Re: [PATCH v2] staging: vt6655: use memset to make code clearer

From: Greg KH
Date: Fri Sep 09 2022 - 06:23:24 EST


On Fri, Sep 09, 2022 at 11:08:57AM +0200, Nam Cao wrote:
> A line of code sets the entire struct vnt_rdes0 to zero by treating it as
> unsigned int. This works because sizeof(unsigned int) is equal to
> sizeof(struct vnt_rdes0) (4 bytes). However it is not obvious what this
> code is doing. Re-write this using memset to make the code clearer.
>
> Signed-off-by: Nam Cao <namcaov@xxxxxxxxx>
> ---
> v2: re-write commit message because previous message describes a
> non-existent problem.
>
> drivers/staging/vt6655/device_main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
> index 8e2a976aaaad..a38657769c20 100644
> --- a/drivers/staging/vt6655/device_main.c
> +++ b/drivers/staging/vt6655/device_main.c
> @@ -867,7 +867,7 @@ static bool device_alloc_rx_buf(struct vnt_private *priv,
> return false;
> }
>
> - *((unsigned int *)&rd->rd0) = 0; /* FIX cast */
> + memset((void *)&rd->rd0, 0, sizeof(rd->rd0));

Why do you have to cast this to (void *)? That should almost never be
needed.

thanks,

greg k-h