[PATCH v3 06/10] net/axgbe: adjust retval when xstats is null of get xstats

[Andrew Rybchenko]

On 5/5/22 11:02, Chengwen Feng wrote:
> Many user (e.g. telemetry) invokes rte_eth_xstats_get(port_id, NULL, 0)
> to retrieve the required number of elements, but currently axgbe PMD
> returns zero when xstats is NULL.
> 
> This patch adjusts that the return value was the required number of
> elements when stats is NULL.
> 
> Fixes: 9d1ef6b2e731 ("net/axgbe: add xstats")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Chengwen Feng <fengchengwen at huawei.com>
> ---
>   drivers/net/axgbe/axgbe_ethdev.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/axgbe/axgbe_ethdev.c b/drivers/net/axgbe/axgbe_ethdev.c
> index 951da5cc26..f6a3a52430 100644
> --- a/drivers/net/axgbe/axgbe_ethdev.c
> +++ b/drivers/net/axgbe/axgbe_ethdev.c
> @@ -1014,7 +1014,7 @@ axgbe_dev_xstats_get(struct rte_eth_dev *dev, struct rte_eth_xstat *stats,
>   	unsigned int i;
>   
>   	if (!stats)

I think the right condition is: n < AXGBE_XSTATS_COUNT
Otherwise the function break contract to return required
number of xstats if space is insufficient.

> -		return 0;
> +		return AXGBE_XSTATS_COUNT;
>   
>   	axgbe_read_mmc_stats(pdata);
>