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

[Leon Romanovsky]

On Sun, Aug 20, 2017 at 02:35:58PM +0000, Salil Mehta wrote:
> 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.

Thank you for the explanation.

>
> 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
> > >
> > >

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