[PULL,04/17] hw/virtio: Use object_initialize_child for correct reference counting
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Message ID 20190524184447.16678-5-ehabkost@redhat.com
State New
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Series
  • [PULL,01/17] qom/object: Display more helpful message when an object type is missing
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Commit Message

Eduardo Habkost May 24, 2019, 6:44 p.m. UTC
From: Philippe Mathieu-Daudé <philmd@redhat.com>

As explained in commit aff39be0ed97:

  Both functions, object_initialize() and object_property_add_child()
  increase the reference counter of the new object, so one of the
  references has to be dropped afterwards to get the reference
  counting right. Otherwise the child object will not be properly
  cleaned up when the parent gets destroyed.
  Thus let's use now object_initialize_child() instead to get the
  reference counting here right.

This patch was generated using the following Coccinelle script:

 @use_object_initialize_child@
 expression parent_obj;
 expression child_ptr;
 expression child_name;
 expression child_type;
 expression child_size;
 expression errp;
 @@
 (
 -   object_initialize(child_ptr, child_size, child_type);
 +   object_initialize_child(parent_obj, child_name,  child_ptr, child_size,
 +                           child_type, &error_abort, NULL);
     ... when != parent_obj
 -   object_property_add_child(parent_obj, child_name, OBJECT(child_ptr), NULL);
     ...
 ?-  object_unref(OBJECT(child_ptr));
 |
 -   object_initialize(child_ptr, child_size, child_type);
 +   object_initialize_child(parent_obj, child_name,  child_ptr, child_size,
 +                            child_type, errp, NULL);
     ... when != parent_obj
 -   object_property_add_child(parent_obj, child_name, OBJECT(child_ptr), errp);
     ...
 ?-  object_unref(OBJECT(child_ptr));
 )

While the object_initialize() function doesn't take an
'Error *errp' argument, the object_initialize_child() does.
Since this code is used when a machine is created (and is not
yet running), we deliberately choose to use the &error_abort
argument instead of ignoring errors if an object creation failed.

Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Inspired-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190507163416.24647-4-philmd@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 hw/virtio/virtio.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Patch
diff mbox series

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 4805727b53..07f4a64b48 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2312,9 +2312,8 @@  void virtio_instance_init_common(Object *proxy_obj, void *data,
 {
     DeviceState *vdev = data;
 
-    object_initialize(vdev, vdev_size, vdev_name);
-    object_property_add_child(proxy_obj, "virtio-backend", OBJECT(vdev), NULL);
-    object_unref(OBJECT(vdev));
+    object_initialize_child(proxy_obj, "virtio-backend", vdev, vdev_size,
+                            vdev_name, &error_abort, NULL);
     qdev_alias_all_properties(vdev, proxy_obj);
 }