Re: [dpdk-dev] [PATCH v2] net/igc: remove MTU setting limitation

["Guo, Jia" <jia.guo@intel.com>]

Seems that v2 is the same as v1, but v1 exposure the coding style issue. 
Anyway please add the change when update new version. Thanks.

Acked-by: Jeff Guo <jia.guo@intel.com>

> -----Original Message-----
> From: Yu, DapengX <dapengx.yu@intel.com>
> Sent: Friday, February 19, 2021 6:01 PM
> To: Guo, Jia <jia.guo@intel.com>; Wang, Haiyue <haiyue.wang@intel.com>
> Cc: dev@dpdk.org; Yu, DapengX <dapengx.yu@intel.com>; stable@dpdk.org
> Subject: [PATCH v2] net/igc: remove MTU setting limitation
> 
> From: Dapeng Yu <dapengx.yu@intel.com>
> 
> Currently, if requested MTU is bigger than mbuf size and scattered receive is
> not enabled, setting MTU to that value fails.
> 
> This patch allows setting this special MTU when device is stopped, because
> scattered_rx will be re-configured during next port start and driver may
> enable scattered receive according new MTU value.
> 
> After this patch, driver may select different receive function automatically
> after MTU set, according MTU values selected.
> 
> Fixes: a5aeb2b9e225 ("net/igc: support Rx and Tx")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Dapeng Yu <dapengx.yu@intel.com>
> ---
>  drivers/net/igc/igc_ethdev.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/igc/igc_ethdev.c b/drivers/net/igc/igc_ethdev.c index
> dbaa7a83e..0ea6e2a04 100644
> --- a/drivers/net/igc/igc_ethdev.c
> +++ b/drivers/net/igc/igc_ethdev.c
> @@ -1590,12 +1590,14 @@ eth_igc_mtu_set(struct rte_eth_dev *dev,
> uint16_t mtu)
>  		return -EINVAL;
> 
>  	/*
> -	 * refuse mtu that requires the support of scattered packets when
> -	 * this feature has not been enabled before.
> +	 * If device is started, refuse mtu that requires the support of
> +	 * scattered packets when this feature has not been enabled before.
>  	 */
> -	if (!dev->data->scattered_rx &&
> -	    frame_size > dev->data->min_rx_buf_size -
> RTE_PKTMBUF_HEADROOM)
> +	if (dev->data->dev_started && !dev->data->scattered_rx &&
> +	    frame_size > dev->data->min_rx_buf_size -
> RTE_PKTMBUF_HEADROOM) {
> +		PMD_INIT_LOG(ERR, "Stop port first.");
>  		return -EINVAL;
> +	}
> 
>  	rctl = IGC_READ_REG(hw, IGC_RCTL);
> 
> --
> 2.27.0