On Mon, Aug 05, 2019 at 07:06:38PM -0500, Gustavo A. R. Silva 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 touchpad_protocol {
> ...
> struct tp_finger fingers[0];
> };
>
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes.
>
> So, replace the following form:
>
> sizeof(*tp) + tp->number_of_fingers * sizeof(tp->fingers[0]);
>
> with:
>
> struct_size(tp, fingers, tp->number_of_fingers)
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Applied, thank you.
> ---
> drivers/input/keyboard/applespi.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/input/keyboard/applespi.c b/drivers/input/keyboard/applespi.c
> index acf34a5ff571..584289b67fb3 100644
> --- a/drivers/input/keyboard/applespi.c
> +++ b/drivers/input/keyboard/applespi.c
> @@ -1494,8 +1494,7 @@ static void applespi_got_data(struct applespi_data *applespi)
> size_t tp_len;
>
> tp = &message->touchpad;
> - tp_len = sizeof(*tp) +
> - tp->number_of_fingers * sizeof(tp->fingers[0]);
> + tp_len = struct_size(tp, fingers, tp->number_of_fingers);
>
> if (le16_to_cpu(message->length) + 2 != tp_len) {
> dev_warn_ratelimited(&applespi->spi->dev,
> --
> 2.22.0
>
--
Dmitry
