Commit f01204ec authored Aug 17, 2020 by Maxim Mikityanskiy Committed by David S. Miller Aug 18, 2020

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: Maxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David 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);

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