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SubjectRe: [PATCH] md-linear: use struct_size() in kzalloc()
On Mon, Jan 7, 2019 at 10:35 AM Gustavo A. R. Silva
<gustavo@embeddedor.com> wrote:
>
> One of the more common cases of allocation size calculations is finding the
> size of a structure that has a zero-sized array at the end, along with memory
> for some number of elements for that array. For example:
>
> struct foo {
> int stuff;
> void *entry[];
> };
>
> instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
>
> Instead of leaving these open-coded and prone to type mistakes, we can now
> use the new struct_size() helper:
>
> instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Acked-by: Song Liu <songliubraving@fb.com>

> ---
> drivers/md/md-linear.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c
> index d45c697c0ebe..5998d78aa189 100644
> --- a/drivers/md/md-linear.c
> +++ b/drivers/md/md-linear.c
> @@ -96,8 +96,7 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
> int i, cnt;
> bool discard_supported = false;
>
> - conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(struct dev_info),
> - GFP_KERNEL);
> + conf = kzalloc(struct_size(conf, disks, raid_disks), GFP_KERNEL);
> if (!conf)
> return NULL;
>
> --
> 2.20.1
>

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