On 1/30/2017 2:34 PM, Wiles, Keith wrote:

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On Jan 30, 2017, at 5:00 AM, Yigit, Ferruh [off-list ref] wrote:

On 1/29/2017 2:12 AM, Keith Wiles wrote:

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The tap driver setup both rx and tx file descriptors when the
rte_eth_rx_queue_setup() causing the tx to be closed when tx setup
was called.

Can you please describe the problem more.
Without this patch rx->fd == tx->fd, with this patch rx and tx has
different file descriptors.

Let me look at this more, I am getting the same FD for both. Must be something else going on.

After patch, tun_alloc() called twice, one for Rx_q and other for Tx_q.
And tun_alloc does open() to "/dev/net/tun", I expect they get different
file descriptors.

And if they have same FD, won't this cause same problem,
rx_queue_setup() will close the FD, if Tx_q has same FD it will have
invalid descriptor.

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What was the wrong with rx and tx having same fd?

As far as I can see, rte_eth_rx_queue_setup() won't close tx->fd, that
function will do nothing if rx or tx has valid fd.

The rte_eth_rx_queue_setup() look at line 1146 if rxq has a value then release it, which happens on both Rx/Tx code

	rxq = dev->data->rx_queues;
	if (rxq[rx_queue_id]) {
		RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_release,
					-ENOTSUP);
		(*dev->dev_ops->rx_queue_release)(rxq[rx_queue_id]);
		rxq[rx_queue_id] = NULL;
	}

Got it thanks, I missed (relatively new) above code piece.

	if (rx_conf == NULL)
		rx_conf = &dev_info.default_rxconf;

	ret = (*dev->dev_ops->rx_queue_setup)(dev, rx_queue_id, nb_rx_desc,
					      socket_id, rx_conf, mp);

quoted

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Signed-off-by: Keith Wiles <redacted>

<...>

Regards,
Keith