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From: Ziwei Xiao <ziweixiao@google.com>
Date: Thu, 9 May 2024 17:19:00 -0700
Message-ID: <CAG-FcCNGsP3FnB6HzrcQxX4kKEHzimYaQnFcBK63z_kFTEQKgw@mail.gmail.com>
Subject: Re: [PATCH net-next 5/5] gve: Add flow steering ethtool support
To: Markus Elfring <Markus.Elfring@web.de>
Cc: Jeroen de Borst <jeroendb@google.com>, netdev@vger.kernel.org, 
	kernel-janitors@vger.kernel.org, 
	Harshitha Ramamurthy <hramamurthy@google.com>, Praveen Kaligineedi <pkaligineedi@google.com>, 
	Willem de Bruijn <willemb@google.com>, LKML <linux-kernel@vger.kernel.org>, 
	"David S. Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, 
	Jakub Kicinski <kuba@kernel.org>, John Fraker <jfraker@google.com>, Paolo Abeni <pabeni@redhat.com>, 
	Peter Zijlstra <peterz@infradead.org>, Shailend Chand <shailend@google.com>, rushilg@google.com
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On Wed, May 8, 2024 at 7:09=E2=80=AFAM Markus Elfring <Markus.Elfring@web.d=
e> wrote:
>
> =E2=80=A6
> > +++ b/drivers/net/ethernet/google/gve/gve_ethtool.c
> =E2=80=A6
> > +static int gve_get_rxnfc(struct net_device *netdev, struct ethtool_rxn=
fc *cmd, u32 *rule_locs)
> > +{
> > +     struct gve_priv *priv =3D netdev_priv(netdev);
> > +     int err =3D 0;
> > +
> > +     dev_hold(netdev);
> > +     rtnl_unlock();
> =E2=80=A6
> > +out:
> > +     rtnl_lock();
> > +     dev_put(netdev);
> > +     return err;
> > +}
> =E2=80=A6
>
> How do you think about to increase the application of scope-based resourc=
e management
> at such source code places?
>
Is the suggestion to combine dev_hold(netdev) together with
rtnl_unlock()? If so, I think there might be different usages for
using rtnl_unlock. For example, some drivers will call rtnl_unlock
after dev_close(netdev). Please correct me if I'm wrong. Thank you!

> Regards,
> Markus