On Mon, Aug 17, 2020 at 04:34:06PM +0300, Maxim Mikityanskiy wrote:
> ethtool-netlink ignores dev->hw_features and may confuse the drivers by
> asking them to enable features not in the hw_features bitmask. For
> example:
> 
> 1. ethtool -k eth0
>    tls-hw-tx-offload: off [fixed]
> 2. ethtool -K eth0 tls-hw-tx-offload on
>    tls-hw-tx-offload: on
> 3. ethtool -k eth0
>    tls-hw-tx-offload: on [fixed]
> 
> Fitler out dev->hw_features from req_wanted to fix it and to resemble
> the legacy ethtool behavior.
> 
> Fixes: 0980bfcd6954 ("ethtool: set netdev features with FEATURES_SET request")
> Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>

Reviewed-by: Michal Kubecek <mkubecek@suse.cz>

> ---
>  net/ethtool/features.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/ethtool/features.c b/net/ethtool/features.c
> index ec196f0fddc9..6b288bfd7678 100644
> --- a/net/ethtool/features.c
> +++ b/net/ethtool/features.c
> @@ -273,7 +273,8 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info)
>  		goto out_rtnl;
>  	}
>  
> -	dev->wanted_features = ethnl_bitmap_to_features(req_wanted);
> +	dev->wanted_features &= ~dev->hw_features;
> +	dev->wanted_features |= ethnl_bitmap_to_features(req_wanted) & dev->hw_features;
>  	__netdev_update_features(dev);
>  	ethnl_features_to_bitmap(new_active, dev->features);
>  	mod = !bitmap_equal(old_active, new_active, NETDEV_FEATURE_COUNT);
> -- 
> 2.25.1
>