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

[Stephen Hemminger]

On Fri, 12 Jul 2019 09:40:37 +0200
Július Milan <jmilan....@gmail.com> wrote:

> 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;
> +        }
>      }


Why not do close first and avoid the goto?
With your code, max_queues and combined_queues would never get set.


        ret = ioctl(fd, SIOCETHTOOL, &ifr);
        close(fd);
        if (ret < 0 && errno != EOPNOTSUPP)
                return -errno;

        if (errno == EOPNOTSUPP || channels.max_combined == 0) {
...