Avoid crashing if the private_data pointer happens to be NULL. This has
been seen sometimes when a host reset happens, notably when there are
many LUNs:
Signed-off-by: Mark Rustad <mark.d.rustad@intel.com> Tested-by: Marcus Dennis <marcusx.e.dennis@intel.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>