[Qemu-devel] [RFC 4/4] qdev: Make subclasses inherit properties from superclass

[Eduardo Habkost <ehabkost@redhat.com>]

Instead of scanning all parent classes every time we walk the list of
properties, just make DeviceState subclasses inherit the property list
from the parent class.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 hw/core/qdev-properties.c | 15 +--------------
 hw/core/qdev.c            | 42 +++++++++++++++---------------------------
 qdev-monitor.c            |  7 +------
 qmp.c                     | 47 ++++++++++++++++++++++-------------------------
 4 files changed, 39 insertions(+), 72 deletions(-)

diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index d506793..d685d72 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -836,20 +836,7 @@ static Property *qdev_prop_walk(GList *props, const char *name)
 
 static Property *qdev_prop_find(DeviceState *dev, const char *name)
 {
-    ObjectClass *class;
-    Property *prop;
-
-    /* device properties */
-    class = object_get_class(OBJECT(dev));
-    do {
-        prop = qdev_prop_walk(DEVICE_CLASS(class)->props, name);
-        if (prop) {
-            return prop;
-        }
-        class = object_class_get_parent(class);
-    } while (class != object_class_by_name(TYPE_DEVICE));
-
-    return NULL;
+    return qdev_prop_walk(DEVICE_GET_CLASS(dev)->props, name);
 }
 
 void error_set_from_qdev_prop_error(Error **errp, int ret, DeviceState *dev,
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index b549ae6..bc26b32 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -919,21 +919,14 @@ void qdev_property_add_static(DeviceState *dev, Property *prop,
  */
 void qdev_alias_all_properties(DeviceState *target, Object *source)
 {
-    ObjectClass *class;
     GList *props;
 
-    class = object_get_class(OBJECT(target));
-    do {
-        DeviceClass *dc = DEVICE_CLASS(class);
-
-        for (props = dc->props; props; props = props->next) {
-            Property *prop = props->data;
-            object_property_add_alias(source, prop->name,
-                                      OBJECT(target), prop->name,
-                                      &error_abort);
-        }
-        class = object_class_get_parent(class);
-    } while (class != object_class_by_name(TYPE_DEVICE));
+    for (props = DEVICE_GET_CLASS(target)->props; props; props = props->next) {
+        Property *prop = props->data;
+        object_property_add_alias(source, prop->name,
+                                  OBJECT(target), prop->name,
+                                  &error_abort);
+    }
 }
 
 int qdev_build_hotpluggable_device_list(Object *obj, void *opaque)
@@ -1083,7 +1076,7 @@ static void device_set_hotplugged(Object *obj, bool value, Error **err)
 static void device_initfn(Object *obj)
 {
     DeviceState *dev = DEVICE(obj);
-    ObjectClass *class;
+    GList *props;
 
     if (qdev_hotplug) {
         dev->hotplugged = 1;
@@ -1101,16 +1094,11 @@ static void device_initfn(Object *obj)
                              device_get_hotplugged, device_set_hotplugged,
                              &error_abort);
 
-    class = object_get_class(OBJECT(dev));
-    do {
-        GList *props;
-        for (props = DEVICE_CLASS(class)->props; props; props = props->next) {
-            Property *prop = props->data;
-            qdev_property_add_legacy(dev, prop, &error_abort);
-            qdev_property_add_static(dev, prop, &error_abort);
-        }
-        class = object_class_get_parent(class);
-    } while (class != object_class_by_name(TYPE_DEVICE));
+    for (props = DEVICE_GET_CLASS(dev)->props; props; props = props->next) {
+        Property *prop = props->data;
+        qdev_property_add_legacy(dev, prop, &error_abort);
+        qdev_property_add_static(dev, prop, &error_abort);
+    }
 
     object_property_add_link(OBJECT(dev), "parent_bus", TYPE_BUS,
                              (Object **)&dev->parent_bus, NULL, 0,
@@ -1169,10 +1157,10 @@ static void device_class_base_init(ObjectClass *class, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(class);
 
-    /* We explicitly look up properties in the superclasses,
-     * so do not propagate them to the subclasses.
+    /* We inherit properties from the superclass, but we need to fix the
+     * list pointer that was memcpy()ed.
      */
-    dc->props = NULL;
+    dc->props = g_list_copy(dc->props);
 }
 
 static void device_unparent(Object *obj)
diff --git a/qdev-monitor.c b/qdev-monitor.c
index d151dfd..2d5e9f7 100644
--- a/qdev-monitor.c
+++ b/qdev-monitor.c
@@ -624,7 +624,6 @@ static void bus_print_dev(BusState *bus, Monitor *mon, DeviceState *dev, int ind
 
 static void qdev_print(Monitor *mon, DeviceState *dev, int indent)
 {
-    ObjectClass *class;
     BusState *child;
     NamedGPIOList *ngl;
 
@@ -641,11 +640,7 @@ static void qdev_print(Monitor *mon, DeviceState *dev, int indent)
                         ngl->num_out);
         }
     }
-    class = object_get_class(OBJECT(dev));
-    do {
-        qdev_print_props(mon, dev, DEVICE_CLASS(class)->props, indent);
-        class = object_class_get_parent(class);
-    } while (class != object_class_by_name(TYPE_DEVICE));
+    qdev_print_props(mon, dev, DEVICE_GET_CLASS(dev)->props, indent);
     bus_print_dev(dev->parent_bus, mon, dev, indent);
     QLIST_FOREACH(child, &dev->child_bus, sibling) {
         qbus_print(mon, child, indent);
diff --git a/qmp.c b/qmp.c
index 7d91a18..ea32d27 100644
--- a/qmp.c
+++ b/qmp.c
@@ -446,34 +446,31 @@ static DevicePropertyInfo *make_device_property_info(ObjectClass *klass,
                                                      const char *description)
 {
     DevicePropertyInfo *info;
+    GList *props;
 
-    do {
-        GList *props;
-        for (props = DEVICE_CLASS(klass)->props; props; props = props->next) {
-            Property *prop = props->data;
-            if (strcmp(name, prop->name) != 0) {
-                continue;
-            }
-
-            /*
-             * TODO Properties without a parser are just for dirty hacks.
-             * qdev_prop_ptr is the only such PropertyInfo.  It's marked
-             * for removal.  This conditional should be removed along with
-             * it.
-             */
-            if (!prop->info->set) {
-                return NULL;           /* no way to set it, don't show */
-            }
+    for (props = DEVICE_CLASS(klass)->props; props; props = props->next) {
+        Property *prop = props->data;
+        if (strcmp(name, prop->name) != 0) {
+            continue;
+        }
 
-            info = g_malloc0(sizeof(*info));
-            info->name = g_strdup(prop->name);
-            info->type = g_strdup(prop->info->name);
-            info->has_description = !!prop->info->description;
-            info->description = g_strdup(prop->info->description);
-            return info;
+        /*
+         * TODO Properties without a parser are just for dirty hacks.
+         * qdev_prop_ptr is the only such PropertyInfo.  It's marked
+         * for removal.  This conditional should be removed along with
+         * it.
+         */
+        if (!prop->info->set) {
+            return NULL;           /* no way to set it, don't show */
         }
-        klass = object_class_get_parent(klass);
-    } while (klass != object_class_by_name(TYPE_DEVICE));
+
+        info = g_malloc0(sizeof(*info));
+        info->name = g_strdup(prop->name);
+        info->type = g_strdup(prop->info->name);
+        info->has_description = !!prop->info->description;
+        info->description = g_strdup(prop->info->description);
+        return info;
+    }
 
     /* Not a qdev property, use the default type */
     info = g_malloc0(sizeof(*info));
-- 
1.9.3