BugLink: http://bugs.launchpad.net/bugs/1646204

Userspace should be implementing VPD B0 (Block Limits) to inform the
initiator of max data size, but just in case we do get a too-large request,
do what the spec says and return INVALID_CDB_FIELD.

Make sure to unlock udev->cmdr_lock before returning.
Signed-off-by: Andy Grover <agrover@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
(back ported from linux-next commit 554617b2)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

Conflicts:
	drivers/target/target_core_user.c
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>