Re: [PATCH v2 net] ethtool: netlink: add missing netdev_features_change() call

[Michal Kubecek]

On Sun, Nov 08, 2020 at 12:46:15AM +0000, Alexander Lobakin wrote:
> After updating userspace Ethtool from 5.7 to 5.9, I noticed that
> NETDEV_FEAT_CHANGE is no more raised when changing netdev features
> through Ethtool.
> That's because the old Ethtool ioctl interface always calls
> netdev_features_change() at the end of user request processing to
> inform the kernel that our netdevice has some features changed, but
> the new Netlink interface does not. Instead, it just notifies itself
> with ETHTOOL_MSG_FEATURES_NTF.
> Replace this ethtool_notify() call with netdev_features_change(), so
> the kernel will be aware of any features changes, just like in case
> with the ioctl interface. This does not omit Ethtool notifications,
> as Ethtool itself listens to NETDEV_FEAT_CHANGE and drops
> ETHTOOL_MSG_FEATURES_NTF on it
> (net/ethtool/netlink.c:ethnl_netdev_event()).
> 
> From v1 [1]:
> - dropped extra new line as advised by Jakub;
> - no functional changes.
> 
> [1] https://lore.kernel.org/netdev/AlZXQ2o5uuTVHCfNGOiGgJ8vJ3KgO5YIWAnQjH0cDE@xxxxxxxxxxxxxxxxxxxx
> 
> Fixes: 0980bfcd6954 ("ethtool: set netdev features with FEATURES_SET request")
> Signed-off-by: Alexander Lobakin <alobakin@xxxxx>

Reviewed-by: Michal Kubecek <mkubecek@xxxxxxx>

> ---
>  net/ethtool/features.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/ethtool/features.c b/net/ethtool/features.c
> index 8ee4cdbd6b82..1c9f4df273bd 100644
> --- a/net/ethtool/features.c
> +++ b/net/ethtool/features.c
> @@ -280,7 +280,7 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info)
>  					  active_diff_mask, compact);
>  	}
>  	if (mod)
> -		ethtool_notify(dev, ETHTOOL_MSG_FEATURES_NTF, NULL);
> +		netdev_features_change(dev);
>  
>  out_rtnl:
>  	rtnl_unlock();
> -- 
> 2.29.2
> 
>

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