diff options
author | Per Liden <per.liden@nospam.ericsson.com> | 2006-01-02 13:04:38 -0500 |
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committer | David S. Miller <davem@sunset.davemloft.net> | 2006-01-12 17:06:31 -0500 |
commit | b97bf3fd8f6a16966d4f18983b2c40993ff937d4 (patch) | |
tree | 59959f8a0f3087455efdcb430846686f303c5991 /net/tipc/ref.c | |
parent | 58cba4650a7a414eabd2b40cc9d8e45fcdf192d9 (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>
Diffstat (limited to 'net/tipc/ref.c')
-rw-r--r-- | net/tipc/ref.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/net/tipc/ref.c b/net/tipc/ref.c new file mode 100644 index 000000000000..aee48c797b1e --- /dev/null +++ b/net/tipc/ref.c | |||
@@ -0,0 +1,186 @@ | |||
1 | /* | ||
2 | * net/tipc/ref.c: TIPC object registry code | ||
3 | * | ||
4 | * Copyright (c) 2003-2005, Ericsson Research Canada | ||
5 | * Copyright (c) 2004-2005, 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 | #include "core.h" | ||
35 | #include "ref.h" | ||
36 | #include "port.h" | ||
37 | #include "subscr.h" | ||
38 | #include "name_distr.h" | ||
39 | #include "name_table.h" | ||
40 | #include "config.h" | ||
41 | #include "discover.h" | ||
42 | #include "bearer.h" | ||
43 | #include "node.h" | ||
44 | #include "bcast.h" | ||
45 | |||
46 | /* | ||
47 | * Object reference table consists of 2**N entries. | ||
48 | * | ||
49 | * A used entry has object ptr != 0, reference == XXXX|own index | ||
50 | * (XXXX changes each time entry is acquired) | ||
51 | * A free entry has object ptr == 0, reference == YYYY|next free index | ||
52 | * (YYYY is one more than last used XXXX) | ||
53 | * | ||
54 | * Free list is initially chained from entry (2**N)-1 to entry 1. | ||
55 | * Entry 0 is not used to allow index 0 to indicate the end of the free list. | ||
56 | * | ||
57 | * Note: Any accidental reference of the form XXXX|0--0 won't match entry 0 | ||
58 | * because entry 0's reference field has the form XXXX|1--1. | ||
59 | */ | ||
60 | |||
61 | struct ref_table ref_table = { 0 }; | ||
62 | |||
63 | rwlock_t reftbl_lock = RW_LOCK_UNLOCKED; | ||
64 | |||
65 | /** | ||
66 | * ref_table_init - create reference table for objects | ||
67 | */ | ||
68 | |||
69 | int ref_table_init(u32 requested_size, u32 start) | ||
70 | { | ||
71 | struct reference *table; | ||
72 | u32 sz = 1 << 4; | ||
73 | u32 index_mask; | ||
74 | int i; | ||
75 | |||
76 | while (sz < requested_size) { | ||
77 | sz <<= 1; | ||
78 | } | ||
79 | table = (struct reference *)vmalloc(sz * sizeof(struct reference)); | ||
80 | if (table == NULL) | ||
81 | return -ENOMEM; | ||
82 | |||
83 | write_lock_bh(&reftbl_lock); | ||
84 | index_mask = sz - 1; | ||
85 | for (i = sz - 1; i >= 0; i--) { | ||
86 | table[i].object = 0; | ||
87 | table[i].lock = SPIN_LOCK_UNLOCKED; | ||
88 | table[i].data.next_plus_upper = (start & ~index_mask) + i - 1; | ||
89 | } | ||
90 | ref_table.entries = table; | ||
91 | ref_table.index_mask = index_mask; | ||
92 | ref_table.first_free = sz - 1; | ||
93 | ref_table.last_free = 1; | ||
94 | write_unlock_bh(&reftbl_lock); | ||
95 | return TIPC_OK; | ||
96 | } | ||
97 | |||
98 | /** | ||
99 | * ref_table_stop - destroy reference table for objects | ||
100 | */ | ||
101 | |||
102 | void ref_table_stop(void) | ||
103 | { | ||
104 | if (!ref_table.entries) | ||
105 | return; | ||
106 | |||
107 | vfree(ref_table.entries); | ||
108 | ref_table.entries = 0; | ||
109 | } | ||
110 | |||
111 | /** | ||
112 | * ref_acquire - create reference to an object | ||
113 | * | ||
114 | * Return a unique reference value which can be translated back to the pointer | ||
115 | * 'object' at a later time. Also, pass back a pointer to the lock protecting | ||
116 | * the object, but without locking it. | ||
117 | */ | ||
118 | |||
119 | u32 ref_acquire(void *object, spinlock_t **lock) | ||
120 | { | ||
121 | struct reference *entry; | ||
122 | u32 index; | ||
123 | u32 index_mask; | ||
124 | u32 next_plus_upper; | ||
125 | u32 reference = 0; | ||
126 | |||
127 | assert(ref_table.entries && object); | ||
128 | |||
129 | write_lock_bh(&reftbl_lock); | ||
130 | if (ref_table.first_free) { | ||
131 | index = ref_table.first_free; | ||
132 | entry = &(ref_table.entries[index]); | ||
133 | index_mask = ref_table.index_mask; | ||
134 | /* take lock in case a previous user of entry still holds it */ | ||
135 | spin_lock_bh(&entry->lock); | ||
136 | next_plus_upper = entry->data.next_plus_upper; | ||
137 | ref_table.first_free = next_plus_upper & index_mask; | ||
138 | reference = (next_plus_upper & ~index_mask) + index; | ||
139 | entry->data.reference = reference; | ||
140 | entry->object = object; | ||
141 | if (lock != 0) | ||
142 | *lock = &entry->lock; | ||
143 | spin_unlock_bh(&entry->lock); | ||
144 | } | ||
145 | write_unlock_bh(&reftbl_lock); | ||
146 | return reference; | ||
147 | } | ||
148 | |||
149 | /** | ||
150 | * ref_discard - invalidate references to an object | ||
151 | * | ||
152 | * Disallow future references to an object and free up the entry for re-use. | ||
153 | * Note: The entry's spin_lock may still be busy after discard | ||
154 | */ | ||
155 | |||
156 | void ref_discard(u32 ref) | ||
157 | { | ||
158 | struct reference *entry; | ||
159 | u32 index; | ||
160 | u32 index_mask; | ||
161 | |||
162 | assert(ref_table.entries); | ||
163 | assert(ref != 0); | ||
164 | |||
165 | write_lock_bh(&reftbl_lock); | ||
166 | index_mask = ref_table.index_mask; | ||
167 | index = ref & index_mask; | ||
168 | entry = &(ref_table.entries[index]); | ||
169 | assert(entry->object != 0); | ||
170 | assert(entry->data.reference == ref); | ||
171 | |||
172 | /* mark entry as unused */ | ||
173 | entry->object = 0; | ||
174 | if (ref_table.first_free == 0) | ||
175 | ref_table.first_free = index; | ||
176 | else | ||
177 | /* next_plus_upper is always XXXX|0--0 for last free entry */ | ||
178 | ref_table.entries[ref_table.last_free].data.next_plus_upper | ||
179 | |= index; | ||
180 | ref_table.last_free = index; | ||
181 | |||
182 | /* increment upper bits of entry to invalidate subsequent references */ | ||
183 | entry->data.next_plus_upper = (ref & ~index_mask) + (index_mask + 1); | ||
184 | write_unlock_bh(&reftbl_lock); | ||
185 | } | ||
186 | |||