Make sure the mmap callback is set to NULL in the deferred io
cleanup function. This way we can enable and disable deferred
io on the fly.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>