From 9561fda8d90e176bef598ba87c42a1bd6ad03ef7 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 19 Mar 2014 08:58:55 +0100 Subject: qom: Make QOM link property unref optional MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some object_property_add_link() callers expect property deletion to unref the link property object. Other callers expect to manage the refcount themselves. The former are currently broken and therefore leak the link property object. This patch adds a flags argument to object_property_add_link() so the caller can specify which refcount behavior they require. The new OBJ_PROP_LINK_UNREF_ON_RELEASE flag causes the link pointer to be unreferenced when the property is deleted. This fixes refcount leaks in qdev.c, xilinx_axidma.c, xilinx_axienet.c, s390-virtio-bus.c, virtio-pci.c, virtio-rng.c, and ui/console.c. Rationale for refcount behavior: * hw/core/qdev.c - bus children are explicitly unreferenced, don't interfere - parent_bus is essentially a read-only property that doesn't hold a refcount, don't unref - hotplug_handler is leaked, do unref * hw/dma/xilinx_axidma.c - rx stream "dma" links are set using set_link, therefore they need unref - tx streams are set using set_link, therefore they need unref * hw/net/xilinx_axienet.c - same reasoning as hw/dma/xilinx_axidma.c * hw/pcmcia/pxa2xx.c - pxa2xx bypasses set_link and therefore does not use refcounts * hw/s390x/s390-virtio-bus.c * hw/virtio/virtio-pci.c * hw/virtio/virtio-rng.c * ui/console.c - set_link is used and there is no explicit unref, do unref Cc: Peter Crosthwaite Cc: Alexander Graf Cc: Anthony Liguori Cc: "Michael S. Tsirkin" Signed-off-by: Stefan Hajnoczi Reviewed-by: Paolo Bonzini Signed-off-by: Andreas Färber --- include/qom/object.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'include/qom') diff --git a/include/qom/object.h b/include/qom/object.h index 4cd77049e4..9feb441986 100644 --- a/include/qom/object.h +++ b/include/qom/object.h @@ -1067,12 +1067,18 @@ Object *object_resolve_path_component(Object *parent, const gchar *part); void object_property_add_child(Object *obj, const char *name, Object *child, Error **errp); +typedef enum { + /* Unref the link pointer when the property is deleted */ + OBJ_PROP_LINK_UNREF_ON_RELEASE = 0x1, +} ObjectPropertyLinkFlags; + /** * object_property_add_link: * @obj: the object to add a property to * @name: the name of the property * @type: the qobj type of the link * @child: a pointer to where the link object reference is stored + * @flags: additional options for the link * @errp: if an error occurs, a pointer to an area to store the area * * Links establish relationships between objects. Links are unidirectional @@ -1084,10 +1090,13 @@ void object_property_add_child(Object *obj, const char *name, * Ownership of the pointer that @child points to is transferred to the * link property. The reference count for *@child is * managed by the property from after the function returns till the - * property is deleted with object_property_del(). + * property is deleted with object_property_del(). If the + * @flags OBJ_PROP_LINK_UNREF_ON_RELEASE bit is set, + * the reference count is decremented when the property is deleted. */ void object_property_add_link(Object *obj, const char *name, const char *type, Object **child, + ObjectPropertyLinkFlags flags, Error **errp); /** -- cgit v1.2.3