qdev: Factor qdev_create_from_info() out of qdev_create()

To make it obvious that -device and device_add can't die in
hw_error().

hw/qdev.c

@@ -78,13 +78,32 @@ static DeviceInfo *qdev_find_info(BusInfo *bus_info, const char *name)
     return NULL;
 }
 
+static DeviceState *qdev_create_from_info(BusState *bus, DeviceInfo *info)
+{
+    DeviceState *dev;
+
+    assert(bus->info == info->bus_info);
+    dev = qemu_mallocz(info->size);
+    dev->info = info;
+    dev->parent_bus = bus;
+    qdev_prop_set_defaults(dev, dev->info->props);
+    qdev_prop_set_defaults(dev, dev->parent_bus->info->props);
+    qdev_prop_set_globals(dev);
+    QLIST_INSERT_HEAD(&bus->children, dev, sibling);
+    if (qdev_hotplug) {
+        assert(bus->allow_hotplug);
+        dev->hotplugged = 1;
+    }
+    dev->state = DEV_STATE_CREATED;
+    return dev;
+}
+
 /* Create a new device.  This only initializes the device state structure
    and allows properties to be set.  qdev_init should be called to
    initialize the actual device emulation.  */
 DeviceState *qdev_create(BusState *bus, const char *name)
 {
     DeviceInfo *info;
-    DeviceState *dev;
 
     if (!bus) {
         if (!main_system_bus) {
@@ -98,19 +117,7 @@ DeviceState *qdev_create(BusState *bus, const char *name)
         hw_error("Unknown device '%s' for bus '%s'\n", name, bus->info->name);
     }
 
-    dev = qemu_mallocz(info->size);
-    dev->info = info;
-    dev->parent_bus = bus;
-    qdev_prop_set_defaults(dev, dev->info->props);
-    qdev_prop_set_defaults(dev, dev->parent_bus->info->props);
-    qdev_prop_set_globals(dev);
-    QLIST_INSERT_HEAD(&bus->children, dev, sibling);
-    if (qdev_hotplug) {
-        assert(bus->allow_hotplug);
-        dev->hotplugged = 1;
-    }
-    dev->state = DEV_STATE_CREATED;
-    return dev;
+    return qdev_create_from_info(bus, info);
 }
 
 static void qdev_print_devinfo(DeviceInfo *info)
@@ -224,7 +231,7 @@ DeviceState *qdev_device_add(QemuOpts *opts)
     }
 
     /* create device, set properties */
-    qdev = qdev_create(bus, driver);
+    qdev = qdev_create_from_info(bus, info);
     id = qemu_opts_id(opts);
     if (id) {
         qdev->id = id;