Re: [dpdk-dev] [PATCH] net/af_xdp: fix xdp_get_channels_info return value

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

On 7/12/2019 4:48 PM, Stephen Hemminger wrote:
> On Fri, 12 Jul 2019 16:35:55 +0100
> Ferruh Yigit <ferruh.yigit@intel.com> wrote:
> 
>> On 7/12/2019 4:10 PM, Stephen Hemminger wrote:
>>> On Fri, 12 Jul 2019 09:55:46 +0200
>>> Július Milan <jmilan.dev@gmail.com> wrote:
>>>   
>>>> Procedure xdp_get_channels_info was returning error code -1 in case of
>>>> ioctl command SIOCETHTOOL was not supported. This patch sets return
>>>> value back to 0 as it is valid case.
>>>>
>>>> Fixes: 339b88c6a9 ("net/af_xdp: support multi-queue")
>>>>
>>>> Signed-off-by: Július Milan <jmilan.dev@gmail.com>
>>>> ---
>>>>  drivers/net/af_xdp/rte_eth_af_xdp.c | 10 +++++++---
>>>>  1 file changed, 7 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c b/drivers/net/af_xdp/rte_eth_af_xdp.c
>>>> index ff8e90589..33352e10a 100644
>>>> --- a/drivers/net/af_xdp/rte_eth_af_xdp.c
>>>> +++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
>>>> @@ -852,9 +852,13 @@ xdp_get_channels_info(const char *if_name, int *max_queues,
>>>>  	ifr.ifr_data = (void *)&channels;
>>>>  	strncpy(ifr.ifr_name, if_name, IFNAMSIZ);
>>>>  	ret = ioctl(fd, SIOCETHTOOL, &ifr);
>>>> -	if (ret && errno != EOPNOTSUPP) {
>>>> -		ret = -errno;
>>>> -		goto out;
>>>> +	if (ret) {
>>>> +		if (errno == EOPNOTSUPP) {
>>>> +			ret = 0;
>>>> +		} else {
>>>> +			ret = -errno;
>>>> +			goto out;
>>>> +		}
>>>>  	}
>>>>  
>>>>  	if (channels.max_combined == 0 || errno == EOPNOTSUPP) {  
>>>
>>> Still wrong, it doesn't set max_queues/combined_queues if errno == EOPNOTSUPP
>>>   
>>
>> Looks like code only fixes the return value, which was 'ret' before, now  '0',
>> the remaining logic should be same.
>>
>> as far as I can see, if errno == EOPNOTSUPP, it sets
>>   *max_queues = 1;
>>   *combined_queues = channels.combined_count;
> 
> OK, it does return correctly, just the hard way to do it.
> Keep it for now, I will do a cleanup pass over AF_XDP later.
> Lots  of things could be done simpler
> 

ok