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Date:   Wed, 12 Oct 2022 18:32:10 +0800
From:   Cai Huoqing <cai.huoqing@linux.dev>
To:     shaozhengchao <shaozhengchao@huawei.com>
Cc:     leonro@nvidia.com, caihuoqing <caihuoqing@baidu.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Qiao Ma <mqaio@linux.alibaba.com>,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: hinic: Update the range of MTU from 256 to 9600
Message-ID: <20221012103210.GA3055@chq-T47>
References: <20221012082945.10353-1-cai.huoqing@linux.dev>
 <15f63fd8-0f0e-26bc-c74e-fc7666c6ff88@huawei.com>
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On 12 10月 22 17:25:21, shaozhengchao wrote:
> 
> 
> On 2022/10/12 16:29, Cai Huoqing wrote:
> > From: caihuoqing <caihuoqing@baidu.com>
> > 
> > Hinic hardware only support MTU from 256 to 9600, so set
> > the max_mtu and min_mtu.
> > 
> > And not need to add the validity judgment when set mtu,
> > because the judgment is made in net/core: dev_validate_mtu
> > 
> > Signed-off-by: caihuoqing <caihuoqing@baidu.com>
> > ---
> >   drivers/net/ethernet/huawei/hinic/hinic_dev.h  |  3 +++
> >   drivers/net/ethernet/huawei/hinic/hinic_main.c |  3 ++-
> >   drivers/net/ethernet/huawei/hinic/hinic_port.c | 17 +----------------
> >   3 files changed, 6 insertions(+), 17 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/huawei/hinic/hinic_dev.h b/drivers/net/ethernet/huawei/hinic/hinic_dev.h
> > index a4fbf44f944c..2bbc94c0a9c1 100644
> > --- a/drivers/net/ethernet/huawei/hinic/hinic_dev.h
> > +++ b/drivers/net/ethernet/huawei/hinic/hinic_dev.h
> > @@ -22,6 +22,9 @@
> >   #define LP_PKT_CNT		64
> > +#define HINIC_MAX_MTU_SIZE		9600
Hi Shao, thanks for your reply.

I will change it in patch v2, like
"#define HINIC_MAX_MTU_SIZE (HINIC_MAX_JUMBO_FRAME_SIZE - ETH_HLEN - ETH_FCS_LEN)"
to compatible the old firmware (maybe some old cards).
> > +#define HINIC_MIN_MTU_SIZE		256
> > +
> >   enum hinic_flags {
> >   	HINIC_LINK_UP = BIT(0),
> >   	HINIC_INTF_UP = BIT(1),
> > diff --git a/drivers/net/ethernet/huawei/hinic/hinic_main.c b/drivers/net/ethernet/huawei/hinic/hinic_main.c
> > index c23ee2ddbce3..41e52f775aae 100644
> > --- a/drivers/net/ethernet/huawei/hinic/hinic_main.c
> > +++ b/drivers/net/ethernet/huawei/hinic/hinic_main.c
> > @@ -1189,7 +1189,8 @@ static int nic_dev_init(struct pci_dev *pdev)
> >   	else
> >   		netdev->netdev_ops = &hinicvf_netdev_ops;
> > -	netdev->max_mtu = ETH_MAX_MTU;
> > +	netdev->max_mtu = HINIC_MAX_MTU_SIZE;
> > +	netdev->min_mtu = HINIC_MIN_MTU_SIZE;
> >   	nic_dev = netdev_priv(netdev);
> >   	nic_dev->netdev = netdev;
> > diff --git a/drivers/net/ethernet/huawei/hinic/hinic_port.c b/drivers/net/ethernet/huawei/hinic/hinic_port.c
> > index 28ae6f1201a8..0a39c3dffa9a 100644
> > --- a/drivers/net/ethernet/huawei/hinic/hinic_port.c
> > +++ b/drivers/net/ethernet/huawei/hinic/hinic_port.c
> > @@ -17,9 +17,6 @@
> >   #include "hinic_port.h"
> >   #include "hinic_dev.h"
> > -#define HINIC_MIN_MTU_SIZE              256
> > -#define HINIC_MAX_JUMBO_FRAME_SIZE      15872
> > -
> >   enum mac_op {
> >   	MAC_DEL,
> >   	MAC_SET,
> > @@ -147,24 +144,12 @@ int hinic_port_get_mac(struct hinic_dev *nic_dev, u8 *addr)
> >    **/
> >   int hinic_port_set_mtu(struct hinic_dev *nic_dev, int new_mtu)
> >   {
> > -	struct net_device *netdev = nic_dev->netdev;
> >   	struct hinic_hwdev *hwdev = nic_dev->hwdev;
> >   	struct hinic_port_mtu_cmd port_mtu_cmd;
> >   	struct hinic_hwif *hwif = hwdev->hwif;
> >   	u16 out_size = sizeof(port_mtu_cmd);
> >   	struct pci_dev *pdev = hwif->pdev;
> > -	int err, max_frame;
> > -
> > -	if (new_mtu < HINIC_MIN_MTU_SIZE) {
> > -		netif_err(nic_dev, drv, netdev, "mtu < MIN MTU size");
> > -		return -EINVAL;
> > -	}
> > -
> > -	max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
> > -	if (max_frame > HINIC_MAX_JUMBO_FRAME_SIZE) {
> > -		netif_err(nic_dev, drv, netdev, "mtu > MAX MTU size");
> > -		return -EINVAL;
> > -	}
> > +	int err;
> >   	port_mtu_cmd.func_idx = HINIC_HWIF_FUNC_IDX(hwif);
> >   	port_mtu_cmd.mtu = new_mtu;
> 
> Hi Cai:
> 	You cannot change the maximum supported jumbo frame size.
> Because as far as I know, this is not compatible with the older
> firmware version. If you change the maximum MTU, the maximum length
> of packets received by the port will be affected with older fw. So
> donot change it.
> 
> Zhengchao Shao