root / qemu-coroutine-lock.c @ 85e8dab1
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1 | b96e9247 | Kevin Wolf | /*
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2 | b96e9247 | Kevin Wolf | * coroutine queues and locks
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3 | b96e9247 | Kevin Wolf | *
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4 | b96e9247 | Kevin Wolf | * Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com>
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5 | b96e9247 | Kevin Wolf | *
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6 | b96e9247 | Kevin Wolf | * Permission is hereby granted, free of charge, to any person obtaining a copy
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7 | b96e9247 | Kevin Wolf | * of this software and associated documentation files (the "Software"), to deal
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8 | b96e9247 | Kevin Wolf | * in the Software without restriction, including without limitation the rights
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9 | b96e9247 | Kevin Wolf | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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10 | b96e9247 | Kevin Wolf | * copies of the Software, and to permit persons to whom the Software is
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11 | b96e9247 | Kevin Wolf | * furnished to do so, subject to the following conditions:
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12 | b96e9247 | Kevin Wolf | *
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13 | b96e9247 | Kevin Wolf | * The above copyright notice and this permission notice shall be included in
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14 | b96e9247 | Kevin Wolf | * all copies or substantial portions of the Software.
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15 | b96e9247 | Kevin Wolf | *
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16 | b96e9247 | Kevin Wolf | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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17 | b96e9247 | Kevin Wolf | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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18 | b96e9247 | Kevin Wolf | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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19 | b96e9247 | Kevin Wolf | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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20 | b96e9247 | Kevin Wolf | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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21 | b96e9247 | Kevin Wolf | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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22 | b96e9247 | Kevin Wolf | * THE SOFTWARE.
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23 | b96e9247 | Kevin Wolf | */
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24 | b96e9247 | Kevin Wolf | |
25 | b96e9247 | Kevin Wolf | #include "qemu-common.h" |
26 | b96e9247 | Kevin Wolf | #include "qemu-coroutine.h" |
27 | b96e9247 | Kevin Wolf | #include "qemu-coroutine-int.h" |
28 | b96e9247 | Kevin Wolf | #include "qemu-queue.h" |
29 | 44a9b356 | Paolo Bonzini | #include "main-loop.h" |
30 | b96e9247 | Kevin Wolf | #include "trace.h" |
31 | b96e9247 | Kevin Wolf | |
32 | b96e9247 | Kevin Wolf | static QTAILQ_HEAD(, Coroutine) unlock_bh_queue =
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33 | b96e9247 | Kevin Wolf | QTAILQ_HEAD_INITIALIZER(unlock_bh_queue); |
34 | e680cfa7 | Kevin Wolf | static QEMUBH* unlock_bh;
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35 | b96e9247 | Kevin Wolf | |
36 | b96e9247 | Kevin Wolf | static void qemu_co_queue_next_bh(void *opaque) |
37 | b96e9247 | Kevin Wolf | { |
38 | b96e9247 | Kevin Wolf | Coroutine *next; |
39 | b96e9247 | Kevin Wolf | |
40 | b96e9247 | Kevin Wolf | trace_qemu_co_queue_next_bh(); |
41 | b96e9247 | Kevin Wolf | while ((next = QTAILQ_FIRST(&unlock_bh_queue))) {
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42 | b96e9247 | Kevin Wolf | QTAILQ_REMOVE(&unlock_bh_queue, next, co_queue_next); |
43 | b96e9247 | Kevin Wolf | qemu_coroutine_enter(next, NULL);
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44 | b96e9247 | Kevin Wolf | } |
45 | b96e9247 | Kevin Wolf | } |
46 | b96e9247 | Kevin Wolf | |
47 | b96e9247 | Kevin Wolf | void qemu_co_queue_init(CoQueue *queue)
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48 | b96e9247 | Kevin Wolf | { |
49 | b96e9247 | Kevin Wolf | QTAILQ_INIT(&queue->entries); |
50 | e680cfa7 | Kevin Wolf | |
51 | e680cfa7 | Kevin Wolf | if (!unlock_bh) {
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52 | e680cfa7 | Kevin Wolf | unlock_bh = qemu_bh_new(qemu_co_queue_next_bh, NULL);
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53 | e680cfa7 | Kevin Wolf | } |
54 | b96e9247 | Kevin Wolf | } |
55 | b96e9247 | Kevin Wolf | |
56 | b96e9247 | Kevin Wolf | void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
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57 | b96e9247 | Kevin Wolf | { |
58 | b96e9247 | Kevin Wolf | Coroutine *self = qemu_coroutine_self(); |
59 | b96e9247 | Kevin Wolf | QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next); |
60 | b96e9247 | Kevin Wolf | qemu_coroutine_yield(); |
61 | b96e9247 | Kevin Wolf | assert(qemu_in_coroutine()); |
62 | b96e9247 | Kevin Wolf | } |
63 | b96e9247 | Kevin Wolf | |
64 | e9e6295b | Zhi Yong Wu | void coroutine_fn qemu_co_queue_wait_insert_head(CoQueue *queue)
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65 | e9e6295b | Zhi Yong Wu | { |
66 | e9e6295b | Zhi Yong Wu | Coroutine *self = qemu_coroutine_self(); |
67 | e9e6295b | Zhi Yong Wu | QTAILQ_INSERT_HEAD(&queue->entries, self, co_queue_next); |
68 | e9e6295b | Zhi Yong Wu | qemu_coroutine_yield(); |
69 | e9e6295b | Zhi Yong Wu | assert(qemu_in_coroutine()); |
70 | e9e6295b | Zhi Yong Wu | } |
71 | e9e6295b | Zhi Yong Wu | |
72 | b96e9247 | Kevin Wolf | bool qemu_co_queue_next(CoQueue *queue)
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73 | b96e9247 | Kevin Wolf | { |
74 | b96e9247 | Kevin Wolf | Coroutine *next; |
75 | b96e9247 | Kevin Wolf | |
76 | b96e9247 | Kevin Wolf | next = QTAILQ_FIRST(&queue->entries); |
77 | b96e9247 | Kevin Wolf | if (next) {
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78 | b96e9247 | Kevin Wolf | QTAILQ_REMOVE(&queue->entries, next, co_queue_next); |
79 | b96e9247 | Kevin Wolf | QTAILQ_INSERT_TAIL(&unlock_bh_queue, next, co_queue_next); |
80 | b96e9247 | Kevin Wolf | trace_qemu_co_queue_next(next); |
81 | e680cfa7 | Kevin Wolf | qemu_bh_schedule(unlock_bh); |
82 | b96e9247 | Kevin Wolf | } |
83 | b96e9247 | Kevin Wolf | |
84 | b96e9247 | Kevin Wolf | return (next != NULL); |
85 | b96e9247 | Kevin Wolf | } |
86 | b96e9247 | Kevin Wolf | |
87 | e8ee5e4c | Stefan Hajnoczi | void qemu_co_queue_restart_all(CoQueue *queue)
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88 | e8ee5e4c | Stefan Hajnoczi | { |
89 | e8ee5e4c | Stefan Hajnoczi | while (qemu_co_queue_next(queue)) {
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90 | e8ee5e4c | Stefan Hajnoczi | /* Do nothing */
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91 | e8ee5e4c | Stefan Hajnoczi | } |
92 | e8ee5e4c | Stefan Hajnoczi | } |
93 | e8ee5e4c | Stefan Hajnoczi | |
94 | b96e9247 | Kevin Wolf | bool qemu_co_queue_empty(CoQueue *queue)
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95 | b96e9247 | Kevin Wolf | { |
96 | b96e9247 | Kevin Wolf | return (QTAILQ_FIRST(&queue->entries) == NULL); |
97 | b96e9247 | Kevin Wolf | } |
98 | b96e9247 | Kevin Wolf | |
99 | b96e9247 | Kevin Wolf | void qemu_co_mutex_init(CoMutex *mutex)
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100 | b96e9247 | Kevin Wolf | { |
101 | b96e9247 | Kevin Wolf | memset(mutex, 0, sizeof(*mutex)); |
102 | b96e9247 | Kevin Wolf | qemu_co_queue_init(&mutex->queue); |
103 | b96e9247 | Kevin Wolf | } |
104 | b96e9247 | Kevin Wolf | |
105 | b96e9247 | Kevin Wolf | void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
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106 | b96e9247 | Kevin Wolf | { |
107 | b96e9247 | Kevin Wolf | Coroutine *self = qemu_coroutine_self(); |
108 | b96e9247 | Kevin Wolf | |
109 | b96e9247 | Kevin Wolf | trace_qemu_co_mutex_lock_entry(mutex, self); |
110 | b96e9247 | Kevin Wolf | |
111 | b96e9247 | Kevin Wolf | while (mutex->locked) {
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112 | b96e9247 | Kevin Wolf | qemu_co_queue_wait(&mutex->queue); |
113 | b96e9247 | Kevin Wolf | } |
114 | b96e9247 | Kevin Wolf | |
115 | b96e9247 | Kevin Wolf | mutex->locked = true;
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116 | b96e9247 | Kevin Wolf | |
117 | b96e9247 | Kevin Wolf | trace_qemu_co_mutex_lock_return(mutex, self); |
118 | b96e9247 | Kevin Wolf | } |
119 | b96e9247 | Kevin Wolf | |
120 | b96e9247 | Kevin Wolf | void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
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121 | b96e9247 | Kevin Wolf | { |
122 | b96e9247 | Kevin Wolf | Coroutine *self = qemu_coroutine_self(); |
123 | b96e9247 | Kevin Wolf | |
124 | b96e9247 | Kevin Wolf | trace_qemu_co_mutex_unlock_entry(mutex, self); |
125 | b96e9247 | Kevin Wolf | |
126 | b96e9247 | Kevin Wolf | assert(mutex->locked == true);
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127 | b96e9247 | Kevin Wolf | assert(qemu_in_coroutine()); |
128 | b96e9247 | Kevin Wolf | |
129 | b96e9247 | Kevin Wolf | mutex->locked = false;
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130 | b96e9247 | Kevin Wolf | qemu_co_queue_next(&mutex->queue); |
131 | b96e9247 | Kevin Wolf | |
132 | b96e9247 | Kevin Wolf | trace_qemu_co_mutex_unlock_return(mutex, self); |
133 | b96e9247 | Kevin Wolf | } |
134 | 12888904 | Aneesh Kumar K.V | |
135 | 12888904 | Aneesh Kumar K.V | void qemu_co_rwlock_init(CoRwlock *lock)
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136 | 12888904 | Aneesh Kumar K.V | { |
137 | 12888904 | Aneesh Kumar K.V | memset(lock, 0, sizeof(*lock)); |
138 | 12888904 | Aneesh Kumar K.V | qemu_co_queue_init(&lock->queue); |
139 | 12888904 | Aneesh Kumar K.V | } |
140 | 12888904 | Aneesh Kumar K.V | |
141 | 12888904 | Aneesh Kumar K.V | void qemu_co_rwlock_rdlock(CoRwlock *lock)
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142 | 12888904 | Aneesh Kumar K.V | { |
143 | 12888904 | Aneesh Kumar K.V | while (lock->writer) {
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144 | 12888904 | Aneesh Kumar K.V | qemu_co_queue_wait(&lock->queue); |
145 | 12888904 | Aneesh Kumar K.V | } |
146 | 12888904 | Aneesh Kumar K.V | lock->reader++; |
147 | 12888904 | Aneesh Kumar K.V | } |
148 | 12888904 | Aneesh Kumar K.V | |
149 | 12888904 | Aneesh Kumar K.V | void qemu_co_rwlock_unlock(CoRwlock *lock)
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150 | 12888904 | Aneesh Kumar K.V | { |
151 | 12888904 | Aneesh Kumar K.V | assert(qemu_in_coroutine()); |
152 | 12888904 | Aneesh Kumar K.V | if (lock->writer) {
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153 | 12888904 | Aneesh Kumar K.V | lock->writer = false;
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154 | e8ee5e4c | Stefan Hajnoczi | qemu_co_queue_restart_all(&lock->queue); |
155 | 12888904 | Aneesh Kumar K.V | } else {
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156 | 12888904 | Aneesh Kumar K.V | lock->reader--; |
157 | 12888904 | Aneesh Kumar K.V | assert(lock->reader >= 0);
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158 | 12888904 | Aneesh Kumar K.V | /* Wakeup only one waiting writer */
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159 | 12888904 | Aneesh Kumar K.V | if (!lock->reader) {
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160 | 12888904 | Aneesh Kumar K.V | qemu_co_queue_next(&lock->queue); |
161 | 12888904 | Aneesh Kumar K.V | } |
162 | 12888904 | Aneesh Kumar K.V | } |
163 | 12888904 | Aneesh Kumar K.V | } |
164 | 12888904 | Aneesh Kumar K.V | |
165 | 12888904 | Aneesh Kumar K.V | void qemu_co_rwlock_wrlock(CoRwlock *lock)
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166 | 12888904 | Aneesh Kumar K.V | { |
167 | 12888904 | Aneesh Kumar K.V | while (lock->writer || lock->reader) {
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168 | 12888904 | Aneesh Kumar K.V | qemu_co_queue_wait(&lock->queue); |
169 | 12888904 | Aneesh Kumar K.V | } |
170 | 12888904 | Aneesh Kumar K.V | lock->writer = true;
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171 | 12888904 | Aneesh Kumar K.V | } |