Re: [PATCH net-next v2 1/2] net: use two lockdep classes for the netdev instance lock

[Jakub Kicinski <kuba@kernel.org>]

On Sat, 26 Sep 2026 09:08:16 +0200 Eric Dumazet wrote:
> >         mutex_init(&dev->lock);
> > +       /* see also netdev_set_instance_lock_class() */
> > +       lock_set_cmp_fn(&dev->lock, netdev_lock_cmp_fn, NULL);
> >         netif_rx_mode_init(dev);
> >
> >         dev->priv_flags = IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM;  
> 
> Some virttual drivers (like  tun and wireguard) do not use yet
> netdev_lockdep_set_classes(),
> I'm not sure if they eventually will.
> 
> We might ease their future request_ops_lock = true conversion by calling
> netdev_set_instance_lock_class(dev) directly inside register_netdevice()
> 
> -> No EXPORT_SYMBOL_GPL(netdev_set_instance_lock_class) would be needed.  
> In fact netdev_set_instance_lock_class couldd be static in net/core/dev.c

Ack, maybe I lazied out on this one a little. I wasn't sure what the
consequences are of not setting the class before the first lock use.
I _think_ I've seen a splat at some point when I did that.

I will investigate further if I need to respin