summaryrefslogtreecommitdiff
path: root/net/tipc/ref.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/tipc/ref.c')
-rw-r--r--net/tipc/ref.c91
1 files changed, 87 insertions, 4 deletions
diff --git a/net/tipc/ref.c b/net/tipc/ref.c
index c38744c96ed1..d0b240e86ccd 100644
--- a/net/tipc/ref.c
+++ b/net/tipc/ref.c
@@ -2,7 +2,7 @@
* net/tipc/ref.c: TIPC object registry code
*
* Copyright (c) 1991-2006, Ericsson AB
- * Copyright (c) 2004-2005, Wind River Systems
+ * Copyright (c) 2004-2007, Wind River Systems
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -46,6 +46,37 @@
#include "node.h"
#include "bcast.h"
+/**
+ * struct reference - TIPC object reference entry
+ * @object: pointer to object associated with reference entry
+ * @lock: spinlock controlling access to object
+ * @data: reference value associated with object (or link to next unused entry)
+ */
+
+struct reference {
+ void *object;
+ spinlock_t lock;
+ union {
+ u32 next_plus_upper;
+ u32 reference;
+ } data;
+};
+
+/**
+ * struct tipc_ref_table - table of TIPC object reference entries
+ * @entries: pointer to array of reference entries
+ * @index_mask: bitmask for array index portion of reference values
+ * @first_free: array index of first unused object reference entry
+ * @last_free: array index of last unused object reference entry
+ */
+
+struct ref_table {
+ struct reference *entries;
+ u32 index_mask;
+ u32 first_free;
+ u32 last_free;
+};
+
/*
* Object reference table consists of 2**N entries.
*
@@ -61,7 +92,7 @@
* because entry 0's reference field has the form XXXX|1--1.
*/
-struct ref_table tipc_ref_table = { NULL };
+static struct ref_table tipc_ref_table = { NULL };
static DEFINE_RWLOCK(ref_table_lock);
@@ -198,8 +229,8 @@ void tipc_ref_discard(u32 ref)
tipc_ref_table.first_free = index;
else
/* next_plus_upper is always XXXX|0--0 for last free entry */
- tipc_ref_table.entries[tipc_ref_table.last_free].data.next_plus_upper
- |= index;
+ tipc_ref_table.entries[tipc_ref_table.last_free].
+ data.next_plus_upper |= index;
tipc_ref_table.last_free = index;
/* increment upper bits of entry to invalidate subsequent references */
@@ -208,3 +239,55 @@ exit:
write_unlock_bh(&ref_table_lock);
}
+/**
+ * tipc_ref_lock - lock referenced object and return pointer to it
+ */
+
+void *tipc_ref_lock(u32 ref)
+{
+ if (likely(tipc_ref_table.entries)) {
+ struct reference *r;
+
+ r = &tipc_ref_table.entries[ref & tipc_ref_table.index_mask];
+ spin_lock_bh(&r->lock);
+ if (likely(r->data.reference == ref))
+ return r->object;
+ spin_unlock_bh(&r->lock);
+ }
+ return NULL;
+}
+
+/**
+ * tipc_ref_unlock - unlock referenced object
+ */
+
+void tipc_ref_unlock(u32 ref)
+{
+ if (likely(tipc_ref_table.entries)) {
+ struct reference *r;
+
+ r = &tipc_ref_table.entries[ref & tipc_ref_table.index_mask];
+ if (likely(r->data.reference == ref))
+ spin_unlock_bh(&r->lock);
+ else
+ err("tipc_ref_unlock() invoked using "
+ "obsolete reference\n");
+ }
+}
+
+/**
+ * tipc_ref_deref - return pointer referenced object (without locking it)
+ */
+
+void *tipc_ref_deref(u32 ref)
+{
+ if (likely(tipc_ref_table.entries)) {
+ struct reference *r;
+
+ r = &tipc_ref_table.entries[ref & tipc_ref_table.index_mask];
+ if (likely(r->data.reference == ref))
+ return r->object;
+ }
+ return NULL;
+}
+