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From: Yong Wang <yongwang@vmware.com>
To: Olivier Matz <olivier.matz@6wind.com>,
	Beilei Xing <beilei.xing@intel.com>,
	"jingjing.wu@intel.com" <jingjing.wu@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	Julien Meunier <julien.meunier@6wind.com>,
	 Thomas Monjalon <thomas.monjalon@6wind.com>
Subject: Re: [dpdk-dev] [PATCH v3] i40e: configure MTU
Date: Thu, 16 Jun 2016 17:51:51 +0000	[thread overview]
Message-ID: <6A233AB2-6611-44DB-80F8-2AFDCF6EB8B0@vmware.com> (raw)
In-Reply-To: <4361D496-356E-49A2-B200-E5E5D28021B3@vmware.com>

On 6/16/16, 10:40 AM, "dev on behalf of Yong Wang" <dev-bounces@dpdk.org on behalf of yongwang@vmware.com> wrote:

>On 5/16/16, 5:27 AM, "dev on behalf of Olivier Matz" <dev-bounces@dpdk.org on behalf of olivier.matz@6wind.com> wrote:
>
>>Hi Beilei,
>>
>>On 05/13/2016 10:15 AM, Beilei Xing wrote:
>>> This patch enables configuring MTU for i40e.
>>> Since changing MTU needs to reconfigure queue, stop port first
>>> before configuring MTU.
>>> 
>>> Signed-off-by: Beilei Xing <beilei.xing@intel.com>
>>> ---
>>> v3 changes:
>>>  Add frame size with extra I40E_VLAN_TAG_SIZE.
>>>  Delete i40e_dev_rx_init(pf) cause it will be called when port starts.
>>> 
>>> v2 changes:
>>>  If mtu is not within the allowed range, return -EINVAL instead of -EBUSY.
>>>  Delete rxq reconfigure cause rxq reconfigure will be finished in
>>>  i40e_dev_rx_init.
>>>    
>>>  drivers/net/i40e/i40e_ethdev.c | 34 ++++++++++++++++++++++++++++++++++
>>>  1 file changed, 34 insertions(+)
>>> 
>>> [...]
>>> +static int
>>> +i40e_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
>>> +{
>>> +	struct i40e_pf *pf = I40E_DEV_PRIVATE_TO_PF(dev->data->dev_private);
>>> +	struct rte_eth_dev_data *dev_data = pf->dev_data;
>>> +	uint32_t frame_size = mtu + ETHER_HDR_LEN
>>> +			      + ETHER_CRC_LEN + I40E_VLAN_TAG_SIZE;
>>> +	int ret = 0;
>>> +
>>> +	/* check if mtu is within the allowed range */
>>> +	if ((mtu < ETHER_MIN_MTU) || (frame_size > I40E_FRAME_SIZE_MAX))
>>> +		return -EINVAL;
>>> +
>>> +	/* mtu setting is forbidden if port is start */
>>> +	if (dev_data->dev_started) {
>>> +		PMD_DRV_LOG(ERR,
>>> +			    "port %d must be stopped before configuration\n",
>>> +			    dev_data->port_id);
>>> +		return -ENOTSUP;
>>> +	}
>>
>>I'm not convinced that ENOTSUP is the proper return value here.
>>It is usually returned when a function is not implemented, which
>>is not the case here: the function is implemented but is forbidden
>>because the port is running.
>>
>>I saw that Julien commented on your v1 that the return value should
>>be one of:
>> - (0) if successful.
>> - (-ENOTSUP) if operation is not supported.
>> - (-ENODEV) if *port_id* invalid.
>> - (-EINVAL) if *mtu* invalid.
>>
>>But I think your initial value (-EBUSY) was fine. Maybe it should be
>>added in the API instead, with the following description:
>>  (-EBUSY) if the operation is not allowed when the port is running
>
>AFAICT, the same check is not done for other drivers that implement
>the mac_set op. Wouldn’t it make more sense to have the driver disable

Correction: this should read as mtu_set.

>the port, reconfigure and re-enable it in this case, instead of returning
>error code?  If the consensus in DPDK is to have the application disable
>the port first, we need to enforce this policy across all devices and
>clearly document this behavior.
>
>>This would allow the application to take its dispositions to stop the
>>port and restart it with the proper jumbo_frame argument.
>>
>>+CC Thomas which maintains ethdev API.
>>
>>
>>Regards,
>>Olivier
>


  reply	other threads:[~2016-06-16 17:51 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-23 11:26 [dpdk-dev] [PATCH] " Beilei Xing
2016-04-26  2:00 ` Wu, Jingjing
2016-04-27 11:43 ` Julien Meunier
2016-04-27 15:01   ` Xing, Beilei
2016-04-28  3:19 ` [dpdk-dev] [PATCH V2] " Beilei Xing
2016-05-13  8:15   ` [dpdk-dev] [PATCH v3] " Beilei Xing
2016-05-16 12:27     ` Olivier Matz
2016-06-16 17:40       ` Yong Wang
2016-06-16 17:51         ` Yong Wang [this message]
2016-06-17  0:03           ` Ananyev, Konstantin
2016-06-20  4:49         ` Xing, Beilei
2016-06-20  4:59           ` Xing, Beilei
2016-06-20  8:05           ` Ananyev, Konstantin
2016-06-20 12:04             ` Xing, Beilei
2016-06-20 12:15               ` Ananyev, Konstantin
2016-06-20 12:46                 ` Xing, Beilei
2016-05-20 15:17     ` [dpdk-dev] [PATCH v4] " Beilei Xing
2016-05-23  1:33       ` Wu, Jingjing
2016-06-09 14:23         ` Bruce Richardson
2016-06-23 10:13           ` Bruce Richardson
2016-06-23 13:37             ` Xing, Beilei
2016-06-23 13:44               ` Bruce Richardson

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