Re: [dpdk-dev] [PATCH] ethdev: fix device info getting

["Lu, Wenzhuo" <wenzhuo.lu@intel.com>]

Hi Andrew,

> -----Original Message-----
> From: Andrew Rybchenko [mailto:arybchenko@solarflare.com]
> Sent: Thursday, July 12, 2018 4:06 PM
> To: Lu, Wenzhuo <wenzhuo.lu@intel.com>; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] ethdev: fix device info getting
> 
> On 12.07.2018 08:27, Wenzhuo Lu wrote:
> > The device information cannot be gotten correctly before the
> > configuration is set. Because on some NICs the information has
> > dependence on the configuration.
> >
> > Fixes: 3be82f5cc5e3 ("ethdev: support PMD-tuned Tx/Rx parameters")
> > Signed-off-by: Wenzhuo Lu <wenzhuo.lu@intel.com>
> > ---
> >   lib/librte_ethdev/rte_ethdev.c | 47 +++++++++++++++++++++------------------
> ---
> >   1 file changed, 24 insertions(+), 23 deletions(-)
> >
> > diff --git a/lib/librte_ethdev/rte_ethdev.c
> > b/lib/librte_ethdev/rte_ethdev.c index 3d556a8..9d60bea 100644
> > --- a/lib/librte_ethdev/rte_ethdev.c
> > +++ b/lib/librte_ethdev/rte_ethdev.c
> > @@ -1017,28 +1017,6 @@ struct rte_eth_dev *
> >
> >   	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
> >
> > -	dev = &rte_eth_devices[port_id];
> > -
> > -	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_infos_get, -
> ENOTSUP);
> > -	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_configure, -
> ENOTSUP);
> > -
> > -	rte_eth_dev_info_get(port_id, &dev_info);
> > -
> > -	/* If number of queues specified by application for both Rx and Tx is
> > -	 * zero, use driver preferred values. This cannot be done individually
> > -	 * as it is valid for either Tx or Rx (but not both) to be zero.
> > -	 * If driver does not provide any preferred valued, fall back on
> > -	 * EAL defaults.
> > -	 */
> > -	if (nb_rx_q == 0 && nb_tx_q == 0) {
> > -		nb_rx_q = dev_info.default_rxportconf.nb_queues;
> > -		if (nb_rx_q == 0)
> > -			nb_rx_q = RTE_ETH_DEV_FALLBACK_RX_NBQUEUES;
> > -		nb_tx_q = dev_info.default_txportconf.nb_queues;
> > -		if (nb_tx_q == 0)
> > -			nb_tx_q = RTE_ETH_DEV_FALLBACK_TX_NBQUEUES;
> > -	}
> > -
> >   	if (nb_rx_q > RTE_MAX_QUEUES_PER_PORT) {
> >   		RTE_ETHDEV_LOG(ERR,
> >   			"Number of RX queues requested (%u) is greater
> than max
> > supported(%d)\n", @@ -1053,6 +1031,11 @@ struct rte_eth_dev *
> >   		return -EINVAL;
> >   	}
> >
> > +	dev = &rte_eth_devices[port_id];
> > +
> > +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_infos_get, -
> ENOTSUP);
> > +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_configure, -
> ENOTSUP);
> > +
> >   	if (dev->data->dev_started) {
> >   		RTE_ETHDEV_LOG(ERR,
> >   			"Port %u must be stopped to allow configuration\n",
> @@ -1060,8
> > +1043,26 @@ struct rte_eth_dev *
> >   		return -EBUSY;
> >   	}
> >
> > -	/* Copy the dev_conf parameter into the dev structure */
> > +	/* Copy the dev_conf parameter into the dev structure,
> > +	 * then get the info.
> > +	 */
> >   	memcpy(&dev->data->dev_conf, &local_conf,
> > sizeof(dev->data->dev_conf));
> > +	rte_eth_dev_info_get(port_id, &dev_info);
> > +
> > +	/* If number of queues specified by application for both Rx and Tx is
> > +	 * zero, use driver preferred values. This cannot be done individually
> > +	 * as it is valid for either Tx or Rx (but not both) to be zero.
> > +	 * If driver does not provide any preferred valued, fall back on
> > +	 * EAL defaults.
> > +	 */
> > +	if (nb_rx_q == 0 && nb_tx_q == 0) {
> > +		nb_rx_q = dev_info.default_rxportconf.nb_queues;
> > +		if (nb_rx_q == 0)
> > +			nb_rx_q = RTE_ETH_DEV_FALLBACK_RX_NBQUEUES;
> > +		nb_tx_q = dev_info.default_txportconf.nb_queues;
> > +		if (nb_tx_q == 0)
> > +			nb_tx_q = RTE_ETH_DEV_FALLBACK_TX_NBQUEUES;
> 
> Values assigned in this branch are not checked against
> RTE_MAX_QUEUES_PER_PORT and RTE_MAX_QUEUES_PER_PORT now
O, I supposed the default values cannot be larger than RTE_MAX_QUEUES_PER_PORT. But, yes, it's each NIC's decision. My assumption can be wrong. I'll move the check down here.

> 
> > +	}
> >
> >   	/*
> >   	 * Check that the numbers of RX and TX queues are not greater