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/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 8588c09..426bfc7 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -26,6 +26,7 @@
 #include <linux/uaccess.h>
 #include <linux/kref.h>
 #include <linux/mutex.h>
+#include <linux/smp_lock.h>
 #include <linux/usb.h>
 #include <linux/usb/tmc.h>
 
@@ -113,6 +114,7 @@
 	struct usbtmc_device_data *data;
 	int retval = 0;
 
+	lock_kernel();
 	intf = usb_find_interface(&usbtmc_driver, iminor(inode));
 	if (!intf) {
 		printk(KERN_ERR KBUILD_MODNAME
@@ -128,6 +130,7 @@
 	filp->private_data = data;
 
 exit:
+	unlock_kernel();
 	return retval;
 }