rcuja: API change: move rcu_head to user code

[userspace-rcu.git] / rcuja / rcuja.c

diff --git a/rcuja/rcuja.c b/rcuja/rcuja.c
index 74bb3910a384b67cc410ff09a12c953447b3cded..4d1f2b435a1433c44cdc3a8ae0983178000e0160 100644 (file)
--- a/rcuja/rcuja.c
+++ b/rcuja/rcuja.c
@@ -1802,8 +1802,9 @@ struct cds_hlist_head cds_ja_lookup_lower_equal(struct cds_ja *ja, uint64_t key)
 
        /*
         * From this point, we are guaranteed to be able to find a
-        * "lower than" match. ja_detach_node() guarantees that it is
-        * not possible for a lookup to reach a dead-end.
+        * "lower than" match. ja_attach_node() and ja_detach_node()
+        * both guarantee that it is not possible for a lookup to reach
+        * a dead-end.
         */
 
        /* Find rightmost child of rightmost child (recursively). */
@@ -1831,6 +1832,12 @@ struct cds_hlist_head cds_ja_lookup_lower_equal(struct cds_ja *ja, uint64_t key)
  * parent lock (if needed).  Then we can proceed to create the new
  * branch. Publish the new branch, and release locks.
  * TODO: we currently always take the parent lock even when not needed.
+ *
+ * ja_attach_node() ensures that a lookup will _never_ see a branch that
+ * leads to a dead-end: before attaching a branch, the entire content of
+ * the new branch is populated, thus creating a cluster, before
+ * attaching the cluster to the rest of the tree, thus making it visible
+ * to lookups.
  */
 static
 int ja_attach_node(struct cds_ja *ja,
@@ -2522,14 +2529,12 @@ ja_error:
 __attribute__((visibility("protected")))
 void rcuja_free_all_children(struct cds_ja_shadow_node *shadow_node,
                struct cds_ja_inode_flag *node_flag,
-               void (*free_node_cb)(struct rcu_head *head))
+               void (*rcu_free_node)(struct cds_ja_node *node))
 {
-       const struct rcu_flavor_struct *flavor;
        unsigned int type_index;
        struct cds_ja_inode *node;
        const struct cds_ja_type *type;
 
-       flavor = cds_lfht_rcu_flavor(shadow_node->ja->ht);
        node = ja_node_ptr(node_flag);
        assert(node != NULL);
        type_index = ja_node_type(node_flag);
@@ -2554,7 +2559,7 @@ void rcuja_free_all_children(struct cds_ja_shadow_node *shadow_node,
                                continue;
                        head.next = (struct cds_hlist_node *) iter;
                        cds_hlist_for_each_entry_safe(entry, pos, tmp, &head, list) {
-                               flavor->update_call_rcu(&entry->head, free_node_cb);
+                               rcu_free_node(entry);
                        }
                }
                break;
@@ -2582,7 +2587,7 @@ void rcuja_free_all_children(struct cds_ja_shadow_node *shadow_node,
                                        continue;
                                head.next = (struct cds_hlist_node *) iter;
                                cds_hlist_for_each_entry_safe(entry, pos, tmp, &head, list) {
-                                       flavor->update_call_rcu(&entry->head, free_node_cb);
+                                       rcu_free_node(entry);
                                }
                        }
                }
@@ -2605,7 +2610,7 @@ void rcuja_free_all_children(struct cds_ja_shadow_node *shadow_node,
                                continue;
                        head.next = (struct cds_hlist_node *) iter;
                        cds_hlist_for_each_entry_safe(entry, pos, tmp, &head, list) {
-                               flavor->update_call_rcu(&entry->head, free_node_cb);
+                               rcu_free_node(entry);
                        }
                }
                break;
@@ -2664,7 +2669,7 @@ int ja_final_checks(struct cds_ja *ja)
  * being destroyed (ensured by the caller).
  */
 int cds_ja_destroy(struct cds_ja *ja,
-               void (*free_node_cb)(struct rcu_head *head))
+               void (*rcu_free_node)(struct cds_ja_node *node))
 {
        const struct rcu_flavor_struct *flavor;
        int ret;
@@ -2672,7 +2677,7 @@ int cds_ja_destroy(struct cds_ja *ja,
        flavor = cds_lfht_rcu_flavor(ja->ht);
        rcuja_shadow_prune(ja->ht,
                RCUJA_SHADOW_CLEAR_FREE_NODE | RCUJA_SHADOW_CLEAR_FREE_LOCK,
-               free_node_cb);
+               rcu_free_node);
        flavor->thread_offline();
        ret = rcuja_delete_ht(ja->ht);
        if (ret)