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

[Jeff Guo <jia.guo@intel.com>]

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.


> 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?


>   	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?


>   	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.


> +		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;
>   	}
>