From b97bf3fd8f6a16966d4f18983b2c40993ff937d4 Mon Sep 17 00:00:00 2001
From: Per Liden <per.liden@nospam.ericsson.com>
Date: Mon, 2 Jan 2006 19:04:38 +0100
Subject: [TIPC] Initial merge

TIPC (Transparent Inter Process Communication) is a protocol designed for
intra cluster communication. For more information see
http://tipc.sourceforge.net

Signed-off-by: Per Liden <per.liden@nospam.ericsson.com>
---
 net/tipc/ref.h | 128 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 net/tipc/ref.h

(limited to 'net/tipc/ref.h')

diff --git a/net/tipc/ref.h b/net/tipc/ref.h
new file mode 100644
index 00000000000..e6cd5bb3dc2
--- /dev/null
+++ b/net/tipc/ref.h
@@ -0,0 +1,128 @@
+/*
+ * net/tipc/ref.h: Include file for TIPC object registry code
+ * 
+ * Copyright (c) 2003-2005, Ericsson Research Canada
+ * Copyright (c) 2005, Wind River Systems
+ * Copyright (c) 2005-2006, Ericsson AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this 
+ * list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright notice, 
+ * this list of conditions and the following disclaimer in the documentation 
+ * and/or other materials provided with the distribution.
+ * Neither the names of the copyright holders nor the names of its 
+ * contributors may be used to endorse or promote products derived from this 
+ * software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _TIPC_REF_H
+#define _TIPC_REF_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 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;
+};
+
+extern struct ref_table ref_table;
+
+int ref_table_init(u32 requested_size, u32 start);
+void ref_table_stop(void);
+
+u32 ref_acquire(void *object, spinlock_t **lock);
+void ref_discard(u32 ref);
+
+
+/**
+ * ref_lock - lock referenced object and return pointer to it
+ */
+
+static inline void *ref_lock(u32 ref)
+{
+	if (likely(ref_table.entries)) {
+		struct reference *r =
+			&ref_table.entries[ref & ref_table.index_mask];
+
+		spin_lock_bh(&r->lock);
+		if (likely(r->data.reference == ref))
+			return r->object;
+		spin_unlock_bh(&r->lock);
+	}
+	return 0;
+}
+
+/**
+ * ref_unlock - unlock referenced object 
+ */
+
+static inline void ref_unlock(u32 ref)
+{
+	if (likely(ref_table.entries)) {
+		struct reference *r =
+			&ref_table.entries[ref & ref_table.index_mask];
+
+		if (likely(r->data.reference == ref))
+			spin_unlock_bh(&r->lock);
+		else
+			err("ref_unlock() invoked using obsolete reference\n");
+	}
+}
+
+/**
+ * ref_deref - return pointer referenced object (without locking it)
+ */
+
+static inline void *ref_deref(u32 ref)
+{
+	if (likely(ref_table.entries)) {
+		struct reference *r = 
+			&ref_table.entries[ref & ref_table.index_mask];
+
+		if (likely(r->data.reference == ref))
+			return r->object;
+	}
+	return 0;
+}
+
+#endif
-- 
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