Subject: Re: [RFC PATCH v3 3/5] Add ndo_hwtstamp_get/set support to vlan code path

From: Jakub Kicinski <[email-masked]>
Date: Wed, 5 Apr 2023 09:42:10 -0700

On Wed,  5 Apr 2023 00:33:23 -0600 Maxim Georgiev wrote:
> +static int vlan_dev_hwtstamp(struct net_device *dev, struct ifreq *ifr, int cmd)
> +{
> +	const struct net_device_ops *ops = dev->netdev_ops;
> +	struct kernel_hwtstamp_config kernel_config = {};
> +	struct hwtstamp_config config;
> +	int err;
> +
> +	if (!netif_device_present(dev))
> +		return -ENODEV;
> +
> +	if ((cmd == SIOCSHWTSTAMP && !ops->ndo_hwtstamp_set) ||
> +	    (cmd == SIOCGHWTSTAMP && !ops->ndo_hwtstamp_get)) {
> +		if (ops->ndo_eth_ioctl) {
> +			return ops->ndo_eth_ioctl(real_dev, &ifr, cmd);
> +		else
> +			return -EOPNOTSUPP;
> +	}
> +
> +	kernel_config.ifr = ifr;
> +	if (cmd == SIOCSHWTSTAMP) {
> +		if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
> +			return -EFAULT;
> +
> +		hwtstamp_config_to_kernel(&kernel_config, &config);
> +		err = ops->ndo_hwtstamp_set(dev, &kernel_config, NULL);
> +	} else if (cmd == SIOCGHWTSTAMP) {
> +		err = ops->ndo_hwtstamp_get(dev, &kernel_config, NULL);
> +	}
> +
> +	if (err)
> +		return err;
> +
> +	hwtstamp_kernel_to_config(&config, &kernel_config);
> +	if (copy_to_user(ifr->ifr_data, &config, sizeof(config)))
> +		return -EFAULT;
> +	return 0;
> +}

This needs to live in the core. I think the real_dev is a lower of the
vlan device? All the vlan driver should do is attach the generic helper:

	.ndo_hwtstamp_get = generic_hwtstamp_get_lower,

and the same for set. No?