Re: [PATCH -next] ethernet: renesas: Use div64_ul instead of do_div

[Sergey Shtylyov]

Hello!

   Why you didn't Cc me (as a reviewer)?

On 18.11.2021 5:50, Yang Li wrote:

> do_div() does a 64-by-32 division. Here the divisor is an
> unsigned long which on some platforms is 64 bit wide. So use
> div64_ul instead of do_div to avoid a possible truncation.
>
> Eliminate the following coccicheck warning:
> ./drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:2742:1-7: WARNING:
> do_div() does a 64-by-32 division, please consider using div64_ul
> instead.
>
> Reported-by: Abaci Robot <abaci@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Yang Li <yang.lee@xxxxxxxxxxxxxxxxx>
> ---
>   drivers/net/ethernet/renesas/ravb_main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index b4c597f..2b89710 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2489,7 +2489,7 @@ static int ravb_set_gti(struct net_device *ndev)
>   		return -EINVAL;
>   
>   	inc = 1000000000ULL << 20;
> -	do_div(inc, rate);
> +	inc = div64_ul(inc, rate);

   Why not just:

	inc = div64_ul(1000000000ULL << 20, rate);

>   	if (inc < GTI_TIV_MIN || inc > GTI_TIV_MAX) {
>   		dev_err(dev, "gti.tiv increment 0x%llx is outside the range 0x%x - 0x%x\n",

MBR, Sergey