root / qemu-coroutine-lock.c @ feature-archipelago
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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 | 737e150e | Paolo Bonzini | #include "block/coroutine.h" |
27 | 737e150e | Paolo Bonzini | #include "block/coroutine_int.h" |
28 | 1de7afc9 | Paolo Bonzini | #include "qemu/queue.h" |
29 | b96e9247 | Kevin Wolf | #include "trace.h" |
30 | b96e9247 | Kevin Wolf | |
31 | b96e9247 | Kevin Wolf | void qemu_co_queue_init(CoQueue *queue)
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32 | b96e9247 | Kevin Wolf | { |
33 | b96e9247 | Kevin Wolf | QTAILQ_INIT(&queue->entries); |
34 | b96e9247 | Kevin Wolf | } |
35 | b96e9247 | Kevin Wolf | |
36 | b96e9247 | Kevin Wolf | void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
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37 | b96e9247 | Kevin Wolf | { |
38 | b96e9247 | Kevin Wolf | Coroutine *self = qemu_coroutine_self(); |
39 | b96e9247 | Kevin Wolf | QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next); |
40 | b96e9247 | Kevin Wolf | qemu_coroutine_yield(); |
41 | b96e9247 | Kevin Wolf | assert(qemu_in_coroutine()); |
42 | b96e9247 | Kevin Wolf | } |
43 | b96e9247 | Kevin Wolf | |
44 | 02ffb504 | Stefan Hajnoczi | /**
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45 | 02ffb504 | Stefan Hajnoczi | * qemu_co_queue_run_restart:
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46 | 02ffb504 | Stefan Hajnoczi | *
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47 | 02ffb504 | Stefan Hajnoczi | * Enter each coroutine that was previously marked for restart by
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48 | 02ffb504 | Stefan Hajnoczi | * qemu_co_queue_next() or qemu_co_queue_restart_all(). This function is
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49 | 02ffb504 | Stefan Hajnoczi | * invoked by the core coroutine code when the current coroutine yields or
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50 | 02ffb504 | Stefan Hajnoczi | * terminates.
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51 | 02ffb504 | Stefan Hajnoczi | */
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52 | 02ffb504 | Stefan Hajnoczi | void qemu_co_queue_run_restart(Coroutine *co)
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53 | 02ffb504 | Stefan Hajnoczi | { |
54 | 02ffb504 | Stefan Hajnoczi | Coroutine *next; |
55 | 02ffb504 | Stefan Hajnoczi | |
56 | 02ffb504 | Stefan Hajnoczi | trace_qemu_co_queue_run_restart(co); |
57 | 02ffb504 | Stefan Hajnoczi | while ((next = QTAILQ_FIRST(&co->co_queue_wakeup))) {
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58 | 02ffb504 | Stefan Hajnoczi | QTAILQ_REMOVE(&co->co_queue_wakeup, next, co_queue_next); |
59 | 02ffb504 | Stefan Hajnoczi | qemu_coroutine_enter(next, NULL);
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60 | 02ffb504 | Stefan Hajnoczi | } |
61 | 02ffb504 | Stefan Hajnoczi | } |
62 | 02ffb504 | Stefan Hajnoczi | |
63 | 28f08246 | Stefan Hajnoczi | static bool qemu_co_queue_do_restart(CoQueue *queue, bool single) |
64 | b96e9247 | Kevin Wolf | { |
65 | 02ffb504 | Stefan Hajnoczi | Coroutine *self = qemu_coroutine_self(); |
66 | b96e9247 | Kevin Wolf | Coroutine *next; |
67 | 28f08246 | Stefan Hajnoczi | |
68 | 28f08246 | Stefan Hajnoczi | if (QTAILQ_EMPTY(&queue->entries)) {
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69 | 28f08246 | Stefan Hajnoczi | return false; |
70 | 28f08246 | Stefan Hajnoczi | } |
71 | b96e9247 | Kevin Wolf | |
72 | 28f08246 | Stefan Hajnoczi | while ((next = QTAILQ_FIRST(&queue->entries)) != NULL) { |
73 | b96e9247 | Kevin Wolf | QTAILQ_REMOVE(&queue->entries, next, co_queue_next); |
74 | 02ffb504 | Stefan Hajnoczi | QTAILQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next); |
75 | b96e9247 | Kevin Wolf | trace_qemu_co_queue_next(next); |
76 | 28f08246 | Stefan Hajnoczi | if (single) {
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77 | 28f08246 | Stefan Hajnoczi | break;
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78 | 28f08246 | Stefan Hajnoczi | } |
79 | b96e9247 | Kevin Wolf | } |
80 | 28f08246 | Stefan Hajnoczi | return true; |
81 | 28f08246 | Stefan Hajnoczi | } |
82 | b96e9247 | Kevin Wolf | |
83 | b681a1c7 | Benoît Canet | bool coroutine_fn qemu_co_queue_next(CoQueue *queue)
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84 | 28f08246 | Stefan Hajnoczi | { |
85 | b681a1c7 | Benoît Canet | assert(qemu_in_coroutine()); |
86 | 28f08246 | Stefan Hajnoczi | return qemu_co_queue_do_restart(queue, true); |
87 | b96e9247 | Kevin Wolf | } |
88 | b96e9247 | Kevin Wolf | |
89 | b681a1c7 | Benoît Canet | void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue)
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90 | e8ee5e4c | Stefan Hajnoczi | { |
91 | b681a1c7 | Benoît Canet | assert(qemu_in_coroutine()); |
92 | 28f08246 | Stefan Hajnoczi | qemu_co_queue_do_restart(queue, false);
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93 | e8ee5e4c | Stefan Hajnoczi | } |
94 | e8ee5e4c | Stefan Hajnoczi | |
95 | b681a1c7 | Benoît Canet | bool qemu_co_enter_next(CoQueue *queue)
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96 | b681a1c7 | Benoît Canet | { |
97 | b681a1c7 | Benoît Canet | Coroutine *next; |
98 | b681a1c7 | Benoît Canet | |
99 | b681a1c7 | Benoît Canet | next = QTAILQ_FIRST(&queue->entries); |
100 | b681a1c7 | Benoît Canet | if (!next) {
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101 | b681a1c7 | Benoît Canet | return false; |
102 | b681a1c7 | Benoît Canet | } |
103 | b681a1c7 | Benoît Canet | |
104 | b681a1c7 | Benoît Canet | QTAILQ_REMOVE(&queue->entries, next, co_queue_next); |
105 | b681a1c7 | Benoît Canet | qemu_coroutine_enter(next, NULL);
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106 | b681a1c7 | Benoît Canet | return true; |
107 | b681a1c7 | Benoît Canet | } |
108 | b681a1c7 | Benoît Canet | |
109 | b96e9247 | Kevin Wolf | bool qemu_co_queue_empty(CoQueue *queue)
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110 | b96e9247 | Kevin Wolf | { |
111 | b96e9247 | Kevin Wolf | return (QTAILQ_FIRST(&queue->entries) == NULL); |
112 | b96e9247 | Kevin Wolf | } |
113 | b96e9247 | Kevin Wolf | |
114 | b96e9247 | Kevin Wolf | void qemu_co_mutex_init(CoMutex *mutex)
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115 | b96e9247 | Kevin Wolf | { |
116 | b96e9247 | Kevin Wolf | memset(mutex, 0, sizeof(*mutex)); |
117 | b96e9247 | Kevin Wolf | qemu_co_queue_init(&mutex->queue); |
118 | b96e9247 | Kevin Wolf | } |
119 | b96e9247 | Kevin Wolf | |
120 | b96e9247 | Kevin Wolf | void coroutine_fn qemu_co_mutex_lock(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_lock_entry(mutex, self); |
125 | b96e9247 | Kevin Wolf | |
126 | b96e9247 | Kevin Wolf | while (mutex->locked) {
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127 | b96e9247 | Kevin Wolf | qemu_co_queue_wait(&mutex->queue); |
128 | b96e9247 | Kevin Wolf | } |
129 | b96e9247 | Kevin Wolf | |
130 | b96e9247 | Kevin Wolf | mutex->locked = true;
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131 | b96e9247 | Kevin Wolf | |
132 | b96e9247 | Kevin Wolf | trace_qemu_co_mutex_lock_return(mutex, self); |
133 | b96e9247 | Kevin Wolf | } |
134 | b96e9247 | Kevin Wolf | |
135 | b96e9247 | Kevin Wolf | void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
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136 | b96e9247 | Kevin Wolf | { |
137 | b96e9247 | Kevin Wolf | Coroutine *self = qemu_coroutine_self(); |
138 | b96e9247 | Kevin Wolf | |
139 | b96e9247 | Kevin Wolf | trace_qemu_co_mutex_unlock_entry(mutex, self); |
140 | b96e9247 | Kevin Wolf | |
141 | b96e9247 | Kevin Wolf | assert(mutex->locked == true);
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142 | b96e9247 | Kevin Wolf | assert(qemu_in_coroutine()); |
143 | b96e9247 | Kevin Wolf | |
144 | b96e9247 | Kevin Wolf | mutex->locked = false;
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145 | b96e9247 | Kevin Wolf | qemu_co_queue_next(&mutex->queue); |
146 | b96e9247 | Kevin Wolf | |
147 | b96e9247 | Kevin Wolf | trace_qemu_co_mutex_unlock_return(mutex, self); |
148 | b96e9247 | Kevin Wolf | } |
149 | 12888904 | Aneesh Kumar K.V | |
150 | 12888904 | Aneesh Kumar K.V | void qemu_co_rwlock_init(CoRwlock *lock)
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151 | 12888904 | Aneesh Kumar K.V | { |
152 | 12888904 | Aneesh Kumar K.V | memset(lock, 0, sizeof(*lock)); |
153 | 12888904 | Aneesh Kumar K.V | qemu_co_queue_init(&lock->queue); |
154 | 12888904 | Aneesh Kumar K.V | } |
155 | 12888904 | Aneesh Kumar K.V | |
156 | 12888904 | Aneesh Kumar K.V | void qemu_co_rwlock_rdlock(CoRwlock *lock)
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157 | 12888904 | Aneesh Kumar K.V | { |
158 | 12888904 | Aneesh Kumar K.V | while (lock->writer) {
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159 | 12888904 | Aneesh Kumar K.V | qemu_co_queue_wait(&lock->queue); |
160 | 12888904 | Aneesh Kumar K.V | } |
161 | 12888904 | Aneesh Kumar K.V | lock->reader++; |
162 | 12888904 | Aneesh Kumar K.V | } |
163 | 12888904 | Aneesh Kumar K.V | |
164 | 12888904 | Aneesh Kumar K.V | void qemu_co_rwlock_unlock(CoRwlock *lock)
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165 | 12888904 | Aneesh Kumar K.V | { |
166 | 12888904 | Aneesh Kumar K.V | assert(qemu_in_coroutine()); |
167 | 12888904 | Aneesh Kumar K.V | if (lock->writer) {
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168 | 12888904 | Aneesh Kumar K.V | lock->writer = false;
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169 | e8ee5e4c | Stefan Hajnoczi | qemu_co_queue_restart_all(&lock->queue); |
170 | 12888904 | Aneesh Kumar K.V | } else {
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171 | 12888904 | Aneesh Kumar K.V | lock->reader--; |
172 | 12888904 | Aneesh Kumar K.V | assert(lock->reader >= 0);
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173 | 12888904 | Aneesh Kumar K.V | /* Wakeup only one waiting writer */
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174 | 12888904 | Aneesh Kumar K.V | if (!lock->reader) {
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175 | 12888904 | Aneesh Kumar K.V | qemu_co_queue_next(&lock->queue); |
176 | 12888904 | Aneesh Kumar K.V | } |
177 | 12888904 | Aneesh Kumar K.V | } |
178 | 12888904 | Aneesh Kumar K.V | } |
179 | 12888904 | Aneesh Kumar K.V | |
180 | 12888904 | Aneesh Kumar K.V | void qemu_co_rwlock_wrlock(CoRwlock *lock)
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181 | 12888904 | Aneesh Kumar K.V | { |
182 | 12888904 | Aneesh Kumar K.V | while (lock->writer || lock->reader) {
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183 | 12888904 | Aneesh Kumar K.V | qemu_co_queue_wait(&lock->queue); |
184 | 12888904 | Aneesh Kumar K.V | } |
185 | 12888904 | Aneesh Kumar K.V | lock->writer = true;
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186 | 12888904 | Aneesh Kumar K.V | } |