From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-next V2 3/3] tun: rx batching
Date: Thu, 29 Dec 2016 11:35:06 -0500 (EST)
Message-ID: <20161229.113506.1833529555874695164.davem@davemloft.net>
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From: Jason Wang <jasowang@redhat.com>
Date: Wed, 28 Dec 2016 16:09:31 +0800

> +	spin_lock(&queue->lock);
> +	qlen = skb_queue_len(queue);
> +	if (qlen > rx_batched)
> +		goto drop;
> +	__skb_queue_tail(queue, skb);
> +	if (!more || qlen + 1 > rx_batched) {
> +		__skb_queue_head_init(&process_queue);
> +		skb_queue_splice_tail_init(queue, &process_queue);
> +		rcv = true;
> +	}
> +	spin_unlock(&queue->lock);

Since you always clear the 'queue' when you insert the skb that hits
the limit, I don't see how the "goto drop" path can be possibly taken.