[Qemu-devel] [PATCH 10/14] qio: refcount QIOTask

[Peter Xu <peterx@redhat.com>]

It will be used in multiple threads in follow-up patches.  Let it start
to have refcounts.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/io/task.h |  3 +++
 io/task.c         | 23 ++++++++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/include/io/task.h b/include/io/task.h
index 9dbe3758d7..c6acd6489c 100644
--- a/include/io/task.h
+++ b/include/io/task.h
@@ -322,4 +322,7 @@ gpointer qio_task_get_result_pointer(QIOTask *task);
  */
 Object *qio_task_get_source(QIOTask *task);
 
+void qio_task_ref(QIOTask *task);
+void qio_task_unref(QIOTask *task);
+
 #endif /* QIO_TASK_H */
diff --git a/io/task.c b/io/task.c
index 204c0be286..00d3a5096a 100644
--- a/io/task.c
+++ b/io/task.c
@@ -32,6 +32,7 @@ struct QIOTask {
     Error *err;
     gpointer result;
     GDestroyNotify destroyResult;
+    uint32_t refcount;
 
     /* Threaded QIO task specific fields */
     GSource *idle_source;  /* The idle task to run complete routine */
@@ -57,6 +58,8 @@ QIOTask *qio_task_new(Object *source,
 
     trace_qio_task_new(task, source, func, opaque);
 
+    qio_task_ref(task);
+
     return task;
 }
 
@@ -165,7 +168,7 @@ void qio_task_complete(QIOTask *task)
 {
     task->func(task, task->opaque);
     trace_qio_task_complete(task);
-    qio_task_free(task);
+    qio_task_unref(task);
 }
 
 
@@ -208,3 +211,21 @@ Object *qio_task_get_source(QIOTask *task)
 {
     return task->source;
 }
+
+void qio_task_ref(QIOTask *task)
+{
+    if (!task) {
+        return;
+    }
+    atomic_inc(&task->refcount);
+}
+
+void qio_task_unref(QIOTask *task)
+{
+    if (!task) {
+        return;
+    }
+    if (atomic_fetch_dec(&task->refcount) == 1) {
+        qio_task_free(task);
+    }
+}
-- 
2.14.3