qdev: Create qdev_get_device_class() function

Extract the DeviceClass lookup from qdev_device_add() to a separate
function.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NAndreas Färber <afaerber@suse.de>

qdev-monitor.c

@@ -180,6 +180,44 @@ static const char *find_typename_by_alias(const char *alias)
     return NULL;
 }
 
+static DeviceClass *qdev_get_device_class(const char **driver, Error **errp)
+{
+    ObjectClass *oc;
+    DeviceClass *dc;
+
+    oc = object_class_by_name(*driver);
+    if (!oc) {
+        const char *typename = find_typename_by_alias(*driver);
+
+        if (typename) {
+            *driver = typename;
+            oc = object_class_by_name(*driver);
+        }
+    }
+
+    if (!object_class_dynamic_cast(oc, TYPE_DEVICE)) {
+        error_setg(errp, "'%s' is not a valid device model name", *driver);
+        return NULL;
+    }
+
+    if (object_class_is_abstract(oc)) {
+        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "driver",
+                  "non-abstract device type");
+        return NULL;
+    }
+
+    dc = DEVICE_CLASS(oc);
+    if (dc->cannot_instantiate_with_device_add_yet ||
+        (qdev_hotplug && !dc->hotpluggable)) {
+        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "driver",
+                  "pluggable device type");
+        return NULL;
+    }
+
+    return dc;
+}
+
+
 int qdev_device_help(QemuOpts *opts)
 {
     Error *local_err = NULL;
@@ -455,7 +493,6 @@ static BusState *qbus_find(const char *path)
 
 DeviceState *qdev_device_add(QemuOpts *opts)
 {
-    ObjectClass *oc;
     DeviceClass *dc;
     const char *driver, *path, *id;
     DeviceState *dev;
@@ -469,33 +506,10 @@ DeviceState *qdev_device_add(QemuOpts *opts)
     }
 
     /* find driver */
-    oc = object_class_by_name(driver);
-    if (!oc) {
-        const char *typename = find_typename_by_alias(driver);
-
-        if (typename) {
-            driver = typename;
-            oc = object_class_by_name(driver);
-        }
-    }
-
-    if (!object_class_dynamic_cast(oc, TYPE_DEVICE)) {
-        qerror_report(ERROR_CLASS_GENERIC_ERROR,
-                      "'%s' is not a valid device model name", driver);
-        return NULL;
-    }
-
-    if (object_class_is_abstract(oc)) {
-        qerror_report(QERR_INVALID_PARAMETER_VALUE, "driver",
-                      "non-abstract device type");
-        return NULL;
-    }
-
-    dc = DEVICE_CLASS(oc);
-    if (dc->cannot_instantiate_with_device_add_yet ||
-        (qdev_hotplug && !dc->hotpluggable)) {
-        qerror_report(QERR_INVALID_PARAMETER_VALUE, "driver",
-                      "pluggable device type");
+    dc = qdev_get_device_class(&driver, &err);
+    if (err) {
+        qerror_report_err(err);
+        error_free(err);
         return NULL;
     }