1 files changed, 48 insertions, 19 deletions

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index b1b85abb9a2d..4e2c6df8d3cc 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -64,6 +64,43 @@ MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
 
 
 /**
+ * usb_find_alt_setting() - Given a configuration, find the alternate setting
+ * for the given interface.
+ * @config - the configuration to search (not necessarily the current config).
+ * @iface_num - interface number to search in
+ * @alt_num - alternate interface setting number to search for.
+ *
+ * Search the configuration's interface cache for the given alt setting.
+ */
+struct usb_host_interface *usb_find_alt_setting(
+		struct usb_host_config *config,
+		unsigned int iface_num,
+		unsigned int alt_num)
+{
+	struct usb_interface_cache *intf_cache = NULL;
+	int i;
+
+	for (i = 0; i < config->desc.bNumInterfaces; i++) {
+		if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
+				== iface_num) {
+			intf_cache = config->intf_cache[i];
+			break;
+		}
+	}
+	if (!intf_cache)
+		return NULL;
+	for (i = 0; i < intf_cache->num_altsetting; i++)
+		if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
+			return &intf_cache->altsetting[i];
+
+	printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
+			"config %u\n", alt_num, iface_num,
+			config->desc.bConfigurationValue);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(usb_find_alt_setting);
+
+/**
  * usb_ifnum_to_if - get the interface object with a given interface number
  * @dev: the device whose current configuration is considered
  * @ifnum: the desired interface
@@ -130,24 +167,17 @@ struct usb_host_interface *usb_altnum_to_altsetting(
 }
 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
 
-struct find_interface_arg {
-	int minor;
-	struct usb_interface *interface;
-};
-
 static int __find_interface(struct device *dev, void *data)
 {
-	struct find_interface_arg *arg = data;
+	int *minor = data;
 	struct usb_interface *intf;
 
 	if (!is_usb_interface(dev))
 		return 0;
 
 	intf = to_usb_interface(dev);
-	if (intf->minor != -1 && intf->minor == arg->minor) {
-		arg->interface = intf;
+	if (intf->minor != -1 && intf->minor == *minor)
 		return 1;
-	}
 	return 0;
 }
 
@@ -156,21 +186,20 @@ static int __find_interface(struct device *dev, void *data)
  * @drv: the driver whose current configuration is considered
  * @minor: the minor number of the desired device
  *
- * This walks the driver device list and returns a pointer to the interface
+ * This walks the bus device list and returns a pointer to the interface
  * with the matching minor.  Note, this only works for devices that share the
  * USB major number.
  */
 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
 {
-	struct find_interface_arg argb;
-	int retval;
+	struct device *dev;
+
+	dev = bus_find_device(&usb_bus_type, NULL, &minor, __find_interface);
+
+	/* Drop reference count from bus_find_device */
+	put_device(dev);
 
-	argb.minor = minor;
-	argb.interface = NULL;
-	/* eat the error, it will be in argb.interface */
-	retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
-					__find_interface);
-	return argb.interface;
+	return dev ? to_usb_interface(dev) : NULL;
 }
 EXPORT_SYMBOL_GPL(usb_find_interface);
 
@@ -1038,7 +1067,7 @@ static struct notifier_block usb_bus_nb = {
 struct dentry *usb_debug_root;
 EXPORT_SYMBOL_GPL(usb_debug_root);
 
-struct dentry *usb_debug_devices;
+static struct dentry *usb_debug_devices;
 
 static int usb_debugfs_init(void)
 {