USB: Push BKL on open down into the drivers

Straightforward push into the drivers to allow
auditing individual drivers separately

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/misc/usblcd.c b/drivers/usb/misc/usblcd.c
index 499d750..90aede9 100644
--- a/drivers/usb/misc/usblcd.c
+++ b/drivers/usb/misc/usblcd.c
@@ -74,10 +74,12 @@
 	struct usb_interface *interface;
 	int subminor, r;
 
+	lock_kernel();
 	subminor = iminor(inode);
 
 	interface = usb_find_interface(&lcd_driver, subminor);
 	if (!interface) {
+		unlock_kernel();
 		err ("USBLCD: %s - error, can't find device for minor %d",
 		     __func__, subminor);
 		return -ENODEV;
@@ -87,6 +89,7 @@
 	dev = usb_get_intfdata(interface);
 	if (!dev) {
 		mutex_unlock(&open_disc_mutex);
+		unlock_kernel();
 		return -ENODEV;
 	}
 
@@ -98,11 +101,13 @@
 	r = usb_autopm_get_interface(interface);
 	if (r < 0) {
 		kref_put(&dev->kref, lcd_delete);
+		unlock_kernel();
 		return r;
 	}
 
 	/* save our object in the file's private structure */
 	file->private_data = dev;
+	unlock_kernel();
 
 	return 0;
 }