1 files changed, 64 insertions, 32 deletions

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index eaa9a599df63..717de39627c7 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -24,6 +24,7 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/device.h>
+#include <linux/utsname.h>
 
 #include <linux/usb/composite.h>
 
@@ -69,6 +70,8 @@ static char *iSerialNumber;
 module_param(iSerialNumber, charp, 0);
 MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");
 
+static char composite_manufacturer[50];
+
 /*-------------------------------------------------------------------------*/
 
 /**
@@ -599,6 +602,7 @@ static int get_string(struct usb_composite_dev *cdev,
         struct usb_configuration        *c;
         struct usb_function             *f;
         int                             len;
+        const char                      *str;
 
         /* Yes, not only is USB's I18N support probably more than most
          * folk will ever care about ... also, it's all supported here.
@@ -638,9 +642,29 @@ static int get_string(struct usb_composite_dev *cdev,
                 return s->bLength;
         }
 
-        /* Otherwise, look up and return a specified string.  String IDs
-         * are device-scoped, so we look up each string table we're told
-         * about.  These lookups are infrequent; simpler-is-better here.
+        /* Otherwise, look up and return a specified string.  First
+         * check if the string has not been overridden.
+         */
+        if (cdev->manufacturer_override == id)
+                str = iManufacturer ?: composite->iManufacturer ?:
+                        composite_manufacturer;
+        else if (cdev->product_override == id)
+                str = iProduct ?: composite->iProduct;
+        else if (cdev->serial_override == id)
+                str = iSerialNumber;
+        else
+                str = NULL;
+        if (str) {
+                struct usb_gadget_strings strings = {
+                        .language = language,
+                        .strings  = &(struct usb_string) { 0xff, str }
+                };
+                return usb_gadget_get_string(&strings, 0xff, buf);
+        }
+
+        /* String IDs are device-scoped, so we look up each string
+         * table we're told about.  These lookups are infrequent;
+         * simpler-is-better here.
          */
         if (composite->strings) {
                 len = lookup_string(composite->strings, buf, language, id);
@@ -1025,26 +1049,17 @@ composite_unbind(struct usb_gadget *gadget)
         composite = NULL;
 }
 
-static void
-string_override_one(struct usb_gadget_strings *tab, u8 id, const char *s)
+static u8 override_id(struct usb_composite_dev *cdev, u8 *desc)
 {
-        struct usb_string               *str = tab->strings;
-
-        for (str = tab->strings; str->s; str++) {
-                if (str->id == id) {
-                        str->s = s;
-                        return;
-                }
+        if (!*desc) {
+                int ret = usb_string_id(cdev);
+                if (unlikely(ret < 0))
+                        WARNING(cdev, "failed to override string ID\n");
+                else
+                        *desc = ret;
         }
-}
 
-static void
-string_override(struct usb_gadget_strings **tab, u8 id, const char *s)
-{
-        while (*tab) {
-                string_override_one(*tab, id, s);
-                tab++;
-        }
+        return *desc;
 }
 
 static int composite_bind(struct usb_gadget *gadget)
@@ -1107,19 +1122,34 @@ static int composite_bind(struct usb_gadget *gadget)
         cdev->desc = *composite->dev;
         cdev->desc.bMaxPacketSize0 = gadget->ep0->maxpacket;
 
-        /* strings can't be assigned before bind() allocates the
-         * releavnt identifiers
-         */
-        if (cdev->desc.iManufacturer && iManufacturer)
-                string_override(composite->strings,
-                        cdev->desc.iManufacturer, iManufacturer);
-        if (cdev->desc.iProduct && iProduct)
-                string_override(composite->strings,
-                        cdev->desc.iProduct, iProduct);
-        if (cdev->desc.iSerialNumber && iSerialNumber)
-                string_override(composite->strings,
-                        cdev->desc.iSerialNumber, iSerialNumber);
+        /* stirng overrides */
+        if (iManufacturer || !cdev->desc.iManufacturer) {
+                if (!iManufacturer && !composite->iManufacturer &&
+                    !*composite_manufacturer)
+                        snprintf(composite_manufacturer,
+                                 sizeof composite_manufacturer,
+                                 "%s %s with %s",
+                                 init_utsname()->sysname,
+                                 init_utsname()->release,
+                                 gadget->name);
+
+                cdev->manufacturer_override =
+                        override_id(cdev, &cdev->desc.iManufacturer);
+        }
+
+        if (iProduct || (!cdev->desc.iProduct && composite->iProduct))
+                cdev->product_override =
+                        override_id(cdev, &cdev->desc.iProduct);
+
+        if (iSerialNumber)
+                cdev->serial_override =
+                        override_id(cdev, &cdev->desc.iSerialNumber);
+
+        /* has userspace failed to provide a serial number? */
+        if (composite->needs_serial && !cdev->desc.iSerialNumber)
+                WARNING(cdev, "userspace failed to provide iSerialNumber\n");
 
+        /* finish up */
         status = device_create_file(&gadget->dev, &dev_attr_suspended);
         if (status)
                 goto fail;
@@ -1217,6 +1247,8 @@ int usb_composite_register(struct usb_composite_driver *driver)
         if (!driver || !driver->dev || !driver->bind || composite)
                 return -EINVAL;
 
+        if (!driver->iProduct)
+                driver->iProduct = driver->name;
         if (!driver->name)
                 driver->name = "composite";
         composite_driver.function =  (char *) driver->name;