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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/*
* net/tipc/ref.c: TIPC object registry code
*
* Copyright (c) 2003-2005, Ericsson Research Canada
* Copyright (c) 2004-2005, 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.
*/
#include "core.h"
#include "ref.h"
#include "port.h"
#include "subscr.h"
#include "name_distr.h"
#include "name_table.h"
#include "config.h"
#include "discover.h"
#include "bearer.h"
#include "node.h"
#include "bcast.h"
/*
* Object reference table consists of 2**N entries.
*
* A used entry has object ptr != 0, reference == XXXX|own index
* (XXXX changes each time entry is acquired)
* A free entry has object ptr == 0, reference == YYYY|next free index
* (YYYY is one more than last used XXXX)
*
* Free list is initially chained from entry (2**N)-1 to entry 1.
* Entry 0 is not used to allow index 0 to indicate the end of the free list.
*
* Note: Any accidental reference of the form XXXX|0--0 won't match entry 0
* because entry 0's reference field has the form XXXX|1--1.
*/
struct ref_table ref_table = { 0 };
rwlock_t reftbl_lock = RW_LOCK_UNLOCKED;
/**
* ref_table_init - create reference table for objects
*/
int ref_table_init(u32 requested_size, u32 start)
{
struct reference *table;
u32 sz = 1 << 4;
u32 index_mask;
int i;
while (sz < requested_size) {
sz <<= 1;
}
table = (struct reference *)vmalloc(sz * sizeof(struct reference));
if (table == NULL)
return -ENOMEM;
write_lock_bh(&reftbl_lock);
index_mask = sz - 1;
for (i = sz - 1; i >= 0; i--) {
table[i].object = 0;
table[i].lock = SPIN_LOCK_UNLOCKED;
table[i].data.next_plus_upper = (start & ~index_mask) + i - 1;
}
ref_table.entries = table;
ref_table.index_mask = index_mask;
ref_table.first_free = sz - 1;
ref_table.last_free = 1;
write_unlock_bh(&reftbl_lock);
return TIPC_OK;
}
/**
* ref_table_stop - destroy reference table for objects
*/
void ref_table_stop(void)
{
if (!ref_table.entries)
return;
vfree(ref_table.entries);
ref_table.entries = 0;
}
/**
* ref_acquire - create reference to an object
*
* Return a unique reference value which can be translated back to the pointer
* 'object' at a later time. Also, pass back a pointer to the lock protecting
* the object, but without locking it.
*/
u32 ref_acquire(void *object, spinlock_t **lock)
{
struct reference *entry;
u32 index;
u32 index_mask;
u32 next_plus_upper;
u32 reference = 0;
assert(ref_table.entries && object);
write_lock_bh(&reftbl_lock);
if (ref_table.first_free) {
index = ref_table.first_free;
entry = &(ref_table.entries[index]);
index_mask = ref_table.index_mask;
/* take lock in case a previous user of entry still holds it */
spin_lock_bh(&entry->lock);
next_plus_upper = entry->data.next_plus_upper;
ref_table.first_free = next_plus_upper & index_mask;
reference = (next_plus_upper & ~index_mask) + index;
entry->data.reference = reference;
entry->object = object;
if (lock != 0)
*lock = &entry->lock;
spin_unlock_bh(&entry->lock);
}
write_unlock_bh(&reftbl_lock);
return reference;
}
/**
* ref_discard - invalidate references to an object
*
* Disallow future references to an object and free up the entry for re-use.
* Note: The entry's spin_lock may still be busy after discard
*/
void ref_discard(u32 ref)
{
struct reference *entry;
u32 index;
u32 index_mask;
assert(ref_table.entries);
assert(ref != 0);
write_lock_bh(&reftbl_lock);
index_mask = ref_table.index_mask;
index = ref & index_mask;
entry = &(ref_table.entries[index]);
assert(entry->object != 0);
assert(entry->data.reference == ref);
/* mark entry as unused */
entry->object = 0;
if (ref_table.first_free == 0)
ref_table.first_free = index;
else
/* next_plus_upper is always XXXX|0--0 for last free entry */
ref_table.entries[ref_table.last_free].data.next_plus_upper
|= index;
ref_table.last_free = index;
/* increment upper bits of entry to invalidate subsequent references */
entry->data.next_plus_upper = (ref & ~index_mask) + (index_mask + 1);
write_unlock_bh(&reftbl_lock);
}
|
