| 1 | /* |
| 2 | * QEMU I/O task |
| 3 | * |
| 4 | * Copyright (c) 2015 Red Hat, Inc. |
| 5 | * |
| 6 | * This library is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public |
| 8 | * License as published by the Free Software Foundation; either |
| 9 | * version 2.1 of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * This library is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public |
| 17 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
| 18 | * |
| 19 | */ |
| 20 | |
| 21 | #include "qemu/osdep.h" |
| 22 | #include "io/task.h" |
| 23 | #include "qapi/error.h" |
| 24 | #include "qemu/thread.h" |
| 25 | #include "qom/object.h" |
| 26 | #include "trace.h" |
| 27 | |
| 28 | struct QIOTaskThreadData { |
| 29 | QIOTaskWorker worker; |
| 30 | gpointer opaque; |
| 31 | GDestroyNotify destroy; |
| 32 | GMainContext *context; |
| 33 | GSource *completion; |
| 34 | }; |
| 35 | |
| 36 | |
| 37 | struct QIOTask { |
| 38 | Object *source; |
| 39 | QIOTaskFunc func; |
| 40 | gpointer opaque; |
| 41 | GDestroyNotify destroy; |
| 42 | Error *err; |
| 43 | gpointer result; |
| 44 | GDestroyNotify destroyResult; |
| 45 | QemuMutex thread_lock; |
| 46 | QemuCond thread_cond; |
| 47 | struct QIOTaskThreadData *thread; |
| 48 | }; |
| 49 | |
| 50 | |
| 51 | QIOTask *qio_task_new(Object *source, |
| 52 | QIOTaskFunc func, |
| 53 | gpointer opaque, |
| 54 | GDestroyNotify destroy) |
| 55 | { |
| 56 | QIOTask *task; |
| 57 | |
| 58 | task = g_new0(QIOTask, 1); |
| 59 | |
| 60 | task->source = source; |
| 61 | object_ref(source); |
| 62 | task->func = func; |
| 63 | task->opaque = opaque; |
| 64 | task->destroy = destroy; |
| 65 | qemu_mutex_init(&task->thread_lock); |
| 66 | qemu_cond_init(&task->thread_cond); |
| 67 | |
| 68 | trace_qio_task_new(task, source, func, opaque); |
| 69 | |
| 70 | return task; |
| 71 | } |
| 72 | |
| 73 | void qio_task_free(QIOTask *task) |
| 74 | { |
| 75 | if (!task) { |
| 76 | return; |
| 77 | } |
| 78 | |
| 79 | qemu_mutex_lock(&task->thread_lock); |
| 80 | if (task->thread) { |
| 81 | if (task->thread->destroy) { |
| 82 | task->thread->destroy(task->thread->opaque); |
| 83 | } |
| 84 | |
| 85 | if (task->thread->context) { |
| 86 | g_main_context_unref(task->thread->context); |
| 87 | } |
| 88 | |
| 89 | g_free(task->thread); |
| 90 | } |
| 91 | |
| 92 | if (task->destroy) { |
| 93 | task->destroy(task->opaque); |
| 94 | } |
| 95 | if (task->destroyResult) { |
| 96 | task->destroyResult(task->result); |
| 97 | } |
| 98 | error_free(task->err); |
| 99 | object_unref(task->source); |
| 100 | |
| 101 | qemu_mutex_unlock(&task->thread_lock); |
| 102 | qemu_mutex_destroy(&task->thread_lock); |
| 103 | qemu_cond_destroy(&task->thread_cond); |
| 104 | |
| 105 | g_free(task); |
| 106 | } |
| 107 | |
| 108 | |
| 109 | static gboolean qio_task_thread_result(gpointer opaque) |
| 110 | { |
| 111 | QIOTask *task = opaque; |
| 112 | |
| 113 | trace_qio_task_thread_result(task); |
| 114 | qio_task_complete(task); |
| 115 | qio_task_free(task); |
| 116 | |
| 117 | return FALSE; |
| 118 | } |
| 119 | |
| 120 | |
| 121 | static gpointer qio_task_thread_worker(gpointer opaque) |
| 122 | { |
| 123 | QIOTask *task = opaque; |
| 124 | |
| 125 | trace_qio_task_thread_run(task); |
| 126 | |
| 127 | task->thread->worker(task, task->thread->opaque); |
| 128 | |
| 129 | /* We're running in the background thread, and must only |
| 130 | * ever report the task results in the main event loop |
| 131 | * thread. So we schedule an idle callback to report |
| 132 | * the worker results |
| 133 | */ |
| 134 | trace_qio_task_thread_exit(task); |
| 135 | |
| 136 | qemu_mutex_lock(&task->thread_lock); |
| 137 | |
| 138 | task->thread->completion = g_idle_source_new(); |
| 139 | g_source_set_callback(task->thread->completion, |
| 140 | qio_task_thread_result, task, NULL); |
| 141 | g_source_attach(task->thread->completion, |
| 142 | task->thread->context); |
| 143 | g_source_unref(task->thread->completion); |
| 144 | trace_qio_task_thread_source_attach(task, task->thread->completion); |
| 145 | |
| 146 | qemu_cond_signal(&task->thread_cond); |
| 147 | qemu_mutex_unlock(&task->thread_lock); |
| 148 | |
| 149 | return NULL; |
| 150 | } |
| 151 | |
| 152 | |
| 153 | void qio_task_run_in_thread(QIOTask *task, |
| 154 | QIOTaskWorker worker, |
| 155 | gpointer opaque, |
| 156 | GDestroyNotify destroy, |
| 157 | GMainContext *context) |
| 158 | { |
| 159 | struct QIOTaskThreadData *data = g_new0(struct QIOTaskThreadData, 1); |
| 160 | QemuThread thread; |
| 161 | |
| 162 | if (context) { |
| 163 | g_main_context_ref(context); |
| 164 | } |
| 165 | |
| 166 | data->worker = worker; |
| 167 | data->opaque = opaque; |
| 168 | data->destroy = destroy; |
| 169 | data->context = context; |
| 170 | |
| 171 | task->thread = data; |
| 172 | |
| 173 | trace_qio_task_thread_start(task, worker, opaque); |
| 174 | qemu_thread_create(&thread, |
| 175 | "io-task-worker", |
| 176 | qio_task_thread_worker, |
| 177 | task, |
| 178 | QEMU_THREAD_DETACHED); |
| 179 | } |
| 180 | |
| 181 | |
| 182 | void qio_task_wait_thread(QIOTask *task) |
| 183 | { |
| 184 | qemu_mutex_lock(&task->thread_lock); |
| 185 | g_assert(task->thread != NULL); |
| 186 | while (task->thread->completion == NULL) { |
| 187 | qemu_cond_wait(&task->thread_cond, &task->thread_lock); |
| 188 | } |
| 189 | |
| 190 | trace_qio_task_thread_source_cancel(task, task->thread->completion); |
| 191 | g_source_destroy(task->thread->completion); |
| 192 | qemu_mutex_unlock(&task->thread_lock); |
| 193 | |
| 194 | qio_task_thread_result(task); |
| 195 | } |
| 196 | |
| 197 | |
| 198 | void qio_task_complete(QIOTask *task) |
| 199 | { |
| 200 | task->func(task, task->opaque); |
| 201 | trace_qio_task_complete(task); |
| 202 | } |
| 203 | |
| 204 | |
| 205 | void qio_task_set_error(QIOTask *task, |
| 206 | Error *err) |
| 207 | { |
| 208 | error_propagate(&task->err, err); |
| 209 | } |
| 210 | |
| 211 | |
| 212 | bool qio_task_propagate_error(QIOTask *task, |
| 213 | Error **errp) |
| 214 | { |
| 215 | if (task->err) { |
| 216 | error_propagate(errp, task->err); |
| 217 | task->err = NULL; |
| 218 | return true; |
| 219 | } |
| 220 | |
| 221 | return false; |
| 222 | } |
| 223 | |
| 224 | |
| 225 | void qio_task_set_result_pointer(QIOTask *task, |
| 226 | gpointer result, |
| 227 | GDestroyNotify destroy) |
| 228 | { |
| 229 | task->result = result; |
| 230 | task->destroyResult = destroy; |
| 231 | } |
| 232 | |
| 233 | |
| 234 | gpointer qio_task_get_result_pointer(QIOTask *task) |
| 235 | { |
| 236 | return task->result; |
| 237 | } |
| 238 | |
| 239 | |
| 240 | Object *qio_task_get_source(QIOTask *task) |
| 241 | { |
| 242 | return task->source; |
| 243 | } |