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

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

On 7/12/2019 4:10 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;

Am I missing something?