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 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 static void qio_task_free(QIOTask *task) 74 { 75 qemu_mutex_lock(&task->thread_lock); 76 if (task->thread) { 77 if (task->thread->destroy) { 78 task->thread->destroy(task->thread->opaque); 79 } 80 81 if (task->thread->context) { 82 g_main_context_unref(task->thread->context); 83 } 84 85 g_free(task->thread); 86 } 87 88 if (task->destroy) { 89 task->destroy(task->opaque); 90 } 91 if (task->destroyResult) { 92 task->destroyResult(task->result); 93 } 94 if (task->err) { 95 error_free(task->err); 96 } 97 object_unref(task->source); 98 99 qemu_mutex_unlock(&task->thread_lock); 100 qemu_mutex_destroy(&task->thread_lock); 101 qemu_cond_destroy(&task->thread_cond); 102 103 g_free(task); 104 } 105 106 107 static gboolean qio_task_thread_result(gpointer opaque) 108 { 109 QIOTask *task = opaque; 110 111 trace_qio_task_thread_result(task); 112 qio_task_complete(task); 113 114 return FALSE; 115 } 116 117 118 static gpointer qio_task_thread_worker(gpointer opaque) 119 { 120 QIOTask *task = opaque; 121 122 trace_qio_task_thread_run(task); 123 124 task->thread->worker(task, task->thread->opaque); 125 126 /* We're running in the background thread, and must only 127 * ever report the task results in the main event loop 128 * thread. So we schedule an idle callback to report 129 * the worker results 130 */ 131 trace_qio_task_thread_exit(task); 132 133 qemu_mutex_lock(&task->thread_lock); 134 135 task->thread->completion = g_idle_source_new(); 136 g_source_set_callback(task->thread->completion, 137 qio_task_thread_result, task, NULL); 138 g_source_attach(task->thread->completion, 139 task->thread->context); 140 g_source_unref(task->thread->completion); 141 trace_qio_task_thread_source_attach(task, task->thread->completion); 142 143 qemu_cond_signal(&task->thread_cond); 144 qemu_mutex_unlock(&task->thread_lock); 145 146 return NULL; 147 } 148 149 150 void qio_task_run_in_thread(QIOTask *task, 151 QIOTaskWorker worker, 152 gpointer opaque, 153 GDestroyNotify destroy, 154 GMainContext *context) 155 { 156 struct QIOTaskThreadData *data = g_new0(struct QIOTaskThreadData, 1); 157 QemuThread thread; 158 159 if (context) { 160 g_main_context_ref(context); 161 } 162 163 data->worker = worker; 164 data->opaque = opaque; 165 data->destroy = destroy; 166 data->context = context; 167 168 task->thread = data; 169 170 trace_qio_task_thread_start(task, worker, opaque); 171 qemu_thread_create(&thread, 172 "io-task-worker", 173 qio_task_thread_worker, 174 task, 175 QEMU_THREAD_DETACHED); 176 } 177 178 179 void qio_task_wait_thread(QIOTask *task) 180 { 181 qemu_mutex_lock(&task->thread_lock); 182 g_assert(task->thread != NULL); 183 while (task->thread->completion == NULL) { 184 qemu_cond_wait(&task->thread_cond, &task->thread_lock); 185 } 186 187 trace_qio_task_thread_source_cancel(task, task->thread->completion); 188 g_source_destroy(task->thread->completion); 189 qemu_mutex_unlock(&task->thread_lock); 190 191 qio_task_thread_result(task); 192 } 193 194 195 void qio_task_complete(QIOTask *task) 196 { 197 task->func(task, task->opaque); 198 trace_qio_task_complete(task); 199 qio_task_free(task); 200 } 201 202 203 void qio_task_set_error(QIOTask *task, 204 Error *err) 205 { 206 error_propagate(&task->err, err); 207 } 208 209 210 bool qio_task_propagate_error(QIOTask *task, 211 Error **errp) 212 { 213 if (task->err) { 214 error_propagate(errp, task->err); 215 task->err = NULL; 216 return true; 217 } 218 219 return false; 220 } 221 222 223 void qio_task_set_result_pointer(QIOTask *task, 224 gpointer result, 225 GDestroyNotify destroy) 226 { 227 task->result = result; 228 task->destroyResult = destroy; 229 } 230 231 232 gpointer qio_task_get_result_pointer(QIOTask *task) 233 { 234 return task->result; 235 } 236 237 238 Object *qio_task_get_source(QIOTask *task) 239 { 240 return task->source; 241 } 242