usb-bus: introduce a wrapper function to check speed

In this way, we can check speed directly, don't need
call usb_device_attach(), which has other conditions,
such as checking the chardev is open.
Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb/bus.c

@@ -478,7 +478,7 @@ static void usb_mask_to_str(char *dest, size_t size,
     }
 }
 
-void usb_device_attach(USBDevice *dev, Error **errp)
+void usb_check_attach(USBDevice *dev, Error **errp)
 {
     USBBus *bus = usb_bus_from_device(dev);
     USBPort *port = dev->port;
@@ -499,6 +499,18 @@ void usb_device_attach(USBDevice *dev, Error **errp)
                    bus->qbus.name, port->path, portspeed);
         return;
     }
+}
+
+void usb_device_attach(USBDevice *dev, Error **errp)
+{
+    USBPort *port = dev->port;
+    Error *local_err = NULL;
+
+    usb_check_attach(dev, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
 
     dev->attached++;
     usb_attach(port);

include/hw/usb.h

@@ -553,6 +553,7 @@ void usb_release_port(USBDevice *dev);
 void usb_device_attach(USBDevice *dev, Error **errp);
 int usb_device_detach(USBDevice *dev);
 int usb_device_delete_addr(int busnr, int addr);
+void usb_check_attach(USBDevice *dev, Error **errp);
 
 static inline USBBus *usb_bus_from_device(USBDevice *d)
 {