trap signals for "-serial mon:stdio"
[qemu.git] / qemu-coroutine-lock.c
1 /*
2 * coroutine queues and locks
3 *
4 * Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com>
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "qemu-common.h"
26 #include "block/coroutine.h"
27 #include "block/coroutine_int.h"
28 #include "qemu/queue.h"
29 #include "trace.h"
30
31 void qemu_co_queue_init(CoQueue *queue)
32 {
33 QTAILQ_INIT(&queue->entries);
34 }
35
36 void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
37 {
38 Coroutine *self = qemu_coroutine_self();
39 QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
40 qemu_coroutine_yield();
41 assert(qemu_in_coroutine());
42 }
43
44 void coroutine_fn qemu_co_queue_wait_insert_head(CoQueue *queue)
45 {
46 Coroutine *self = qemu_coroutine_self();
47 QTAILQ_INSERT_HEAD(&queue->entries, self, co_queue_next);
48 qemu_coroutine_yield();
49 assert(qemu_in_coroutine());
50 }
51
52 /**
53 * qemu_co_queue_run_restart:
54 *
55 * Enter each coroutine that was previously marked for restart by
56 * qemu_co_queue_next() or qemu_co_queue_restart_all(). This function is
57 * invoked by the core coroutine code when the current coroutine yields or
58 * terminates.
59 */
60 void qemu_co_queue_run_restart(Coroutine *co)
61 {
62 Coroutine *next;
63
64 trace_qemu_co_queue_run_restart(co);
65 while ((next = QTAILQ_FIRST(&co->co_queue_wakeup))) {
66 QTAILQ_REMOVE(&co->co_queue_wakeup, next, co_queue_next);
67 qemu_coroutine_enter(next, NULL);
68 }
69 }
70
71 static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
72 {
73 Coroutine *self = qemu_coroutine_self();
74 Coroutine *next;
75
76 if (QTAILQ_EMPTY(&queue->entries)) {
77 return false;
78 }
79
80 while ((next = QTAILQ_FIRST(&queue->entries)) != NULL) {
81 QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
82 QTAILQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next);
83 trace_qemu_co_queue_next(next);
84 if (single) {
85 break;
86 }
87 }
88 return true;
89 }
90
91 bool qemu_co_queue_next(CoQueue *queue)
92 {
93 return qemu_co_queue_do_restart(queue, true);
94 }
95
96 void qemu_co_queue_restart_all(CoQueue *queue)
97 {
98 qemu_co_queue_do_restart(queue, false);
99 }
100
101 bool qemu_co_queue_empty(CoQueue *queue)
102 {
103 return (QTAILQ_FIRST(&queue->entries) == NULL);
104 }
105
106 void qemu_co_mutex_init(CoMutex *mutex)
107 {
108 memset(mutex, 0, sizeof(*mutex));
109 qemu_co_queue_init(&mutex->queue);
110 }
111
112 void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
113 {
114 Coroutine *self = qemu_coroutine_self();
115
116 trace_qemu_co_mutex_lock_entry(mutex, self);
117
118 while (mutex->locked) {
119 qemu_co_queue_wait(&mutex->queue);
120 }
121
122 mutex->locked = true;
123
124 trace_qemu_co_mutex_lock_return(mutex, self);
125 }
126
127 void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
128 {
129 Coroutine *self = qemu_coroutine_self();
130
131 trace_qemu_co_mutex_unlock_entry(mutex, self);
132
133 assert(mutex->locked == true);
134 assert(qemu_in_coroutine());
135
136 mutex->locked = false;
137 qemu_co_queue_next(&mutex->queue);
138
139 trace_qemu_co_mutex_unlock_return(mutex, self);
140 }
141
142 void qemu_co_rwlock_init(CoRwlock *lock)
143 {
144 memset(lock, 0, sizeof(*lock));
145 qemu_co_queue_init(&lock->queue);
146 }
147
148 void qemu_co_rwlock_rdlock(CoRwlock *lock)
149 {
150 while (lock->writer) {
151 qemu_co_queue_wait(&lock->queue);
152 }
153 lock->reader++;
154 }
155
156 void qemu_co_rwlock_unlock(CoRwlock *lock)
157 {
158 assert(qemu_in_coroutine());
159 if (lock->writer) {
160 lock->writer = false;
161 qemu_co_queue_restart_all(&lock->queue);
162 } else {
163 lock->reader--;
164 assert(lock->reader >= 0);
165 /* Wakeup only one waiting writer */
166 if (!lock->reader) {
167 qemu_co_queue_next(&lock->queue);
168 }
169 }
170 }
171
172 void qemu_co_rwlock_wrlock(CoRwlock *lock)
173 {
174 while (lock->writer || lock->reader) {
175 qemu_co_queue_wait(&lock->queue);
176 }
177 lock->writer = true;
178 }