Re: [dpdk-dev] [PATCH 01/29] net/ena: check if size of buffer is at least 1400B

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 3/27/20 1:17 PM, Michal Krawczyk wrote:
> Some of the ENA devices can't handle buffers which are smaller than a
> 1400B. Because of this limitation, size of the buffer is being checked
> and limited during the Rx queue setup.
> 
> If it's below the allowed value, PMD won't finish it's configuration
> successfully..
> 
> Signed-off-by: Michal Krawczyk <mk@semihalf.com>
> Reviewed-by: Igor Chauskin <igorch@amazon.com>
> Reviewed-by: Guy Tzalik <gtzalik@amazon.com>
> ---
>  drivers/net/ena/ena_ethdev.c | 12 ++++++++++++
>  drivers/net/ena/ena_ethdev.h |  1 +
>  2 files changed, 13 insertions(+)
> 
> diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
> index 665afee4f0..a8f8784a9f 100644
> --- a/drivers/net/ena/ena_ethdev.c
> +++ b/drivers/net/ena/ena_ethdev.c
> @@ -1282,6 +1282,7 @@ static int ena_rx_queue_setup(struct rte_eth_dev *dev,
>  {
>  	struct ena_adapter *adapter = dev->data->dev_private;
>  	struct ena_ring *rxq = NULL;
> +	size_t buffer_size;
>  	int i;
>  
>  	rxq = &adapter->rx_ring[queue_idx];
> @@ -1309,6 +1310,17 @@ static int ena_rx_queue_setup(struct rte_eth_dev *dev,
>  		return -EINVAL;
>  	}
>  
> +	/* ENA isn't supporting buffers smaller than 1400 bytes */
> +	buffer_size = mp->elt_size - sizeof(struct rte_mbuf) -
> +		RTE_PKTMBUF_HEADROOM;
> +	if (buffer_size < ENA_RX_BUF_MIN_SIZE) {
> +		PMD_DRV_LOG(ERR,
> +			"Unsupported size of RX buffer: %zu (min size: %d)\n",
> +			buffer_size, ENA_RX_BUF_MIN_SIZE);
> +		return -EINVAL;
> +	}
> +	printf("mempool size: %ld\n", buffer_size);

Is it debug printout left?

> +
>  	rxq->port_id = dev->data->port_id;
>  	rxq->next_to_clean = 0;
>  	rxq->next_to_use = 0;
> diff --git a/drivers/net/ena/ena_ethdev.h b/drivers/net/ena/ena_ethdev.h
> index af5eeea280..c1457defeb 100644
> --- a/drivers/net/ena/ena_ethdev.h
> +++ b/drivers/net/ena/ena_ethdev.h
> @@ -20,6 +20,7 @@
>  #define ENA_MIN_FRAME_LEN	64
>  #define ENA_NAME_MAX_LEN	20
>  #define ENA_PKT_MAX_BUFS	17
> +#define ENA_RX_BUF_MIN_SIZE	1400
>  
>  #define ENA_MIN_MTU		128
>  
>