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

[Salil Mehta]

Hi Leon

> -----Original Message-----
> From: Leon Romanovsky [mailto:leon@xxxxxxxxxx]
> Sent: Sunday, August 20, 2017 8:05 AM
> To: Salil Mehta
> Cc: davem@xxxxxxxxxxxxx; Zhuangyuzeng (Yisen); lipeng (Y);
> mehta.salil.lnk@xxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx; Linuxarm
> Subject: Re: [PATCH V2 net-next] net: hns3: Add support to change MTU
> in HNS3 hardware
> 
> 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.
Sure.

> 
> > 2. Initializes the supported MTU range for the netdevice.
> >
> > Signed-off-by: lipeng <lipeng321@xxxxxxxxxx>
> 
> Does "lipeng" have name and surname?
Yes, Lipeng's first name is 'Peng' and Surname is 'Li'
But it is usually spelled as 'Lipeng' in one go when referring.
This is quite usual convention with full names originating from
China. Surnames comes first, followed by the first name and they
both are inseparable while they are written as well. Therefore,
his sign-off's appear like above.

Thanks
Salil
> 
> > Signed-off-by: Salil Mehta <salil.mehta@xxxxxxxxxx>
> > ---
> > 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.
Right. Will remove this print.

Thanks
Salil
> 
> > +			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
> >
> >