Re: [PATCH v8 net-next 06/12] net: fec: convert to ndo_hwtstamp_get() and ndo_hwtstamp_set()

[Vladimir Oltean]

On Tue, Jul 18, 2023 at 03:20:13PM +0100, Russell King (Oracle) wrote:
> > +static int fec_hwtstamp_get(struct net_device *ndev,
> > +			    struct kernel_hwtstamp_config *config)
> > +{
> > +	struct fec_enet_private *fep = netdev_priv(ndev);
> > +	struct phy_device *phydev = ndev->phydev;
> > +
> > +	if (phy_has_hwtstamp(phydev))
> > +		return phy_mii_ioctl(phydev, config->ifr, SIOCGHWTSTAMP);
> > +
> > +	if (!fep->bufdesc_ex)
> > +		return -EOPNOTSUPP;
> 
> If the interface hasn't been brought up at least once, then phydev
> here will be NULL, and we'll drop through to this test. If the FEC
> doesn't support extended buffer descriptors, userspace will see
> -EOPNOTSUPP rather than -EINVAL. This could be misleading to userspace.
> 
> Does this need something like:
> 
> 	if (!netif_running(ndev))
> 		return -EINVAL;
> 
> before, or maybe just after phy_has_hwtstamp() to give equivalent
> behaviour?
> 
> > +static int fec_hwtstamp_set(struct net_device *ndev,
> > +			    struct kernel_hwtstamp_config *config,
> > +			    struct netlink_ext_ack *extack)
> > +{
> > +	struct fec_enet_private *fep = netdev_priv(ndev);
> > +	struct phy_device *phydev = ndev->phydev;
> > +
> > +	if (phy_has_hwtstamp(phydev)) {
> > +		fec_ptp_disable_hwts(ndev);
> > +
> > +		return phy_mii_ioctl(phydev, config->ifr, SIOCSHWTSTAMP);
> > +	}
> > +
> > +	if (!fep->bufdesc_ex)
> > +		return -EOPNOTSUPP;
> 
> Same comment here.

I will add back the netif_running() check to continue to not permit the
operation to go through, as before.