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Subject: Re: [PATCH v2] net: qrtr: Expose tunneling endpoint to user space
To:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        "David S. Miller" <davem@davemloft.net>
Cc:     linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        linux-arm-msm@vger.kernel.org
References: <20180423214653.10016-1-bjorn.andersson@linaro.org>
From:   Chris Lew <clew@codeaurora.org>
Message-ID: <46fe45d8-6f3a-5bed-c02c-6e61ba1175d2@codeaurora.org>
Date:   Thu, 26 Apr 2018 15:29:53 -0700
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On 4/23/2018 2:46 PM, Bjorn Andersson wrote:
> This implements a misc character device named "qrtr-tun" for the purpose
> of allowing user space applications to implement endpoints in the qrtr
> network.
> 
> This allows more advanced (and dynamic) testing of the qrtr code as well
> as opens up the ability of tunneling qrtr over a network or USB link.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Acked-by: Chris Lew <clew@codeaurora.org>

> +static ssize_t qrtr_tun_read_iter(struct kiocb *iocb, struct iov_iter *to)
> +{
> +	struct file *filp = iocb->ki_filp;
> +	struct qrtr_tun *tun = filp->private_data;
> +	struct sk_buff *skb;
> +	int count;
> +
> +	while (!(skb = skb_dequeue(&tun->queue))) {
> +		if (filp->f_flags & O_NONBLOCK)
> +			return -EAGAIN;
> +
> +		/* Wait until we get data or the endpoint goes away */
> +		if (wait_event_interruptible(tun->readq,
> +					     !skb_queue_empty(&tun->queue)))
> +			return -ERESTARTSYS;
> +	}
> +
> +	count = min_t(size_t, iov_iter_count(to), skb->len);
> +	if (copy_to_iter(skb->data, count, to) != count)
> +		count = -EFAULT;
> +
> +	kfree_skb(skb);

Is it better to use consume_skb() since this is the expected behavior path?

> +
> +	return count;
> +}
> +

Thanks,
Chris

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