memset arg64 to zero in the passthrough ioctls to avoid leaking contents
of kernel stack memory to userland via uninitialized padding fields
inserted by the compiler for alignment reasons.
Signed-off-by: NStephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>