rdxtree: provide a lockless-aware slot load accessor

2 files changed, 13 insertions, 7 deletions

diff --git a/rdxtree.c b/rdxtree.c
index b93c345..1480a8e 100644
--- a/rdxtree.c
+++ b/rdxtree.c
@@ -76,13 +76,6 @@ typedef unsigned long long rdxtree_bm_t;
     ((~(rdxtree_bm_t)0) >> (RDXTREE_BM_SIZE - RDXTREE_RADIX_SIZE))
 
 /*
- * These macros can be replaced by actual functions in an environment
- * that provides lockless synchronization such as RCU.
- */
-#define llsync_assign_ptr(ptr, value)   ((ptr) = (value))
-#define llsync_read_ptr(ptr)            (ptr)
-
-/*
  * Radix tree node.
  *
  * The height of a tree is the number of nodes to traverse until stored
diff --git a/rdxtree.h b/rdxtree.h
index be0db3b..7604380 100644
--- a/rdxtree.h
+++ b/rdxtree.h
@@ -39,6 +39,13 @@
 #include <stdint.h>
 
 /*
+ * These macros can be replaced by actual functions in an environment
+ * that provides lockless synchronization such as RCU.
+ */
+#define llsync_assign_ptr(ptr, value)   ((ptr) = (value))
+#define llsync_read_ptr(ptr)            (ptr)
+
+/*
  * This macro selects between 32 or 64-bits (the default) keys.
  */
 #if 0
@@ -174,6 +181,12 @@ rdxtree_lookup_slot(const struct rdxtree *tree, rdxtree_key_t key)
     return rdxtree_lookup_common(tree, key, 1);
 }
 
+static inline void *
+rdxtree_load_slot(void **slot)
+{
+    return llsync_read_ptr(*slot);
+}
+
 /*
  * Replace a pointer in a tree.
  *