Re: [PATCH v2] net/ixgbe: fix VLAN strip setting fail for per port

["Dai, Wei" <wei.dai@intel.com>]

> -----Original Message-----
> From: Zhang, Qi Z
> Sent: Friday, May 18, 2018 8:37 PM
> To: Dai, Wei <wei.dai@intel.com>; Wu, Yanglong
> <yanglong.wu@intel.com>; dev@dpdk.org
> Subject: RE: [PATCH v2] net/ixgbe: fix VLAN strip setting fail for per port
> 
> Hi Daiwei:
> 
> > -----Original Message-----
> > From: Dai, Wei
> > Sent: Friday, May 18, 2018 7:07 PM
> > To: Zhang, Qi Z <qi.z.zhang@intel.com>; Wu, Yanglong
> > <yanglong.wu@intel.com>; dev@dpdk.org
> > Subject: RE: [PATCH v2] net/ixgbe: fix VLAN strip setting fail for per
> > port
> >
> > > -----Original Message-----
> > > From: Zhang, Qi Z
> > > Sent: Friday, May 18, 2018 3:46 PM
> > > To: Wu, Yanglong <yanglong.wu@intel.com>; dev@dpdk.org
> > > Cc: Dai, Wei <wei.dai@intel.com>
> > > Subject: RE: [PATCH v2] net/ixgbe: fix VLAN strip setting fail for
> > > per port
> > >
> > > > -----Original Message-----
> > > > From: Wu, Yanglong
> > > > Sent: Friday, May 18, 2018 3:24 PM
> > > > To: dev@dpdk.org
> > > > Cc: Zhang, Qi Z <qi.z.zhang@intel.com>; Dai, Wei
> > > > <wei.dai@intel.com>; Wu, Yanglong <yanglong.wu@intel.com>
> > > > Subject: [PATCH v2] net/ixgbe: fix VLAN strip setting fail for per
> > > > port
> > > >
> > > > rxq->offload should synchronize with dev_conf
> > > >
> > > > Fixes: 860a94d3c692 ("net/ixgbe: support VLAN strip per queue
> > > > offloading in
> > > > VF")
> > > > Signed-off-by: Yanglong Wu <yanglong.wu@intel.com>
> > >
> > > Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> >
> > The release date is coming soon.
> > Sorry, I have to NACK it.
> > VLAN strip is per-queue feature,
> > If it is disabled on port level, it still can be enabled on queue level.
> > So the else branches still should be removed.
> 
> Remove the else branch will not disable all queues if some queue is enabled
> at queue configure level, I think this is not user expected.
> The purpose of i40e_vlan_offload_set here is to disable all queue's vlan strip,
> though vlan strip is per queue offload and some queue may be enabled at
> queue configure level, I don't know why we can't disable them in this
> function.
> 
> Thanks
> Qi

As VLAN_STRIP has already been advertised to per-queue offloading on ixgbe 82599/X540/X550.
The else branches will break this per-queue feature.

The issues is from the testpmd command "vlan set strip on <port_id>"
Which is meant to enable/disable VLAN_STRIP on whole port on the fly. 
The call stack is as follows:
rx_vlan_strip_set(portid_t port_id, int on)
	rte_eth_dev_set_vlan_offload(port_id, vlan_offload); //modify dev->data->dev_conf.rxmode.offloads
		dev->dev_ops->vlan_offload_set(dev, mask)
			ixgbe_vlan_offload_set(dev, mask)
				ixgbe_vlan_hw_strip_config(struct rte_eth_dev *dev)
					ixgbe_vlan_hw_strip_bitmap_set(struct rte_eth_dev *dev, uint16_t queue, bool on)

As the VLAN_STRIP is per-queue capability, ixgbe_vlan_hw_strip_config() only get it from rxq->offloads which hasn't been update in rte_eth_dev_set_vlan_offload(port_id, vlan_offload);

And the ixgbe_vlan_offload_set() is also be called by ixgbe_dev_start() which is normal called after dev_configure() and queue_setup().

These are 2 different path to config VLAN_STRIP.
So we can add a function ixgbe_vlan_offload_config() to let them go different way as follows:

dev->dev_ops->vlan_offload_set(dev, mask) -> point to new function ixgbe_vlan_offload_config()
		ixgbe_vlan_offload_config(dev, mask) {
			if vlan_strip is configured on whole port {
				update dev->data->dev_conf.rxmode.offloads
				update rxq->offloads on all queues
			}
			Ixgbe_vlan_offload_set()
		}

Ixgbe_dev_start()
	ixgbe_vlan_offload_set()