Re: [PATCH net] tun/tap & vhost-net: make qdisc backpressure opt-in via IFF_BACKPRESSURE

[Simon Schippers]

On 7/4/26 13:20, Simon Schippers wrote:
> @@ -2893,8 +2899,19 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
>  	/* Make sure persistent devices do not get stuck in
>  	 * xoff state.
>  	 */
> -	if (netif_running(tun->dev))
> -		netif_tx_wake_all_queues(tun->dev);
> +	if (netif_running(tun->dev)) {
> +		for (int i = 0; i < tun->numqueues; i++) {
> +			struct tun_file *i_tfile;
> +
> +			i_tfile = rtnl_dereference(tun->tfiles[i]);
> +			spin_lock_bh(&i_tfile->tx_ring.consumer_lock);
> +			spin_lock(&i_tfile->tx_ring.producer_lock);
> +			netif_wake_subqueue(tun->dev, i_tfile->queue_index);
> +			i_tfile->cons_cnt = 0;
> +			spin_unlock(&i_tfile->tx_ring.producer_lock);
> +			spin_unlock_bh(&i_tfile->tx_ring.consumer_lock);
> +		}
> +	}

I think Sashiko [1] is right. I forgot to wake the disabled queues.

I will post a v2.

[1] Link: https://sashiko.dev/#/patchset/20260704112058.95421-1-simon.schippers%40tu-dortmund.de