Subject: Re: [PATCH v7 18/28] sfc: get endpoint decoder

From: Simon Horman <[email-masked]>
Date: Thu, 12 Dec 2024 18:21:10 +0000

On Mon, Dec 09, 2024 at 06:54:19PM +0000, [email-masked] wrote:
> From: Alejandro Lucero <[email-masked]>
> 
> Use cxl api for getting DPA (Device Physical Address) to use through an
> endpoint decoder.
> 
> Signed-off-by: Alejandro Lucero <[email-masked]>
> Reviewed-by: Martin Habets <[email-masked]>
> ---
>  drivers/net/ethernet/sfc/efx_cxl.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
> index f2dc025c9fbb..09827bb9e861 100644
> --- a/drivers/net/ethernet/sfc/efx_cxl.c
> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
> @@ -120,6 +120,14 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
>  		goto err3;
>  	}
>  
> +	cxl->cxled = cxl_request_dpa(cxl->cxlmd, true, EFX_CTPIO_BUFFER_SIZE,
> +				     EFX_CTPIO_BUFFER_SIZE);
> +	if (IS_ERR_OR_NULL(cxl->cxled)) {

Hi Alejandro,

The Kernel doc for cxl_request_dpa says that it returns either
a valid pointer or an error pointer. So perhaps IS_ERR() is
sufficient here.

> +		pci_err(pci_dev, "CXL accel request DPA failed");
> +		rc = PTR_ERR(cxl->cxlrd);

Otherwise, if cxl->cxlrd is NULL here, then rc, the return value for
this function, will be 0 here. Which doesn't seem to align with the
error message on the line above.

Flagged by Smatch.

> +		goto err3;
> +	}
> +
>  	probe_data->cxl = cxl;
>  
>  	return 0;
> @@ -136,6 +144,7 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
>  void efx_cxl_exit(struct efx_probe_data *probe_data)
>  {
>  	if (probe_data->cxl) {
> +		cxl_dpa_free(probe_data->cxl->cxled);
>  		cxl_release_resource(probe_data->cxl->cxlds, CXL_RES_RAM);
>  		kfree(probe_data->cxl->cxlds);
>  		kfree(probe_data->cxl);
> -- 
> 2.17.1
> 
>