[Qemu-devel] [PATCH v2] virtio: link the rng backend through an alias property

[Paolo Bonzini <pbonzini@redhat.com>]

The virtio-rng backend is currently linked twice, once in the proxy
device (e.g. virtio-rng-pci) and once in virtio-rng-device.  This causes
a double unref of the backend when the parent device is unplugged.

To fix this, make the proxy device use an alias, similar to what is
already being done for the iothread link.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

---
v1->v2: also change s390-virtio-bus.c (Gonglei)
---
 hw/s390x/s390-virtio-bus.c | 6 ++----
 hw/s390x/virtio-ccw.c      | 6 ++----
 hw/virtio/virtio-pci.c     | 7 ++-----
 3 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
index 2059874..39dc201 100644
--- a/hw/s390x/s390-virtio-bus.c
+++ b/hw/s390x/s390-virtio-bus.c
@@ -311,10 +311,8 @@ static void s390_virtio_rng_instance_init(Object *obj)
 
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VIRTIO_RNG);
-    object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
-                             (Object **)&dev->vdev.conf.rng,
-                             qdev_prop_allow_set_link_before_realize,
-                             OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL);
+    object_property_add_alias(obj, "rng", OBJECT(&dev->vdev),
+                              "rng", &error_abort);
 }
 
 static uint64_t s390_virtio_device_vq_token(VirtIOS390Device *dev, int vq)
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 1c0d913..ea236c9 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -1544,10 +1544,8 @@ static void virtio_ccw_rng_instance_init(Object *obj)
 
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VIRTIO_RNG);
-    object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
-                             (Object **)&dev->vdev.conf.rng,
-                             qdev_prop_allow_set_link_before_realize,
-                             OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL);
+    object_property_add_alias(obj, "rng", OBJECT(&dev->vdev),
+                              "rng", &error_abort);
 }
 
 static Property virtio_ccw_rng_properties[] = {
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 542fb9e..e490ade 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1525,11 +1525,8 @@ static void virtio_rng_initfn(Object *obj)
 
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VIRTIO_RNG);
-    object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
-                             (Object **)&dev->vdev.conf.rng,
-                             qdev_prop_allow_set_link_before_realize,
-                             OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL);
-
+    object_property_add_alias(obj, "rng", OBJECT(&dev->vdev), "rng",
+                              &error_abort);
 }
 
 static const TypeInfo virtio_rng_pci_info = {
-- 
1.8.3.1