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Subject[PATCH 1/2][next] mm: memcontrol: Use flex_array_size() helper in memcpy()
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.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
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
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