tipc: Hide internal details of node table implementation

[karo-tx-linux.git] / net / tipc / node.c

diff --git a/net/tipc/node.c b/net/tipc/node.c
index 153425997cced306df3a7a77699b7fa97c87a4fb..1790f503f57b693388983c96087af45e69fc7d55 100644 (file)
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -39,6 +39,8 @@
 #include "node.h"
 #include "name_distr.h"
 
+#define NODE_HTABLE_SIZE 512
+
 static void node_lost_contact(struct tipc_node *n_ptr);
 static void node_established_contact(struct tipc_node *n_ptr);
 
@@ -50,6 +52,17 @@ static u32 tipc_num_nodes;
 
 static atomic_t tipc_num_links = ATOMIC_INIT(0);
 
+/*
+ * A trivial power-of-two bitmask technique is used for speed, since this
+ * operation is done for every incoming TIPC packet. The number of hash table
+ * entries has been chosen so that no hash chain exceeds 8 nodes and will
+ * usually be much smaller (typically only a single node).
+ */
+static inline unsigned int tipc_hashfn(u32 addr)
+{
+       return addr & (NODE_HTABLE_SIZE - 1);
+}
+
 /*
  * tipc_node_find - locate specified node object, if it exists
  */