Re: [PATCH net-next 09/14] net/mlx5: Remove obsolete 32-bit DMA mask fallback

[Tariq Toukan <tariqt@nvidia.com>]

On 03/09/2026 11:43, Ruizhe Zhou wrote:
> The DMA API guarantees support for masks of 32 bits or wider and
> explicitly identifies retrying a 32-bit mask after a 64-bit request as
> incorrect:
> https://docs.kernel.org/core-api/dma-api-howto.html#dma-addressing-capabilities
> 
> Remove the obsolete fallback while retaining the error check so that a
> genuine DMA setup failure is still reported and aborts initialization.
> 
> Signed-off-by: Ruizhe Zhou <zhouruizhe@resnics.com>
> ---
>   drivers/net/ethernet/mellanox/mlx5/core/main.c | 8 ++------
>   1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> index 5f28d906c35b..3a3b0ec4aad1 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> @@ -184,12 +184,8 @@ static int set_dma_caps(struct pci_dev *pdev)
>   
>   	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
>   	if (err) {
> -		dev_warn(&pdev->dev, "Warning: couldn't set 64-bit PCI DMA mask\n");
> -		err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> -		if (err) {
> -			dev_err(&pdev->dev, "Can't set PCI DMA mask, aborting\n");
> -			return err;
> -		}
> +		dev_err(&pdev->dev, "Can't set PCI DMA mask, aborting\n");
> +		return err;
>   	}
>   
>   	dma_set_max_seg_size(&pdev->dev, 2u * 1024 * 1024 * 1024);

Reviewed-by: Tariq Toukan <tariqt@nvidia.com>