usbnet: runtime wake up device before calling usbnet_{read|write}_cmd

This patch gets the runtime PM reference count before calling
usbnet_{read|write}_cmd, and puts it after completion of the
usbnet_{read|write}_cmd, so that the usb control message can always
be sent to one active device in the non-PM context.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/usbnet.c

@@ -1670,8 +1670,14 @@ static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
 		    u16 value, u16 index, void *data, u16 size)
 {
-	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
-				 data, size);
+	int ret;
+
+	if (usb_autopm_get_interface(dev->intf) < 0)
+		return -ENODEV;
+	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
+				data, size);
+	usb_autopm_put_interface(dev->intf);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
 
@@ -1682,8 +1688,14 @@ EXPORT_SYMBOL_GPL(usbnet_read_cmd);
 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
 		     u16 value, u16 index, const void *data, u16 size)
 {
-	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
-				  data, size);
+	int ret;
+
+	if (usb_autopm_get_interface(dev->intf) < 0)
+		return -ENODEV;
+	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
+				 data, size);
+	usb_autopm_put_interface(dev->intf);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(usbnet_write_cmd);