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

[Ferruh Yigit <ferruh.yigit@intel.com>]

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@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@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 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
>