Re: [dpdk-dev] [PATCH v2 2/3] ring: remove duplicate fields in internal data struct

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Feb 18, 2016 at 11:26:42AM +0000, Ferruh Yigit wrote:
> 1- Remove duplicate nb_rx/tx_queues fields from internals
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
>  drivers/net/ring/rte_eth_ring.c | 57 ++++++++++++++++++-----------------------
>  1 file changed, 25 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/net/ring/rte_eth_ring.c b/drivers/net/ring/rte_eth_ring.c
> index d92b088..fd87999 100644
> --- a/drivers/net/ring/rte_eth_ring.c
> +++ b/drivers/net/ring/rte_eth_ring.c
> @@ -59,9 +59,6 @@ struct ring_queue {
>  };
>  
>  struct pmd_internals {
> -	unsigned nb_rx_queues;
> -	unsigned nb_tx_queues;
> -
>  	struct ring_queue rx_ring_queues[RTE_PMD_RING_MAX_RX_RINGS];
>  	struct ring_queue tx_ring_queues[RTE_PMD_RING_MAX_TX_RINGS];
>  
> @@ -138,7 +135,7 @@ eth_dev_set_link_up(struct rte_eth_dev *dev)
>  }
>  
>  static int
> -eth_rx_queue_setup(struct rte_eth_dev *dev,uint16_t rx_queue_id,
> +eth_rx_queue_setup(struct rte_eth_dev *dev, uint16_t rx_queue_id,
>  				    uint16_t nb_rx_desc __rte_unused,
>  				    unsigned int socket_id __rte_unused,
>  				    const struct rte_eth_rxconf *rx_conf __rte_unused,
> @@ -165,40 +162,39 @@ static void
>  eth_dev_info(struct rte_eth_dev *dev,
>  		struct rte_eth_dev_info *dev_info)
>  {
> -	struct pmd_internals *internals = dev->data->dev_private;
>  	dev_info->driver_name = drivername;
>  	dev_info->max_mac_addrs = 1;
>  	dev_info->max_rx_pktlen = (uint32_t)-1;
> -	dev_info->max_rx_queues = (uint16_t)internals->nb_rx_queues;
> -	dev_info->max_tx_queues = (uint16_t)internals->nb_tx_queues;
> +	dev_info->max_rx_queues = dev->data->nb_rx_queues;
> +	dev_info->max_tx_queues = dev->data->nb_tx_queues;

I'm still not convined this is correct. What happens if a ring PMD is created
with 16 queues (i.e. backed by 16 rings), and then the user uses
rte_eth_dev_configure to only actually use 4 queues. The fact that the internal
array still has 16 queues will be lost, and the device will only ever report
4 as the max number it can support.

Regards,
/Bruce