linux-kernel - Re: [PATCH] PM: hibernate: Use vmalloc_array() and vcalloc() to improve code

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Message-ID: <CAJZ5v0iEk2MeXLabuafZdQ3iWaVeB2srrXgZ35=qacOyOknWQQ@mail.gmail.com>
Date: Mon, 25 Aug 2025 20:47:55 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Qianfeng Rong <rongqianfeng@...o.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>, Pavel Machek <pavel@...nel.org>, 
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PM: hibernate: Use vmalloc_array() and vcalloc() to
 improve code

On Sun, Aug 17, 2025 at 10:36 AM Qianfeng Rong <rongqianfeng@...o.com> wrote:
>
> Remove array_size() calls and replace vmalloc() and vzalloc() with
> vmalloc_array() and vcalloc() respectively to simplify the code in
> save_compressed_image() and load_compressed_image().  vmalloc_array()
> is also optimized better, resulting in less instructions being used,
> and vmalloc_array() handling overflow is more concise [1].
>
> [1]: https://lore.kernel.org/lkml/abc66ec5-85a4-47e1-9759-2f60ab111971@vivo.com/
>
> Signed-off-by: Qianfeng Rong <rongqianfeng@...o.com>
> ---
>  kernel/power/swap.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/power/swap.c b/kernel/power/swap.c
> index ad13c461b657..0beff7eeaaba 100644
> --- a/kernel/power/swap.c
> +++ b/kernel/power/swap.c
> @@ -712,7 +712,7 @@ static int save_compressed_image(struct swap_map_handle *handle,
>                 goto out_clean;
>         }
>
> -       data = vzalloc(array_size(nr_threads, sizeof(*data)));
> +       data = vcalloc(nr_threads, sizeof(*data));
>         if (!data) {
>                 pr_err("Failed to allocate %s data\n", hib_comp_algo);
>                 ret = -ENOMEM;
> @@ -1225,14 +1225,14 @@ static int load_compressed_image(struct swap_map_handle *handle,
>         nr_threads = num_online_cpus() - 1;
>         nr_threads = clamp_val(nr_threads, 1, CMP_THREADS);
>
> -       page = vmalloc(array_size(CMP_MAX_RD_PAGES, sizeof(*page)));
> +       page = vmalloc_array(CMP_MAX_RD_PAGES, sizeof(*page));
>         if (!page) {
>                 pr_err("Failed to allocate %s page\n", hib_comp_algo);
>                 ret = -ENOMEM;
>                 goto out_clean;
>         }
>
> -       data = vzalloc(array_size(nr_threads, sizeof(*data)));
> +       data = vcalloc(nr_threads, sizeof(*data));
>         if (!data) {
>                 pr_err("Failed to allocate %s data\n", hib_comp_algo);
>                 ret = -ENOMEM;
> --

Applied as 6.18 material with some edits in the changelog, thanks!