Re: [dpdk-dev] [PATCH] net/i40e: fix modifying the number of queues

["Zhang, AlvinX" <alvinx.zhang@intel.com>]

Hi Jia,

> -----Original Message-----
> From: Guo, Jia
> Sent: Sunday, June 21, 2020 9:36 PM
> To: Zhang, AlvinX <alvinx.zhang@intel.com>; dev@dpdk.org
> Cc: stable@dpdk.org; Xing, Beilei <beilei.xing@intel.com>; Jiang, MaoX
> <maox.jiang@intel.com>
> Subject: Re: [PATCH] net/i40e: fix modifying the number of queues
> 
> hi, alvin
> 
> On 6/10/2020 8:07 PM, alvinx.zhang@intel.com wrote:
> > From: Alvin Zhang <alvinx.zhang@intel.com>
> >
> > For the newly created VF, if the number of qps is greater than 4 at
> > startup, it may fail to start. This patch updates the API
> > `i40evf_dev_configure`.
> 
> 
> Could you explicit explain why it limit to 4 qps, and more detail about below
> code change with the purpose of the patch.

For each VF, the kernel PF driver assign 4 qps when the VF be created.

> 
> 
> > Fixes: c48eb308ed13 ("net/i40e: support VF request more queues")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Alvin Zhang <alvinx.zhang@intel.com>
> > ---
> >   drivers/net/i40e/i40e_ethdev_vf.c | 32 ++++++++++++++++++++++++---
> -----
> >   1 file changed, 24 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/net/i40e/i40e_ethdev_vf.c
> b/drivers/net/i40e/i40e_ethdev_vf.c
> > index bb5d28a..7500e0a 100644
> > --- a/drivers/net/i40e/i40e_ethdev_vf.c
> > +++ b/drivers/net/i40e/i40e_ethdev_vf.c
> > @@ -1082,13 +1082,10 @@ static int i40evf_dev_xstats_get(struct
> rte_eth_dev *dev,
> >   	args.out_buffer = vf->aq_resp;
> >   	args.out_size = I40E_AQ_BUF_SZ;
> >
> > -	rte_eal_alarm_cancel(i40evf_dev_alarm_handler, dev);
> 
> 
> Why interrupt handler is no need to cancel here and more why this change
> is related with this patch according with the commit log?

Here, the handler has been cancecled by the caller.

> 
> 
> >   	err = i40evf_execute_vf_cmd(dev, &args);
> >   	if (err)
> >   		PMD_DRV_LOG(ERR, "fail to execute command
> OP_REQUEST_QUEUES");
> >
> > -	rte_eal_alarm_set(I40EVF_ALARM_INTERVAL,
> > -			  i40evf_dev_alarm_handler, dev);
> >   	return err;
> >   }
> >
> > @@ -1516,7 +1513,7 @@ static int i40evf_dev_xstats_get(struct
> rte_eth_dev *dev,
> >   	hw->bus.device = pci_dev->addr.devid;
> >   	hw->bus.func = pci_dev->addr.function;
> >   	hw->hw_addr = (void *)pci_dev->mem_resource[0].addr;
> > -	hw->adapter_stopped = 0;
> > +	hw->adapter_stopped = 1;
> 
> 
> Why it should be set stopped when init dev?

The Device has not been started until the API ` i40evf_dev_start ` been called.
Here we just initiate the device, so it should be set to 1. 

> 
> 
> >   	hw->adapter_closed = 0;
> >
> >   	/* Pass the information to the rte_eth_dev_close() that it should
> also
> > @@ -1612,16 +1609,35 @@ static int eth_i40evf_pci_remove(struct
> rte_pci_device *pci_dev)
> >   	ad->tx_vec_allowed = true;
> >
> >   	if (num_queue_pairs > vf->vsi_res->num_queue_pairs) {
> > -		int ret = 0;
> > +		struct i40e_hw *hw;
> > +		int ret;
> >
> > +		hw  = I40E_DEV_PRIVATE_TO_HW(dev->data->dev_private);
> >   		PMD_DRV_LOG(INFO, "change queue pairs from %u to %u",
> >   			    vf->vsi_res->num_queue_pairs,
> num_queue_pairs);
> > +		if (hw->adapter_stopped == 0) {
> > +			PMD_DRV_LOG(WARNING, "Device must be
> stopped first!");
> > +			return -EINVAL;
> > +		}
> > +
> > +		rte_eal_alarm_cancel(i40evf_dev_alarm_handler, dev);
> >   		ret = i40evf_request_queues(dev, num_queue_pairs);
> > -		if (ret != 0)
> > +		if (ret)
> >   			return ret;
> >
> > -		ret = i40evf_dev_reset(dev);
> > -		if (ret != 0)
> > +		/*
> > +		 * The device must be reinitiated after queue resources
> > +		 * changed
> > +		 */
> 
> 
> Should you check below part is reinitialize process according to exist
> dev_close and dev_init.

Yes, it stops and reinitializes the device , but if call the dev_close to do, some process is no needed and should report errors.

> 
> 
> > +		i40e_shutdown_adminq(hw);
> > +		i40evf_disable_irq0(hw);
> > +		rte_free(vf->vf_res);
> > +		vf->vf_res = NULL;
> > +		rte_free(vf->aq_resp);
> > +		vf->aq_resp = NULL;
> > +
> > +		ret = i40evf_dev_init(dev);
> > +		if (ret)
> >   			return ret;
> >   	}
> >