| Message ID | ddd60dae2d9aea1ccdd2be66634815c93696125e.1596214831.git.gustavoars@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Use flexible_array_size() helper in memcpy() | expand |
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> > --- > 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
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;
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(-)