1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
/*
* 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:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. 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.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* 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
|
