io/task.c

   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 "trace.h"
  26
  27 struct QIOTask {
  28     Object *source;
  29     QIOTaskFunc func;
  30     gpointer opaque;
  31     GDestroyNotify destroy;
  32     Error *err;
  33     gpointer result;
  34     GDestroyNotify destroyResult;
  35 };
  36
  37
  38 QIOTask *qio_task_new(Object *source,
  39                       QIOTaskFunc func,
  40                       gpointer opaque,
  41                       GDestroyNotify destroy)
  42 {
  43     QIOTask *task;
  44
  45     task = g_new0(QIOTask, 1);
  46
  47     task->source = source;
  48     object_ref(source);
  49     task->func = func;
  50     task->opaque = opaque;
  51     task->destroy = destroy;
  52
  53     trace_qio_task_new(task, source, func, opaque);
  54
  55     return task;
  56 }
  57
  58 static void qio_task_free(QIOTask *task)
  59 {
  60     if (task->destroy) {
  61         task->destroy(task->opaque);
  62     }
  63     if (task->destroyResult) {
  64         task->destroyResult(task->result);
  65     }
  66     if (task->err) {
  67         error_free(task->err);
  68     }
  69     object_unref(task->source);
  70
  71     g_free(task);
  72 }
  73
  74
  75 struct QIOTaskThreadData {
  76     QIOTask *task;
  77     QIOTaskWorker worker;
  78     gpointer opaque;
  79     GDestroyNotify destroy;
  80 };
  81
  82
  83 static gboolean gio_task_thread_result(gpointer opaque)
  84 {
  85     struct QIOTaskThreadData *data = opaque;
  86
  87     trace_qio_task_thread_result(data->task);
  88     qio_task_complete(data->task);
  89
  90     if (data->destroy) {
  91         data->destroy(data->opaque);
  92     }
  93
  94     g_free(data);
  95
  96     return FALSE;
  97 }
  98
  99
 100 static gpointer qio_task_thread_worker(gpointer opaque)
 101 {
 102     struct QIOTaskThreadData *data = opaque;
 103
 104     trace_qio_task_thread_run(data->task);
 105     data->worker(data->task, data->opaque);
 106
 107     /* We're running in the background thread, and must only
 108      * ever report the task results in the main event loop
 109      * thread. So we schedule an idle callback to report
 110      * the worker results
 111      */
 112     trace_qio_task_thread_exit(data->task);
 113     g_idle_add(gio_task_thread_result, data);
 114     return NULL;
 115 }
 116
 117
 118 void qio_task_run_in_thread(QIOTask *task,
 119                             QIOTaskWorker worker,
 120                             gpointer opaque,
 121                             GDestroyNotify destroy)
 122 {
 123     struct QIOTaskThreadData *data = g_new0(struct QIOTaskThreadData, 1);
 124     QemuThread thread;
 125
 126     data->task = task;
 127     data->worker = worker;
 128     data->opaque = opaque;
 129     data->destroy = destroy;
 130
 131     trace_qio_task_thread_start(task, worker, opaque);
 132     qemu_thread_create(&thread,
 133                        "io-task-worker",
 134                        qio_task_thread_worker,
 135                        data,
 136                        QEMU_THREAD_DETACHED);
 137 }
 138
 139
 140 void qio_task_complete(QIOTask *task)
 141 {
 142     task->func(task, task->opaque);
 143     trace_qio_task_complete(task);
 144     qio_task_free(task);
 145 }
 146
 147
 148 void qio_task_set_error(QIOTask *task,
 149                         Error *err)
 150 {
 151     error_propagate(&task->err, err);
 152 }
 153
 154
 155 bool qio_task_propagate_error(QIOTask *task,
 156                               Error **errp)
 157 {
 158     if (task->err) {
 159         error_propagate(errp, task->err);
 160         task->err = NULL;
 161         return true;
 162     }
 163
 164     return false;
 165 }
 166
 167
 168 void qio_task_set_result_pointer(QIOTask *task,
 169                                  gpointer result,
 170                                  GDestroyNotify destroy)
 171 {
 172     task->result = result;
 173     task->destroyResult = destroy;
 174 }
 175
 176
 177 gpointer qio_task_get_result_pointer(QIOTask *task)
 178 {
 179     return task->result;
 180 }
 181
 182
 183 Object *qio_task_get_source(QIOTask *task)
 184 {
 185     return task->source;
 186 }