Provide a new command line knob dm.deferred_device_removal which will enable deferred device deactivation if driver and library support it. This patch also checks for library support and driver version. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Upstream-commit: 15c158b20725fd62e2ee0a72ffaf1617852cd0d9 Component: engine