Re: [PATCH net-next] ethtool: ioctl: improve error checking for set_wol

[Simon Horman]

+ Daniil Tatianin <d-tatianin@xxxxxxxxxxxxxx>, Andrew Lunn <andrew@xxxxxxx>
  as per ./scripts/get_maintainer.pl --git-min-percent 25 net/ethtool/ioctl.c

On Wed, May 31, 2023 at 01:53:49PM -0700, Justin Chen wrote:
> The netlink version of set_wol checks for not supported wolopts and avoids
> setting wol when the correct wolopt is already set. If we do the same with
> the ioctl version then we can remove these checks from the driver layer.

Hi Justin,

Are you planning follow-up patches for the driver layer?

> Signed-off-by: Justin Chen <justin.chen@xxxxxxxxxxxx>
> ---
>  net/ethtool/ioctl.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
> index 6bb778e10461..80f456f83db0 100644
> --- a/net/ethtool/ioctl.c
> +++ b/net/ethtool/ioctl.c
> @@ -1436,15 +1436,25 @@ static int ethtool_get_wol(struct net_device *dev, char __user *useraddr)
>  
>  static int ethtool_set_wol(struct net_device *dev, char __user *useraddr)
>  {
> -	struct ethtool_wolinfo wol;
> +	struct ethtool_wolinfo wol, cur_wol;
>  	int ret;
>  
> -	if (!dev->ethtool_ops->set_wol)
> +	if (!dev->ethtool_ops->get_wol || !dev->ethtool_ops->set_wol)
>  		return -EOPNOTSUPP;

Are there cases where (in-tree) drivers provide set_wol byt not get_wol?
If so, does this break their set_wol support?

>  
> +	memset(&cur_wol, 0, sizeof(struct ethtool_wolinfo));
> +	cur_wol.cmd = ETHTOOL_GWOL;
> +	dev->ethtool_ops->get_wol(dev, &cur_wol);
> +
>  	if (copy_from_user(&wol, useraddr, sizeof(wol)))
>  		return -EFAULT;
>  
> +	if (wol.wolopts & ~cur_wol.supported)
> +		return -EOPNOTSUPP;
> +
> +	if (wol.wolopts == cur_wol.wolopts)
> +		return 0;
> +
>  	ret = dev->ethtool_ops->set_wol(dev, &wol);
>  	if (ret)
>  		return ret;