto insert;
                        if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash))
                                goto insert;
+                       /* dummy node is the first node of the identical-hash-value chain */
+                       if (dummy && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash)
+                               goto insert;
                        next = rcu_dereference(clear_flag(iter)->p.next);
                        if (unlikely(is_removed(next)))
                                goto gc_node;
                        if ((mode == ADD_UNIQUE || mode == ADD_REPLACE)
                            && !is_dummy(next)
+                           && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash
                            && !ht->compare_fct(node->key, node->key_len,
                                                clear_flag(iter)->key,
                                                clear_flag(iter)->key_len)) {
@@ -924,7 +935,7 @@ struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
                                return_node = NULL;
                        else    /* ADD_DEFAULT and ADD_UNIQUE */
                                return_node = node;
-                       goto gc_end;
+                       goto end;
                }
 
        replace:
@@ -946,10 +957,6 @@ struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
                (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next);
                /* retry */
        }
-gc_end:
-       /* Garbage collect logically removed nodes in the bucket */
-       dummy_node = (struct cds_lfht_node *) lookup;
-       _cds_lfht_gc_bucket(dummy_node, node);
 end:
        return return_node;
 }
@@ -1340,6 +1347,7 @@ void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len,
                next = rcu_dereference(node->p.next);
                if (likely(!is_removed(next))
                    && !is_dummy(next)
+                   && clear_flag(node)->p.reverse_hash == reverse_hash
                    && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
                                break;
                }