Re: [dpdk-dev] [PATCH] net/ixgbevf: remove MTU setting limitation

["David Harton (dharton)" <dharton@cisco.com>]

Hi,

> -----Original Message-----
> From: Zhao1, Wei <wei.zhao1@intel.com>
> Sent: Tuesday, April 02, 2019 10:26 PM
> To: David Harton (dharton) <dharton@cisco.com>; dev@dpdk.org
> Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Ananyev, Konstantin
> <konstantin.ananyev@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>
> Subject: RE: [dpdk-dev] [PATCH] net/ixgbevf: remove MTU setting limitation
> 
> HI,
> 
> Why not add some more code
> "
> 	if (rx_conf->offloads & DEV_RX_OFFLOAD_SCATTER)
> 		dev->data->scattered_rx = 1;
> "
> 
> Into ixgbevf_dev_rx_init() to enable scatter mode when start device?

I don't think it's necessary is it?

Doesn't this code in ixgbevf_dev_rx_init() handle it?

        if (rxmode->offloads & DEV_RX_OFFLOAD_SCATTER ||
            /* It adds dual VLAN length for supporting dual VLAN */
            (rxmode->max_rx_pkt_len +
                2 * IXGBE_VLAN_TAG_SIZE) > buf_size) {
            if (!dev->data->scattered_rx)
                PMD_INIT_LOG(DEBUG, "forcing scatter mode");
            dev->data->scattered_rx = 1;
        }

Regards,
Dave

> 
> 
> Reviewed-by: Wei Zhao <wei.zhao1@intel.com>
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of David Harton
> > Sent: Wednesday, April 3, 2019 9:19 AM
> > To: dev@dpdk.org
> > Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Ananyev, Konstantin
> > <konstantin.ananyev@intel.com>; David Harton <dharton@cisco.com>
> > Subject: [dpdk-dev] [PATCH] net/ixgbevf: remove MTU setting limitation
> >
> > Currently, if requested MTU is bigger than mbuf size and scattered
> > receive is not enabled, setting MTU to that value fails.
> >
> > This patch allows setting this special MTU when device is stopped,
> > because scattered_rx will be re-configured during next port start and
> > driver may enable scattered receive according new MTU value.
> >
> > After this patch, driver may select different receive function
> > automatically after MTU set, according MTU values selected.
> >
> > Signed-off-by: David Harton <dharton@cisco.com>
> > ---
> >  drivers/net/ixgbe/ixgbe_ethdev.c | 12 +++++++-----
> >  1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c
> > b/drivers/net/ixgbe/ixgbe_ethdev.c
> > index feec85634..0b962c8db 100644
> > --- a/drivers/net/ixgbe/ixgbe_ethdev.c
> > +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
> > @@ -6346,20 +6346,22 @@ ixgbevf_dev_set_mtu(struct rte_eth_dev *dev,
> > uint16_t mtu)  {
> >  	struct ixgbe_hw *hw;
> >  	uint32_t max_frame = mtu + IXGBE_ETH_OVERHEAD;
> > -	struct rte_eth_rxmode *rx_conf = &dev->data->dev_conf.rxmode;
> > +	struct rte_eth_dev_data *dev_data = dev->data;
> >
> >  	hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
> >
> >  	if ((mtu < ETHER_MIN_MTU) || (max_frame >
> > ETHER_MAX_JUMBO_FRAME_LEN))
> >  		return -EINVAL;
> >
> > -	/* refuse mtu that requires the support of scattered packets when
> > this
> > -	 * feature has not been enabled before.
> > +	/* If device is started, refuse mtu that requires the support of
> > +	 * scattered packets when this feature has not been enabled before.
> >  	 */
> > -	if (!(rx_conf->offloads & DEV_RX_OFFLOAD_SCATTER) &&
> > +	if (dev_data->dev_started && !dev_data->scattered_rx &&
> >  	    (max_frame + 2 * IXGBE_VLAN_TAG_SIZE >
> > -	     dev->data->min_rx_buf_size - RTE_PKTMBUF_HEADROOM))
> > +	     dev->data->min_rx_buf_size - RTE_PKTMBUF_HEADROOM)) {
> > +		PMD_INIT_LOG(ERR, "Stop port first.");
> >  		return -EINVAL;
> > +	}
> >
> >  	/*
> >  	 * When supported by the underlying PF driver, use the
> > IXGBE_VF_SET_MTU
> > --
> > 2.19.1