2 files changed, 6 insertions, 2 deletions

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index df2749052e2c..390749bbb0c3 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -938,7 +938,7 @@ static int get_string(struct usb_composite_dev *cdev,
         else if (cdev->product_override == id)
                 str = iProduct ?: composite->iProduct;
         else if (cdev->serial_override == id)
-                str = iSerialNumber;
+                str = iSerialNumber ?: composite->iSerialNumber;
         else
                 str = NULL;
         if (str) {
@@ -1503,7 +1503,8 @@ static int composite_bind(struct usb_gadget *gadget)
                 cdev->product_override =
                         override_id(cdev, &cdev->desc.iProduct);
 
-        if (iSerialNumber)
+        if (iSerialNumber ||
+            (!cdev->desc.iSerialNumber && composite->iSerialNumber))
                 cdev->serial_override =
                         override_id(cdev, &cdev->desc.iSerialNumber);
 
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index 5d27a1fe5ce9..9d8c3b634493 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -253,6 +253,8 @@ void usb_remove_config(struct usb_composite_dev *,
  * @iManufacturer: Used as iManufacturer override if @dev->iManufacturer is
  *      not set. If NULL a default "<system> <release> with <udc>" value
  *      will be used.
+ * @iSerialNumber: Used as iSerialNumber override if @dev->iSerialNumber is
+ *      not set.
  * @dev: Template descriptor for the device, including default device
  *      identifiers.
  * @strings: tables of strings, keyed by identifiers assigned during bind()
@@ -283,6 +285,7 @@ struct usb_composite_driver {
         const char                              *name;
         const char                              *iProduct;
         const char                              *iManufacturer;
+        const char                              *iSerialNumber;
         const struct usb_device_descriptor      *dev;
         struct usb_gadget_strings               **strings;
         enum usb_device_speed                   max_speed;