[PATCH] staging: greybus: power_supply: Use struct_size() helper

[Johan Hovold]

On Wed, Apr 03, 2019 at 03:58:01PM -0500, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes, in particular in the
> context in which this code is being used.
> 
> So, replace code of the following form:
> 
> sizeof(*resp) + props_count * sizeof(struct gb_power_supply_props_desc)
> 
> with:
> 
> struct_size(resp, props, props_count)
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo at embeddedor.com>
> ---
>  drivers/staging/greybus/power_supply.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/greybus/power_supply.c b/drivers/staging/greybus/power_supply.c
> index 0529e5628c24..40cc2d462ba0 100644
> --- a/drivers/staging/greybus/power_supply.c
> +++ b/drivers/staging/greybus/power_supply.c
> @@ -520,8 +520,8 @@ static int gb_power_supply_prop_descriptors_get(struct gb_power_supply *gbpsy)
>  
>  	op = gb_operation_create(connection,
>  				 GB_POWER_SUPPLY_TYPE_GET_PROP_DESCRIPTORS,
> -				 sizeof(req), sizeof(*resp) + props_count *

This patch looks good, but I noticed a bug here in the current code,
which should be fixed before applying this clean up.

sizeof(req) should have been sizeof(*req) above.

> -				 sizeof(struct gb_power_supply_props_desc),
> +				 sizeof(req),
> +				 struct_size(resp, props, props_count),
>  				 GFP_KERNEL);
>  	if (!op)
>  		return -ENOMEM;

I've just submitted a fix (and CCed you as well). 

Would you mind respinning on top of that one?

Thanks,
Johan