Re: [PATCH] net/mlx5: fix inconsistent link status query

["Nélio Laranjeiro" <nelio.laranjeiro@6wind.com>]

On Tue, Jul 25, 2017 at 01:37:39PM +0530, Gowrishankar wrote:
> From: Gowrishankar Muthukrishnan <gowrishankar.m@linux.vnet.ibm.com>
> 
> ETHTOOL_GLINKSETTINGS ioctl call in mlx5 pmd returns inconsistent
> link status due to which any application relying on it would not
> function correctly.
> 
> Fixes: 188408719888 ("net/mlx5: fix support for newer link speeds")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Gowrishankar Muthukrishnan <gowrishankar.m@linux.vnet.ibm.com>
> ---
> v3:
>  - stick with C standard for uint32_t
>  
>  drivers/net/mlx5/mlx5_ethdev.c | 28 ++++++++++++++++++++--------
>  1 file changed, 20 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
> index b70b7b9..01f881e 100644
> --- a/drivers/net/mlx5/mlx5_ethdev.c
> +++ b/drivers/net/mlx5/mlx5_ethdev.c
> @@ -119,6 +119,7 @@ struct ethtool_link_settings {
>  #define ETHTOOL_LINK_MODE_100000baseCR4_Full_BIT 38
>  #define ETHTOOL_LINK_MODE_100000baseLR4_ER4_Full_BIT 39
>  #endif
> +#define ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32	(SCHAR_MAX)

As I have another comment about compilation stuff, I would also ask to
remove those extra spaces.

>  /**
>   * Return private structure associated with an Ethernet device.
> @@ -807,9 +808,12 @@ struct priv *
>  mlx5_link_update_unlocked_gs(struct rte_eth_dev *dev, int wait_to_complete)
>  {
>  	struct priv *priv = mlx5_get_priv(dev);
> -	struct ethtool_link_settings edata = {
> -		.cmd = ETHTOOL_GLINKSETTINGS,
> -	};
> +	struct {

Misses the __extension__ before struct here.
struct ethtool_link_settings is finishing with a flexible array (e.g.
[0])  which avoids it to be included in another structure as it breaks
the standard.  

> +		struct ethtool_link_settings edata;
> +		uint32_t link_mode_data[3 *
> +					ETHTOOL_LINK_MODE_MASK_MAX_KERNEL_NU32];
> +	} ecmd;

Please add this __extension__ and it will be good ;)

Thanks,

-- 
Nélio Laranjeiro
6WIND