Re: [Qemu-devel] [PATCH 04/11] qdev: add reference count to a device for the BusChild

[Anthony Liguori <aliguori@us.ibm.com>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> Each device has a reference through the BusChild.  This reference
> was not accounted for, add it now.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  hw/qdev.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/hw/qdev.c b/hw/qdev.c
> index e758131..87dfcb5 100644
> --- a/hw/qdev.c
> +++ b/hw/qdev.c
> @@ -65,7 +65,10 @@ static void bus_remove_child(BusState *bus, DeviceState *child)
>  
>              snprintf(name, sizeof(name), "child[%d]", kid->index);
>              QTAILQ_REMOVE(&bus->children, kid, sibling);
> +
> +            /* This gives back ownership of kid->child back to us.  */
>              object_property_del(OBJECT(bus), name, NULL);
> +            object_unref(OBJECT(kid->child));
>              g_free(kid);
>              return;
>          }
> @@ -83,9 +86,11 @@ static void bus_add_child(BusState *bus, DeviceState *child)
>  
>      kid->index = bus->max_index++;
>      kid->child = child;
> +    object_ref(OBJECT(kid->child));
>  
>      QTAILQ_INSERT_HEAD(&bus->children, kid, sibling);
>  
> +    /* This transfers ownership of kid->child to the property.  */
>      snprintf(name, sizeof(name), "child[%d]", kid->index);
>      object_property_add_link(OBJECT(bus), name,
>                               object_get_typename(OBJECT(child)),


The link property itself holds a reference no?  Or is this not the case
because we aren't checking a link when it's added and taking a reference
if it's !NULL?

Regards,

Anthony Liguori

> -- 
> 1.8.0.1