Re: [PATCH 1/2][next] mm: memcontrol: Use flex_array_size() helper in memcpy()
From: Michal Hocko <mhocko@suse.com>
Date: 2020-08-04 13:25:38
Also in:
linux-mm, lkml
On Fri 31-07-20 12:12:53, Gustavo A. R. Silva wrote:
Make use of the flex_array_size() helper to calculate the size of a flexible array member within an enclosing structure. This helper offers defense-in-depth against potential integer overflows, while at the same time makes it explicitly clear that we are dealing with a flexible array member. Also, remove unnecessary braces.
I was not aware of this helper. The code looks slightly better.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
quoted hunk ↗ jump to hunk
--- mm/memcontrol.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e84c2b5596f2..bd7f972ceea4 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c@@ -4246,10 +4246,9 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg, new->size = size; /* Copy thresholds (if any) to new array */ - if (thresholds->primary) { - memcpy(new->entries, thresholds->primary->entries, (size - 1) * - sizeof(struct mem_cgroup_threshold)); - } + if (thresholds->primary) + memcpy(new->entries, thresholds->primary->entries, + flex_array_size(new, entries, size - 1)); /* Add new threshold */ new->entries[size - 1].eventfd = eventfd;-- 2.27.0
-- Michal Hocko SUSE Labs