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Date: Thu, 23 Oct 2025 06:55:17 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Paolo Abeni <pabeni@redhat.com>
Cc: Hangbin Liu <liuhangbin@gmail.com>, netdev@vger.kernel.org, "David S.
 Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Simon
 Horman <horms@kernel.org>, Stanislav Fomichev <sdf@fomichev.me>, "Dr. David
 Alan Gilbert" <linux@treblig.org>, Dong Chenchen
 <dongchenchen2@huawei.com>, Oscar Maes <oscmaes92@gmail.com>
Subject: Re: [PATCH net] net: vlan: sync VLAN features with lower device
Message-ID: <20251023065517.2d3dfca0@kernel.org>
In-Reply-To: <38605efc-32f5-4c78-a628-11f8f07668f0@redhat.com>
References: <20251021095658.86478-1-liuhangbin@gmail.com>
	<38605efc-32f5-4c78-a628-11f8f07668f0@redhat.com>
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On Thu, 23 Oct 2025 15:39:07 +0200 Paolo Abeni wrote:
> > @@ -193,6 +193,8 @@ int register_vlan_dev(struct net_device *dev, struct netlink_ext_ack *extack)
> >  	vlan_group_set_device(grp, vlan->vlan_proto, vlan_id, dev);
> >  	grp->nr_vlan_devs++;
> >  
> > +	netdev_change_features(dev);  
> 
> Is this just for NETIF_F_LRO? it feels a bit overkill for single flag.
> Also, why netdev_change_features() (vs netdev_update_features())?

Another thought -- isn't this a problem for more uppers?
Isn't this what all callers of netdev_upper_dev_link() effectively
need, and therefore perhaps we should stick it somewhere in the core
(netdev_upper_dev_link() itself or when device is registered) ?