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SubjectRe: [PATCH 2/3] mm: use vmalloc_array and vcalloc for array allocations
Hello,

On Tue, Mar 08, 2022 at 05:59:17AM -0500, Paolo Bonzini wrote:
> Instead of using array_size or just a multiply, use a function that
> takes care of both the multiplication and the overflow checks.
>
> Cc: linux-mm@kvack.org
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> mm/percpu-stats.c | 2 +-
> mm/swap_cgroup.c | 4 +---
> 2 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c
> index c6bd092ff7a3..e71651cda2de 100644
> --- a/mm/percpu-stats.c
> +++ b/mm/percpu-stats.c
> @@ -144,7 +144,7 @@ static int percpu_stats_show(struct seq_file *m, void *v)
> spin_unlock_irq(&pcpu_lock);
>
> /* there can be at most this many free and allocated fragments */
> - buffer = vmalloc(array_size(sizeof(int), (2 * max_nr_alloc + 1)));
> + buffer = vmalloc_array(2 * max_nr_alloc + 1, sizeof(int));
> if (!buffer)
> return -ENOMEM;
>
> diff --git a/mm/swap_cgroup.c b/mm/swap_cgroup.c
> index 7f34343c075a..5a9442979a18 100644
> --- a/mm/swap_cgroup.c
> +++ b/mm/swap_cgroup.c
> @@ -167,14 +167,12 @@ unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
> int swap_cgroup_swapon(int type, unsigned long max_pages)
> {
> void *array;
> - unsigned long array_size;
> unsigned long length;
> struct swap_cgroup_ctrl *ctrl;
>
> length = DIV_ROUND_UP(max_pages, SC_PER_PAGE);
> - array_size = length * sizeof(void *);
>
> - array = vzalloc(array_size);
> + array = vcalloc(length, sizeof(void *));
> if (!array)
> goto nomem;
>
> --
> 2.31.1
>

Acked-by: Dennis Zhou <dennis@kernel.org>

Thanks,
Dennis

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