[PATCH 5.7 13/15] ethtool: Dont omit the netlink reply if no features were changed

Greg Kroah-Hartman
2020-08-26T12:04:19Z

From: Maxim Mikityanskiy <maximmi@mellanox.com>

[ Upstream commit f01204ec8be7ea5e8f0230a7d4200e338d563bde ]

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: 0980bfcd6954 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ethtool/features.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

--- a/net/ethtool/features.c
+++ b/net/ethtool/features.c
@@ -268,14 +268,11 @@ int ethnl_set_features(struct sk_buff *s
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);
}
-
- 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);