qio: non-default context for threaded qtask

qio_task_run_in_thread() allows main thread to run blocking operations
in the background. However it has an assumption on that it's always
working with the default context. This patch tries to allow the threaded
QIO task framework to run with non-default gcontext.

Currently no functional change so far, so the QIOTasks are still always
running on main context.

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

1 files changed, 18 insertions, 2 deletions

diff --git a/io/task.c b/io/task.c
index 1a0a1c7185..2886a2c1bc 100644
--- a/io/task.c
+++ b/io/task.c
@@ -77,6 +77,7 @@ struct QIOTaskThreadData {
     QIOTaskWorker worker;
     gpointer opaque;
     GDestroyNotify destroy;
+    GMainContext *context;
 };
 
 
@@ -91,6 +92,10 @@ static gboolean qio_task_thread_result(gpointer opaque)
         data->destroy(data->opaque);
     }
 
+    if (data->context) {
+        g_main_context_unref(data->context);
+    }
+
     g_free(data);
 
     return FALSE;
@@ -100,6 +105,7 @@ static gboolean qio_task_thread_result(gpointer opaque)
 static gpointer qio_task_thread_worker(gpointer opaque)
 {
     struct QIOTaskThreadData *data = opaque;
+    GSource *idle;
 
     trace_qio_task_thread_run(data->task);
     data->worker(data->task, data->opaque);
@@ -110,7 +116,11 @@ static gpointer qio_task_thread_worker(gpointer opaque)
      * the worker results
      */
     trace_qio_task_thread_exit(data->task);
-    g_idle_add(qio_task_thread_result, data);
+
+    idle = g_idle_source_new();
+    g_source_set_callback(idle, qio_task_thread_result, data, NULL);
+    g_source_attach(idle, data->context);
+
     return NULL;
 }
 
@@ -118,15 +128,21 @@ static gpointer qio_task_thread_worker(gpointer opaque)
 void qio_task_run_in_thread(QIOTask *task,
                             QIOTaskWorker worker,
                             gpointer opaque,
-                            GDestroyNotify destroy)
+                            GDestroyNotify destroy,
+                            GMainContext *context)
 {
     struct QIOTaskThreadData *data = g_new0(struct QIOTaskThreadData, 1);
     QemuThread thread;
 
+    if (context) {
+        g_main_context_ref(context);
+    }
+
     data->task = task;
     data->worker = worker;
     data->opaque = opaque;
     data->destroy = destroy;
+    data->context = context;
 
     trace_qio_task_thread_start(task, worker, opaque);
     qemu_thread_create(&thread,