Re: [PATCH v9 net-next 3/5] psp: add a new netdev event for dev unregister

[Daniel Zahka <daniel.zahka@gmail.com>]

On 3/30/26 6:31 PM, Wei Wang wrote:
> +static bool psp_notifier_registered;
> +
> +/**
> + * psp_attach_netdev_notifier() - register netdev notifier on first use
> + *
> + * Register the netdevice notifier when the first device association
> + * is created. In many installations no associations will be created and
> + * the notifier won't be needed.
> + *
> + * Must be called without psd->lock held, due to lock ordering:
> + * rtnl_lock -> psd->lock (the notifier callback runs under rtnl_lock
> + * and takes psd->lock).
> + */
> +void psp_attach_netdev_notifier(void)
> +{
> +	if (READ_ONCE(psp_notifier_registered))
> +		return;
> +
> +	mutex_lock(&psp_devs_lock);
> +	if (!psp_notifier_registered) {
> +		if (!register_netdevice_notifier(&psp_netdev_notifier))
> +			WRITE_ONCE(psp_notifier_registered, true);
> +	}
> +	mutex_unlock(&psp_devs_lock);
> +}
...
>   
> +int psp_device_get_locked_dev_assoc(const struct genl_split_ops *ops,
> +				    struct sk_buff *skb, struct genl_info *info)
> +{
> +	psp_attach_netdev_notifier();
> +
> +	return __psp_device_get_locked(ops, skb, info, false);
> +}


 From an AI review, but seems plausible to me:

psp_device_get_locked_dev_assoc() will proceed even in the path where 
register_netdevice_notifier() and psp_notifier_registered stays false.