Re: [dpdk-dev] [PATCH] vhost PMD: Fix wrong handling of maximum value of rx/tx queues

["Loftus, Ciara" <ciara.loftus@intel.com>]

> 
> Currently, the maximum value of rx/tx queueus are kept by EAL. But,
> the value are used like below different meanings in vhost PMD.
>  - The maximum value of current enabled queues.
>  - The maximum value of current supported queues.
> 
> This wrong double meaning will cause an issue like below steps.
> 
> * Invoke application with below option.
>   --vdev 'eth_vhost0,iface=<socket path>,queues=4'
> * Configure queues like below.
>   rte_eth_dev_configure(portid, 2, 2, ...);
> * Configure queues again like below.
>   rte_eth_dev_configure(portid, 4, 4, ...);
> 
> The second rte_eth_dev_configure() will be failed because both
> the maximum value of current enabled queues and supported queues
> will be '2' after calling first rte_eth_dev_configure().
> 
> To fix the issue, the patch prepare one more variable to keep the
> number of maximum supported queues in vhost PMD.
> 
> Signed-off-by: Tetsuya Mukawa <mukawa@igel.co.jp>
> ---
>  drivers/net/vhost/rte_eth_vhost.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/vhost/rte_eth_vhost.c
> b/drivers/net/vhost/rte_eth_vhost.c
> index 6b9d287..5fd8c70 100644
> --- a/drivers/net/vhost/rte_eth_vhost.c
> +++ b/drivers/net/vhost/rte_eth_vhost.c
> @@ -88,6 +88,7 @@ struct vhost_queue {
>  struct pmd_internal {
>  	char *dev_name;
>  	char *iface_name;
> +	uint16_t max_queues;
> 
>  	volatile uint16_t once;
>  };
> @@ -555,11 +556,19 @@ static void
>  eth_dev_info(struct rte_eth_dev *dev,
>  	     struct rte_eth_dev_info *dev_info)
>  {
> +	struct pmd_internal *internal;
> +
> +	internal = dev->data->dev_private;
> +	if (internal == NULL) {
> +		RTE_LOG(ERR, PMD, "Invalid device specified\n");
> +		return;
> +	}
> +
>  	dev_info->driver_name = drivername;
>  	dev_info->max_mac_addrs = 1;
>  	dev_info->max_rx_pktlen = (uint32_t)-1;
> -	dev_info->max_rx_queues = dev->data->nb_rx_queues;
> -	dev_info->max_tx_queues = dev->data->nb_tx_queues;
> +	dev_info->max_rx_queues = internal->max_queues;
> +	dev_info->max_tx_queues = internal->max_queues;
>  	dev_info->min_rx_bufsize = 0;
>  }
> 
> @@ -751,6 +760,7 @@ eth_dev_vhost_create(const char *name, char
> *iface_name, int16_t queues,
>  	memmove(data->name, eth_dev->data->name, sizeof(data-
> >name));
>  	data->nb_rx_queues = queues;
>  	data->nb_tx_queues = queues;
> +	internal->max_queues = queues;
>  	data->dev_link = pmd_link;
>  	data->mac_addrs = eth_addr;
> 
> --
> 2.1.4

Hi Tetsuya,

Thanks again for the patch.

Acked-by: Ciara Loftus <ciara.loftus@intel.com>

Thanks,
Ciara