[dpdk-dev] [PATCH] net/ixgbe: clean up rte_eth_dev_info_get

[Ferruh Yigit]

On 2/3/2017 6:50 AM, Lu, Wenzhuo wrote:
> Hi Ferruh,
> 
>> -----Original Message-----
>> From: Yigit, Ferruh
>> Sent: Monday, January 30, 2017 8:16 PM
>> To: Bie, Tiwei; Lu, Wenzhuo
>> Cc: dev at dpdk.org
>> Subject: Re: [dpdk-dev] [PATCH] net/ixgbe: clean up rte_eth_dev_info_get
>>
>> On 1/25/2017 5:24 AM, Tiwei Bie wrote:
>>> On Wed, Jan 25, 2017 at 01:13:32PM +0800, Lu, Wenzhuo wrote:
>>>> Hi Tiwei,
>>>>
>>>>> -----Original Message-----
>>>>> From: Bie, Tiwei
>>>>> Sent: Wednesday, January 25, 2017 11:17 AM
>>>>> To: Lu, Wenzhuo
>>>>> Cc: dev at dpdk.org
>>>>> Subject: Re: [dpdk-dev] [PATCH] net/ixgbe: clean up
>>>>> rte_eth_dev_info_get
>>>>>
>>>>> On Wed, Jan 25, 2017 at 10:39:22AM +0800, Wenzhuo Lu wrote:
>>>>>> It'not appropriate to call rte_eth_dev_info_get in PMD, as
>>>>>> rte_eth_dev_info_get need to get info from PMD.
>>>>>> Remove rte_eth_dev_info_get from PMD code and get the info directly.
>>>>>>
>>>>>> Signed-off-by: Wenzhuo Lu <wenzhuo.lu at intel.com>
>>>>>> ---
>>>>>>  drivers/net/ixgbe/ixgbe_ethdev.c | 144
>>>>>> ++++++++++++++++++---------------------
>>>>>>  1 file changed, 68 insertions(+), 76 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c
>>>>>> b/drivers/net/ixgbe/ixgbe_ethdev.c
>>>>>> index 64ce55a..f14a68b 100644
>>>>>> --- a/drivers/net/ixgbe/ixgbe_ethdev.c
>>>>>> +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
>>>>>> @@ -4401,17 +4401,17 @@ static int
>>>>> ixgbevf_dev_xstats_get_names(__rte_unused struct rte_eth_dev *dev,
>>>>>>  	int rar_entry;
>>>>>>  	uint8_t *new_mac = (uint8_t *)(mac_addr);
>>>>>>  	struct rte_eth_dev *dev;
>>>>>> -	struct rte_eth_dev_info dev_info;
>>>>>> +	struct rte_pci_device *pci_dev;
>>>>>>
>>>>>>  	RTE_ETH_VALID_PORTID_OR_ERR_RET(port, -ENODEV);
>>>>>>
>>>>>>  	dev = &rte_eth_devices[port];
>>>>>> -	rte_eth_dev_info_get(port, &dev_info);
>>>>>> +	pci_dev = IXGBE_DEV_TO_PCI(dev);
>>>>>>
>>>>>> -	if (is_ixgbe_pmd(dev_info.driver_name) != 0)
>>>>>> +	if (is_ixgbe_pmd(dev->data->drv_name))
>>>>>>  		return -ENOTSUP;
>>>>>>
>>>>>
>>>>> The return value of is_ixgbe_pmd() is not boolean (actually I think
>>>>> it should be based on its name). If we omit the comparison with 0,
>>>>> the code looks weird. It looks like it'll return -ENOTSUP if the port's driver
>> is ixgbe PMD.
>>>>
>>>> Yes, it’s weird. But what makes it weird is not the missing comparison but
>> the function name.
>>>> Better changing it to ixgbe_pmd_check. How about it?
>>>>
>>>
>>> Yeah, I also prefer to change the helper function itself. But I'm not
>>> good at the naming. I'd like to hear others' opinion. :-)
>>
>> Agree that it looks wrong without 0 comparison.
>>
>> Helper function is checking if the given port is an ixgbe port or not,
>> unfortunately you need to this for PMD specific APIs.
>> So What about is_device_supported(),
>>
>> I agree it is better if it returns bool, and I also think it is better if it gets the
>> rte_eth_dev as input parameter, validating port based on name is API internal
>> knowledge.
>>
>> Also instead of name comparison against fixed string, it can be eth_dev-
>>> driver->pci_drv.name against driver->name. This makes function more
> Thanks for your suggestion. But I don’t get your point here. 
> For a specific device, should not the eth_dev->driver->pci_drv.name and the driver->name be the same?

Yes they are same.

But there is a intention to unlink "eth_drv->pci_drv", to better support
non pci devices,

so instead of a PMD directly accessing name through this link, I believe
it is better to use rte_drier->name, which is more generic.

> 
> 
>> generic, and perhaps this helper function can be moved into ethdev layer,
>> later. For this function needs to get both eth_dev and rte_driver as argument.
>>
>>
>>>
>>> Best regards,
>>> Tiwei Bie
>>>
>