Subject: Re: [PATCH V2 net-next] net: hns3: Add support to change MTU in HNS3 hardware

From: Leon Romanovsky <[email-masked]>
Date: Sun, 20 Aug 2017 10:05:24 +0300

On Fri, Aug 18, 2017 at 05:57:59PM +0100, Salil Mehta wrote:
> This patch adds the following support to the HNS3 driver:
> 1. Support to change the Maximum Transmission Unit of a
>    of a port in the HNS NIC hardware .

Extra space before dot.

> 2. Initializes the supported MTU range for the netdevice.
>
> Signed-off-by: lipeng <[email-masked]>

Does "lipeng" have name and surname?

> Signed-off-by: Salil Mehta <[email-masked]>
> ---
> PATCH V2: Addresses comments given by Andrew Lunn
>           1. https://lkml.org/lkml/2017/8/18/282
> PATCH V1: Initial Submit
> ---
>  .../net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.c | 38 ++++++++++++++++++++++
>  .../net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.h |  1 +
>  2 files changed, 39 insertions(+)
>
> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.c
> index e731f87..d905ea1 100644
> --- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.c
> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.c
> @@ -1278,11 +1278,46 @@ static int hns3_ndo_set_vf_vlan(struct net_device *netdev, int vf, u16 vlan,
>  	return ret;
>  }
>
> +static int hns3_nic_change_mtu(struct net_device *netdev, int new_mtu)
> +{
> +	struct hns3_nic_priv *priv = netdev_priv(netdev);
> +	struct hnae3_handle *h = priv->ae_handle;
> +	bool if_running = netif_running(netdev);
> +	int ret;
> +
> +	if (!h->ae_algo->ops->set_mtu)
> +		return -ENOTSUPP;
> +
> +	/* if this was called with netdev up then bring netdevice down */
> +	if (if_running) {
> +		(void)hns3_nic_net_stop(netdev);
> +		msleep(100);
> +	}
> +
> +	ret = h->ae_algo->ops->set_mtu(h, new_mtu);
> +	if (ret) {
> +		netdev_err(netdev, "failed to change MTU in hardware %d\n",
> +			   ret);
> +		return ret;
> +	}
> +
> +	/* if the netdev was running earlier, bring it up again */
> +	if (if_running) {
> +		if (hns3_nic_net_open(netdev)) {
> +			netdev_err(netdev, "MTU, couldnt up netdev again\n");

"couldnt" -> "couldn't"

and you don't actually need this print.
If the function hns3_nic_net_open fails, you will print this error there.

> +			ret = -EINVAL;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
>  static const struct net_device_ops hns3_nic_netdev_ops = {
>  	.ndo_open		= hns3_nic_net_open,
>  	.ndo_stop		= hns3_nic_net_stop,
>  	.ndo_start_xmit		= hns3_nic_net_xmit,
>  	.ndo_set_mac_address	= hns3_nic_net_set_mac_address,
> +	.ndo_change_mtu		= hns3_nic_change_mtu,
>  	.ndo_set_features	= hns3_nic_set_features,
>  	.ndo_get_stats64	= hns3_nic_get_stats64,
>  	.ndo_setup_tc		= hns3_nic_setup_tc,
> @@ -2752,6 +2787,9 @@ static int hns3_client_init(struct hnae3_handle *handle)
>  		goto out_reg_netdev_fail;
>  	}
>
> +	/* MTU range: (ETH_MIN_MTU(kernel default) - 9706) */
> +	netdev->max_mtu = HNS3_MAX_MTU - (ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN);
> +
>  	return ret;
>
>  out_reg_netdev_fail:
> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.h b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.h
> index a6e8f15..7e87461 100644
> --- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.h
> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.h
> @@ -76,6 +76,7 @@ enum hns3_nic_state {
>  #define HNS3_RING_NAME_LEN			16
>  #define HNS3_BUFFER_SIZE_2048			2048
>  #define HNS3_RING_MAX_PENDING			32768
> +#define HNS3_MAX_MTU				9728
>
>  #define HNS3_BD_SIZE_512_TYPE			0
>  #define HNS3_BD_SIZE_1024_TYPE			1
> --
> 2.7.4
>
>