RE: [PATCH] net/mlx5: fix linux stats gathering function

[Matan Azrad <matan@nvidia.com>]

From: Geoffrey Le Gourriérec
> This patch encompasses a few fixes carried by a previous patch that aimed to
> support bonding device stats counting.
> 
> - If mlx5_os_read_dev_stat fails, it returns 1 instead of a
>   negative value, causing mlx5_xstats_get to return an invalid
>   number of counters. Since this error is not blocking, do not
>   mess ret value with mlx5_os_read_dev_stat returned value.
> 
>   This allows avoiding the very annoying log:
>   "n_xstats != n_xstats_names => skipping"
> 
> - Invert the check for mlx5_os_read_dev_stat(), currently leading
>   us to store the result if the function failed, and use a
>   backup value if it succeeded, which is the opposite of what we
>   actually want. Revert to the original (correct) test.
> 
> - Add missing test on _mlx5_os_read_dev_counters() to prevent
>   using trash stats values.
> 
> Fixes: 7ed15acdcd69 ("net/mlx5: improve xstats of bonding port")
> Signed-off-by: Didier Pallard <didier.pallard@6wind.com>
> Signed-off-by: Geoffrey Le Gourriérec
> <geoffrey.le_gourrierec@6wind.com>
Acked-by: Matan Azrad <matan@nvidia.com>