fs: dlm: move out some hash functionality

This patch moves out some lowcomms hash functionality into lowcomms
header to provide them to other layers like midcomms as well.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/dlm/lowcomms.h b/fs/dlm/lowcomms.h
index a4384826442c..66dc1bb3de7f 100644
--- a/fs/dlm/lowcomms.h
+++ b/fs/dlm/lowcomms.h
@@ -13,6 +13,16 @@
 #define __LOWCOMMS_DOT_H__
 
 #define LOWCOMMS_MAX_TX_BUFFER_LEN	4096
+#define CONN_HASH_SIZE 32
+
+/* This is deliberately very simple because most clusters have simple
+ * sequential nodeids, so we should be able to go straight to a connection
+ * struct in the array
+ */
+static inline int nodeid_hash(int nodeid)
+{
+	return nodeid & (CONN_HASH_SIZE-1);
+}
 
 /* switch to check if dlm is running */
 extern int dlm_allow_conn;