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

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

[Alexander Lobakin]

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()).

Fixes: 0980bfcd6954 ("ethtool: set netdev features with FEATURES_SET request")
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
 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 8ee4cdbd6b82..38f526f2125d 100644
--- a/net/ethtool/features.c
+++ b/net/ethtool/features.c
@@ -279,8 +279,9 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info)
 					  wanted_diff_mask, new_active,
 					  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

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

[Jakub Kicinski]

On Thu, 05 Nov 2020 16:26:58 +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()).
> 
> Fixes: 0980bfcd6954 ("ethtool: set netdev features with FEATURES_SET request")
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>

LGTM, one nit below

> diff --git a/net/ethtool/features.c b/net/ethtool/features.c
> index 8ee4cdbd6b82..38f526f2125d 100644
> --- a/net/ethtool/features.c
> +++ b/net/ethtool/features.c
> @@ -279,8 +279,9 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info)
>  					  wanted_diff_mask, new_active,
>  					  active_diff_mask, compact);
>  	}
> +

I think the reply and notification are purposefully grouped, please
drop this extra new line.

>  	if (mod)
> -		ethtool_notify(dev, ETHTOOL_MSG_FEATURES_NTF, NULL);
> +		netdev_features_change(dev);
>  
>  out_rtnl:
>  	rtnl_unlock();