kfifo: move out spinlock

Move the pointer to the spinlock out of struct kfifo.  Most users in
tree do not actually use a spinlock, so the few exceptions now have to
call kfifo_{get,put}_locked, which takes an extra argument to a
spinlock.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index bbe005c..61eef18 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -285,7 +285,7 @@
 		return 0;
 
 	data = port->write_urb->transfer_buffer;
-	count = kfifo_get(port->write_fifo, data, port->bulk_out_size);
+	count = kfifo_get_locked(port->write_fifo, data, port->bulk_out_size, &port->lock);
 	usb_serial_debug_data(debug, &port->dev, __func__, count, data);
 
 	/* set up our urb */
@@ -345,7 +345,7 @@
 		return usb_serial_multi_urb_write(tty, port,
 						  buf, count);
 
-	count = kfifo_put(port->write_fifo, buf, count);
+	count = kfifo_put_locked(port->write_fifo, buf, count, &port->lock);
 	result = usb_serial_generic_write_start(port);
 
 	if (result >= 0)