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Date:   Tue, 8 Dec 2020 11:27:30 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     Jarod Wilson <jarod@redhat.com>
Cc:     linux-kernel@vger.kernel.org, Ivan Vecera <ivecera@redhat.com>,
        Jay Vosburgh <j.vosburgh@gmail.com>,
        Veaceslav Falico <vfalico@gmail.com>,
        Andy Gospodarek <andy@greyhouse.net>,
        "David S. Miller" <davem@davemloft.net>,
        Thomas Davis <tadavis@lbl.gov>, netdev@vger.kernel.org
Subject: Re: [PATCH net v4] bonding: fix feature flag setting at init time
Message-ID: <20201208112730.05d13f3d@kicinski-fedora-pc1c0hjn.DHCP.thefacebook.com>
In-Reply-To: <20201205172229.576587-1-jarod@redhat.com>
References: <20201203004357.3125-1-jarod@redhat.com>
        <20201205172229.576587-1-jarod@redhat.com>
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On Sat,  5 Dec 2020 12:22:29 -0500 Jarod Wilson wrote:
> Don't try to adjust XFRM support flags if the bond device isn't yet
> registered. Bad things can currently happen when netdev_change_features()
> is called without having wanted_features fully filled in yet. This code
> runs both on post-module-load mode changes, as well as at module init
> time, and when run at module init time, it is before register_netdevice()
> has been called and filled in wanted_features. The empty wanted_features
> led to features also getting emptied out, which was definitely not the
> intended behavior, so prevent that from happening.
> 
> Originally, I'd hoped to stop adjusting wanted_features at all in the
> bonding driver, as it's documented as being something only the network
> core should touch, but we actually do need to do this to properly update
> both the features and wanted_features fields when changing the bond type,
> or we get to a situation where ethtool sees:
> 
>     esp-hw-offload: off [requested on]
> 
> I do think we should be using netdev_update_features instead of
> netdev_change_features here though, so we only send notifiers when the
> features actually changed.
> 
> Fixes: a3b658cfb664 ("bonding: allow xfrm offload setup post-module-load")
> Reported-by: Ivan Vecera <ivecera@redhat.com>
> Suggested-by: Ivan Vecera <ivecera@redhat.com>

Applied, thanks!