Subject: Re: [PATCH v1 14/14] net/mlx4: Use irq_update_affinity_hint

From: Leon Romanovsky <[email-masked]>
Date: Mon, 21 Jun 2021 11:01:06 +0300

On Thu, Jun 17, 2021 at 02:22:42PM -0400, Nitesh Narayan Lal wrote:
> The driver uses irq_set_affinity_hint() to update the affinity_hint mask
> that is consumed by the userspace to distribute the interrupts. However,
> under the hood irq_set_affinity_hint() also applies the provided cpumask
> (if not NULL) as the affinity for the given interrupt which is an
> undocumented side effect.
> 
> To remove this side effect irq_set_affinity_hint() has been marked
> as deprecated and new interfaces have been introduced. Hence, replace the
> irq_set_affinity_hint() with the new interface irq_update_affinity_hint()
> that only updates the affinity_hint pointer.
> 
> Signed-off-by: Nitesh Narayan Lal <[email-masked]>
> ---
>  drivers/net/ethernet/mellanox/mlx4/eq.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/eq.c b/drivers/net/ethernet/mellanox/mlx4/eq.c
> index 9e48509ed3b2..f549d697ca95 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/eq.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/eq.c
> @@ -244,9 +244,9 @@ static void mlx4_set_eq_affinity_hint(struct mlx4_priv *priv, int vec)
>  	    cpumask_empty(eq->affinity_mask))
>  		return;
>  
> -	hint_err = irq_set_affinity_hint(eq->irq, eq->affinity_mask);
> +	hint_err = irq_update_affinity_hint(eq->irq, eq->affinity_mask);
>  	if (hint_err)
> -		mlx4_warn(dev, "irq_set_affinity_hint failed, err %d\n", hint_err);
> +		mlx4_warn(dev, "irq_update_affinity_hint failed, err %d\n", hint_err);
>  }
>  #endif
>  
> @@ -1124,7 +1124,7 @@ static void mlx4_free_irqs(struct mlx4_dev *dev)
>  		if (eq_table->eq[i].have_irq) {
>  			free_cpumask_var(eq_table->eq[i].affinity_mask);
>  #if defined(CONFIG_SMP)
> -			irq_set_affinity_hint(eq_table->eq[i].irq, NULL);
> +			irq_update_affinity_hint(eq_table->eq[i].irq, NULL);
>  #endif

This #if/endif can be deleted.

Thanks,
Reviewed-by: Leon Romanovsky <[email-masked]>