Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 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 "qemu-coroutine.h" |
| 27 | #include "qemu-coroutine-int.h" |
| 28 | #include "qemu-queue.h" |
Paolo Bonzini | f627aab | 2012-10-29 23:45:23 +0100 | [diff] [blame] | 29 | #include "qemu-aio.h" |
Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 30 | #include "trace.h" |
| 31 | |
| 32 | static QTAILQ_HEAD(, Coroutine) unlock_bh_queue = |
| 33 | QTAILQ_HEAD_INITIALIZER(unlock_bh_queue); |
Kevin Wolf | e680cfa | 2011-07-13 15:42:52 +0200 | [diff] [blame] | 34 | static QEMUBH* unlock_bh; |
Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 35 | |
| 36 | static void qemu_co_queue_next_bh(void *opaque) |
| 37 | { |
Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 38 | Coroutine *next; |
| 39 | |
| 40 | trace_qemu_co_queue_next_bh(); |
| 41 | while ((next = QTAILQ_FIRST(&unlock_bh_queue))) { |
| 42 | QTAILQ_REMOVE(&unlock_bh_queue, next, co_queue_next); |
| 43 | qemu_coroutine_enter(next, NULL); |
| 44 | } |
Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 45 | } |
| 46 | |
| 47 | void qemu_co_queue_init(CoQueue *queue) |
| 48 | { |
| 49 | QTAILQ_INIT(&queue->entries); |
Kevin Wolf | e680cfa | 2011-07-13 15:42:52 +0200 | [diff] [blame] | 50 | |
| 51 | if (!unlock_bh) { |
| 52 | unlock_bh = qemu_bh_new(qemu_co_queue_next_bh, NULL); |
| 53 | } |
Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 54 | } |
| 55 | |
| 56 | void coroutine_fn qemu_co_queue_wait(CoQueue *queue) |
| 57 | { |
| 58 | Coroutine *self = qemu_coroutine_self(); |
| 59 | QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next); |
| 60 | qemu_coroutine_yield(); |
| 61 | assert(qemu_in_coroutine()); |
| 62 | } |
| 63 | |
Zhi Yong Wu | e9e6295 | 2011-11-03 16:57:26 +0800 | [diff] [blame] | 64 | void coroutine_fn qemu_co_queue_wait_insert_head(CoQueue *queue) |
| 65 | { |
| 66 | Coroutine *self = qemu_coroutine_self(); |
| 67 | QTAILQ_INSERT_HEAD(&queue->entries, self, co_queue_next); |
| 68 | qemu_coroutine_yield(); |
| 69 | assert(qemu_in_coroutine()); |
| 70 | } |
| 71 | |
Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 72 | bool qemu_co_queue_next(CoQueue *queue) |
| 73 | { |
Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 74 | Coroutine *next; |
| 75 | |
| 76 | next = QTAILQ_FIRST(&queue->entries); |
| 77 | if (next) { |
| 78 | QTAILQ_REMOVE(&queue->entries, next, co_queue_next); |
| 79 | QTAILQ_INSERT_TAIL(&unlock_bh_queue, next, co_queue_next); |
| 80 | trace_qemu_co_queue_next(next); |
Kevin Wolf | e680cfa | 2011-07-13 15:42:52 +0200 | [diff] [blame] | 81 | qemu_bh_schedule(unlock_bh); |
Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 82 | } |
| 83 | |
| 84 | return (next != NULL); |
| 85 | } |
| 86 | |
Stefan Hajnoczi | e8ee5e4 | 2011-11-17 13:40:26 +0000 | [diff] [blame] | 87 | void qemu_co_queue_restart_all(CoQueue *queue) |
| 88 | { |
| 89 | while (qemu_co_queue_next(queue)) { |
| 90 | /* Do nothing */ |
| 91 | } |
| 92 | } |
| 93 | |
Kevin Wolf | b96e924 | 2011-06-30 17:56:46 +0200 | [diff] [blame] | 94 | bool qemu_co_queue_empty(CoQueue *queue) |
| 95 | { |
| 96 | return (QTAILQ_FIRST(&queue->entries) == NULL); |
| 97 | } |
| 98 | |
| 99 | void qemu_co_mutex_init(CoMutex *mutex) |
| 100 | { |
| 101 | memset(mutex, 0, sizeof(*mutex)); |
| 102 | qemu_co_queue_init(&mutex->queue); |
| 103 | } |
| 104 | |
| 105 | void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex) |
| 106 | { |
| 107 | Coroutine *self = qemu_coroutine_self(); |
| 108 | |
| 109 | trace_qemu_co_mutex_lock_entry(mutex, self); |
| 110 | |
| 111 | while (mutex->locked) { |
| 112 | qemu_co_queue_wait(&mutex->queue); |
| 113 | } |
| 114 | |
| 115 | mutex->locked = true; |
| 116 | |
| 117 | trace_qemu_co_mutex_lock_return(mutex, self); |
| 118 | } |
| 119 | |
| 120 | void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex) |
| 121 | { |
| 122 | Coroutine *self = qemu_coroutine_self(); |
| 123 | |
| 124 | trace_qemu_co_mutex_unlock_entry(mutex, self); |
| 125 | |
| 126 | assert(mutex->locked == true); |
| 127 | assert(qemu_in_coroutine()); |
| 128 | |
| 129 | mutex->locked = false; |
| 130 | qemu_co_queue_next(&mutex->queue); |
| 131 | |
| 132 | trace_qemu_co_mutex_unlock_return(mutex, self); |
| 133 | } |
Aneesh Kumar K.V | 1288890 | 2011-08-02 12:02:51 +0530 | [diff] [blame] | 134 | |
| 135 | void qemu_co_rwlock_init(CoRwlock *lock) |
| 136 | { |
| 137 | memset(lock, 0, sizeof(*lock)); |
| 138 | qemu_co_queue_init(&lock->queue); |
| 139 | } |
| 140 | |
| 141 | void qemu_co_rwlock_rdlock(CoRwlock *lock) |
| 142 | { |
| 143 | while (lock->writer) { |
| 144 | qemu_co_queue_wait(&lock->queue); |
| 145 | } |
| 146 | lock->reader++; |
| 147 | } |
| 148 | |
| 149 | void qemu_co_rwlock_unlock(CoRwlock *lock) |
| 150 | { |
| 151 | assert(qemu_in_coroutine()); |
| 152 | if (lock->writer) { |
| 153 | lock->writer = false; |
Stefan Hajnoczi | e8ee5e4 | 2011-11-17 13:40:26 +0000 | [diff] [blame] | 154 | qemu_co_queue_restart_all(&lock->queue); |
Aneesh Kumar K.V | 1288890 | 2011-08-02 12:02:51 +0530 | [diff] [blame] | 155 | } else { |
| 156 | lock->reader--; |
| 157 | assert(lock->reader >= 0); |
| 158 | /* Wakeup only one waiting writer */ |
| 159 | if (!lock->reader) { |
| 160 | qemu_co_queue_next(&lock->queue); |
| 161 | } |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | void qemu_co_rwlock_wrlock(CoRwlock *lock) |
| 166 | { |
| 167 | while (lock->writer || lock->reader) { |
| 168 | qemu_co_queue_wait(&lock->queue); |
| 169 | } |
| 170 | lock->writer = true; |
| 171 | } |