+ /*
+ * Perform a lookup query to handle the case where
+ * old_node_flag_ptr is NULL. We cannot use it to check if the
+ * node has been populated between RCU lookup and mutex
+ * acquisition.
+ */
+ if (!old_node_flag_ptr) {
+ uint8_t iter_key;
+ struct cds_ja_inode_flag *lookup_node_flag;
+ struct cds_ja_inode_flag **lookup_node_flag_ptr;
+
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (ja->tree_depth - level)));
+ lookup_node_flag = ja_node_get_nth(attach_node_flag,
+ &lookup_node_flag_ptr,
+ iter_key);
+ if (lookup_node_flag) {
+ ret = -EEXIST;
+ goto unlock_parent;
+ }
+ }
+