usb: gadget: composite: Fix corruption when changing configuration

Remove the config from the configs list before releasing the spinlock.
Otherwise the other cpu might be processing a SET_CONFIGURATION that
will switch to the configuration that is being released.

Change-Id: Id4da0d0e18ead63e20cb236cd1d3e8e6d116acce
Signed-off-by: Benoit Goby <benoit@android.com>
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 343d842..8f82fc0 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -775,7 +775,7 @@
 	return status;
 }
 
-static int remove_config(struct usb_composite_dev *cdev,
+static int unbind_config(struct usb_composite_dev *cdev,
 			      struct usb_configuration *config)
 {
 	while (!list_empty(&config->functions)) {
@@ -790,7 +790,6 @@
 			/* may free memory for "f" */
 		}
 	}
-	list_del(&config->list);
 	if (config->unbind) {
 		DBG(cdev, "unbind config '%s'/%p\n", config->label, config);
 		config->unbind(config);
@@ -818,9 +817,11 @@
 	if (cdev->config == config)
 		reset_config(cdev);
 
+	list_del(&config->list);
+
 	spin_unlock_irqrestore(&cdev->lock, flags);
 
-	return remove_config(cdev, config);
+	return unbind_config(cdev, config);
 }
 
 /*-------------------------------------------------------------------------*/
@@ -1379,7 +1380,8 @@
 		struct usb_configuration	*c;
 		c = list_first_entry(&cdev->configs,
 				struct usb_configuration, list);
-		remove_config(cdev, c);
+		list_del(&c->list);
+		unbind_config(cdev, c);
 	}
 	if (composite->unbind)
 		composite->unbind(cdev);