Subject: Re: [PATCH v7 23/28] sfc: create cxl region

From: Simon Horman <[email-masked]>
Date: Thu, 12 Dec 2024 18:29:33 +0000

On Mon, Dec 09, 2024 at 06:54:24PM +0000, [email-masked] wrote:
> From: Alejandro Lucero <[email-masked]>
> 
> Use cxl api for creating a region using the endpoint decoder related to
> a DPA range.
> 
> Signed-off-by: Alejandro Lucero <[email-masked]>
> Reviewed-by: Martin Habets <[email-masked]>
> ---
>  drivers/net/ethernet/sfc/efx_cxl.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
> index 09827bb9e861..9b34795f7853 100644
> --- a/drivers/net/ethernet/sfc/efx_cxl.c
> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
> @@ -128,10 +128,19 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
>  		goto err3;
>  	}
>  
> +	cxl->efx_region = cxl_create_region(cxl->cxlrd, cxl->cxled);
> +	if (!cxl->efx_region) {
> +		pci_err(pci_dev, "CXL accel create region failed");
> +		rc = PTR_ERR(cxl->efx_region);
> +		goto err_region;

Hi Alejandro,

This is similar to my feedback on patch 18/28.

Looking over the implementation of cxl_create_region it seems
that it returns either a valid pointer or an error pointer, but
not NULL. If so, I think the correct condition would be
(completely untested):

	if (IS_ERR(cxl->efx_region)

But if cxl->efx_region can be NULL then rc, the return value of this
function, will be set to zero. Which doesn't seem correct given
the error message above.

> +	}
> +
>  	probe_data->cxl = cxl;
>  
>  	return 0;
>  
> +err_region:
> +	cxl_dpa_free(cxl->cxled);
>  err3:
>  	cxl_release_resource(cxl->cxlds, CXL_RES_RAM);
>  err2:
> @@ -144,6 +153,7 @@ 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_accel_region_detach(probe_data->cxl->cxled);
>  		cxl_dpa_free(probe_data->cxl->cxled);
>  		cxl_release_resource(probe_data->cxl->cxlds, CXL_RES_RAM);
>  		kfree(probe_data->cxl->cxlds);
> -- 
> 2.17.1
> 
>