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authorPer Liden <per.liden@nospam.ericsson.com>2006-01-02 13:04:38 -0500
committerDavid S. Miller <davem@sunset.davemloft.net>2006-01-12 17:06:31 -0500
commitb97bf3fd8f6a16966d4f18983b2c40993ff937d4 (patch)
tree59959f8a0f3087455efdcb430846686f303c5991 /net/tipc/ref.h
parent58cba4650a7a414eabd2b40cc9d8e45fcdf192d9 (diff)
[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>
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1/*
2 * net/tipc/ref.h: Include file for TIPC object registry code
3 *
4 * Copyright (c) 2003-2005, Ericsson Research Canada
5 * Copyright (c) 2005, Wind River Systems
6 * Copyright (c) 2005-2006, Ericsson AB
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions are met:
11 *
12 * Redistributions of source code must retain the above copyright notice, this
13 * list of conditions and the following disclaimer.
14 * Redistributions in binary form must reproduce the above copyright notice,
15 * this list of conditions and the following disclaimer in the documentation
16 * and/or other materials provided with the distribution.
17 * Neither the names of the copyright holders nor the names of its
18 * contributors may be used to endorse or promote products derived from this
19 * software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#ifndef _TIPC_REF_H
35#define _TIPC_REF_H
36
37/**
38 * struct reference - TIPC object reference entry
39 * @object: pointer to object associated with reference entry
40 * @lock: spinlock controlling access to object
41 * @data: reference value associated with object (or link to next unused entry)
42 */
43
44struct reference {
45 void *object;
46 spinlock_t lock;
47 union {
48 u32 next_plus_upper;
49 u32 reference;
50 } data;
51};
52
53/**
54 * struct ref_table - table of TIPC object reference entries
55 * @entries: pointer to array of reference entries
56 * @index_mask: bitmask for array index portion of reference values
57 * @first_free: array index of first unused object reference entry
58 * @last_free: array index of last unused object reference entry
59 */
60
61struct ref_table {
62 struct reference *entries;
63 u32 index_mask;
64 u32 first_free;
65 u32 last_free;
66};
67
68extern struct ref_table ref_table;
69
70int ref_table_init(u32 requested_size, u32 start);
71void ref_table_stop(void);
72
73u32 ref_acquire(void *object, spinlock_t **lock);
74void ref_discard(u32 ref);
75
76
77/**
78 * ref_lock - lock referenced object and return pointer to it
79 */
80
81static inline void *ref_lock(u32 ref)
82{
83 if (likely(ref_table.entries)) {
84 struct reference *r =
85 &ref_table.entries[ref & ref_table.index_mask];
86
87 spin_lock_bh(&r->lock);
88 if (likely(r->data.reference == ref))
89 return r->object;
90 spin_unlock_bh(&r->lock);
91 }
92 return 0;
93}
94
95/**
96 * ref_unlock - unlock referenced object
97 */
98
99static inline void ref_unlock(u32 ref)
100{
101 if (likely(ref_table.entries)) {
102 struct reference *r =
103 &ref_table.entries[ref & ref_table.index_mask];
104
105 if (likely(r->data.reference == ref))
106 spin_unlock_bh(&r->lock);
107 else
108 err("ref_unlock() invoked using obsolete reference\n");
109 }
110}
111
112/**
113 * ref_deref - return pointer referenced object (without locking it)
114 */
115
116static inline void *ref_deref(u32 ref)
117{
118 if (likely(ref_table.entries)) {
119 struct reference *r =
120 &ref_table.entries[ref & ref_table.index_mask];
121
122 if (likely(r->data.reference == ref))
123 return r->object;
124 }
125 return 0;
126}
127
128#endif