Currently, we do memset() before reserving the area.  This may not cause
any problem, but it is somewhat weird.  So change execution order.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Jiang Liu <liuj97@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>