Commit f01204ec authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by David S. Miller
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ethtool: Don't omit the netlink reply if no features were changed 



The legacy ethtool userspace tool shows an error when no features could
be changed. It's useful to have a netlink reply to be able to show this
error when __netdev_update_features wasn't called, for example:

1. ethtool -k eth0
   large-receive-offload: off
2. ethtool -K eth0 rx-fcs on
3. ethtool -K eth0 lro on
   Could not change any device features
   rx-lro: off [requested on]
4. ethtool -K eth0 lro on
   # The output should be the same, but without this patch the kernel
   # doesn't send the reply, and ethtool is unable to detect the error.

This commit makes ethtool-netlink always return a reply when requested,
and it still avoids unnecessary calls to __netdev_update_features if the
wanted features haven't changed.

Fixes: 0980bfcd ("ethtool: set netdev features with FEATURES_SET request")
Signed-off-by: default avatarMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: default avatarMichal Kubecek <mkubecek@suse.cz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2847bfed

net/ethtool/features.c

+4 −7
Original line number Diff line number Diff line
@@ -268,14 +268,11 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info) 
	bitmap_and(req_wanted, req_wanted, req_mask, NETDEV_FEATURE_COUNT);

	bitmap_andnot(new_wanted, old_wanted, req_mask, NETDEV_FEATURE_COUNT);

	bitmap_or(req_wanted, new_wanted, req_wanted, NETDEV_FEATURE_COUNT);

	if (bitmap_equal(req_wanted, old_wanted, NETDEV_FEATURE_COUNT)) {

		ret = 0;

		goto out_rtnl;

	}



	if (!bitmap_equal(req_wanted, old_wanted, NETDEV_FEATURE_COUNT)) {

		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);