The size of struct rcu_head may be changed. When it becomes larger,
it may pollute the data after struct slab.
Acked-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NPekka Enberg <penberg@kernel.org>