[PATCH v2] cxl: Adjust extended linear cache failure emission in cxl_acpi

[PATCH v2] cxl: Adjust extended linear cache failure emission in cxl_acpi

[Dave Jiang]

The cxl_acpi module spams "Extended linear cache calculation failed"
when the hmat memory target is not found for a node. This is normal
when the memory target does not contain extended linear cache
attributes. Adjust cxl_acpi_set_cache_size() to just return 0 if error
is returned from hmat_get_extended_linear_cache_size(). That is the
only error returned from hmat_get_extended_linear_cache_size() as
-ENOENT.

Also remove the check for -EOPNOTSUPP in cxl_setup_extended_linear_cache()
since that errno is never returned by cxl_acpi_set_cache_size().

Suggeted-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

---
v2:
- Rename subject line to reflect new changes.
- Further analysis of the code and determined this is the correct
  change.
---
 drivers/cxl/acpi.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index d7a5539d07d4..cc4d7bf381d3 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -353,7 +353,7 @@ static int cxl_acpi_set_cache_size(struct cxl_root_decoder *cxlrd)
 
 	rc = hmat_get_extended_linear_cache_size(&res, nid, &cache_size);
 	if (rc)
-		return rc;
+		return 0;
 
 	/*
 	 * The cache range is expected to be within the CFMWS.
@@ -381,15 +381,13 @@ static void cxl_setup_extended_linear_cache(struct cxl_root_decoder *cxlrd)
 	if (!rc)
 		return;
 
-	if (rc != -EOPNOTSUPP) {
-		/*
-		 * Failing to support extended linear cache region resize does not
-		 * prevent the region from functioning. Only causes cxl list showing
-		 * incorrect region size.
-		 */
-		dev_warn(cxlrd->cxlsd.cxld.dev.parent,
-			 "Extended linear cache calculation failed rc:%d\n", rc);
-	}
+	/*
+	 * Failing to retrieve extended linear cache region resize does not
+	 * prevent the region from functioning. Only causes cxl list showing
+	 * incorrect region size.
+	 */
+	dev_warn(cxlrd->cxlsd.cxld.dev.parent,
+		 "Extended linear cache retrieval failed rc:%d\n", rc);
 
 	/* Ignoring return code */
 	cxlrd->cache_size = 0;

base-commit: 46037455cbb748c5e85071c95f2244e81986eb58
-- 
2.51.0

Re: [PATCH v2] cxl: Adjust extended linear cache failure emission in cxl_acpi

[Jonathan Cameron]

On Fri, 3 Oct 2025 11:55:09 -0700
Dave Jiang <dave.jiang@intel.com> wrote:

> The cxl_acpi module spams "Extended linear cache calculation failed"
> when the hmat memory target is not found for a node. This is normal
> when the memory target does not contain extended linear cache
> attributes. Adjust cxl_acpi_set_cache_size() to just return 0 if error
> is returned from hmat_get_extended_linear_cache_size(). That is the
> only error returned from hmat_get_extended_linear_cache_size() as
> -ENOENT.
> 
> Also remove the check for -EOPNOTSUPP in cxl_setup_extended_linear_cache()
> since that errno is never returned by cxl_acpi_set_cache_size().
> 
> Suggeted-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Minor thing below. Either way
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

> 
> ---
> v2:
> - Rename subject line to reflect new changes.
> - Further analysis of the code and determined this is the correct
>   change.
> ---
>  drivers/cxl/acpi.c | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> index d7a5539d07d4..cc4d7bf381d3 100644
> --- a/drivers/cxl/acpi.c
> +++ b/drivers/cxl/acpi.c
> @@ -353,7 +353,7 @@ static int cxl_acpi_set_cache_size(struct cxl_root_decoder *cxlrd)
>  
>  	rc = hmat_get_extended_linear_cache_size(&res, nid, &cache_size);
>  	if (rc)
> -		return rc;
> +		return 0;
>  
>  	/*
>  	 * The cache range is expected to be within the CFMWS.
> @@ -381,15 +381,13 @@ static void cxl_setup_extended_linear_cache(struct cxl_root_decoder *cxlrd)
>  	if (!rc)
>  		return;
I'd prefer a logic flip so the error is out of line.

	if (rc) {
		/*
		 * Failing to support extended linear cache region resize does not
		 * prevent the region from functioning. Only causes cxl list showing
		 * incorrect region size.
		 */
		dev_warn(cxlrd->cxlsd.cxld.dev.parent,
			 "Extended linear cache calculation failed rc:%d\n", rc);
 		cxlrd->cache_size = 0;
	}
}
>  
> -	if (rc != -EOPNOTSUPP) {
> -		/*
> -		 * Failing to support extended linear cache region resize does not
> -		 * prevent the region from functioning. Only causes cxl list showing
> -		 * incorrect region size.
> -		 */
> -		dev_warn(cxlrd->cxlsd.cxld.dev.parent,
> -			 "Extended linear cache calculation failed rc:%d\n", rc);
> -	}
> +	/*
> +	 * Failing to retrieve extended linear cache region resize does not
> +	 * prevent the region from functioning. Only causes cxl list showing
> +	 * incorrect region size.
> +	 */
> +	dev_warn(cxlrd->cxlsd.cxld.dev.parent,
> +		 "Extended linear cache retrieval failed rc:%d\n", rc);
>  
>  	/* Ignoring return code */
>  	cxlrd->cache_size = 0;
> 
> base-commit: 46037455cbb748c5e85071c95f2244e81986eb58

Re: [PATCH v2] cxl: Adjust extended linear cache failure emission in cxl_acpi

[Alison Schofield]

On Fri, Oct 03, 2025 at 11:55:09AM -0700, Dave Jiang wrote:
> The cxl_acpi module spams "Extended linear cache calculation failed"
> when the hmat memory target is not found for a node. This is normal
> when the memory target does not contain extended linear cache
> attributes. Adjust cxl_acpi_set_cache_size() to just return 0 if error
> is returned from hmat_get_extended_linear_cache_size(). That is the
> only error returned from hmat_get_extended_linear_cache_size() as
> -ENOENT.
> 
> Also remove the check for -EOPNOTSUPP in cxl_setup_extended_linear_cache()
> since that errno is never returned by cxl_acpi_set_cache_size().


WFM in cxl-test module. Messages like these are gone:
cxl root0: Extended linear cache calculation failed rc:-2

I'll second Jonathan's logic flip suggestion, and with that,
Reviewed-by: Alison Schofield <alison.schofield@intel.com>

> 
> Suggeted-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> 

Re: [PATCH v2] cxl: Adjust extended linear cache failure emission in cxl_acpi

[Dave Jiang]

On 10/3/25 11:55 AM, Dave Jiang wrote:
> The cxl_acpi module spams "Extended linear cache calculation failed"
> when the hmat memory target is not found for a node. This is normal
> when the memory target does not contain extended linear cache
> attributes. Adjust cxl_acpi_set_cache_size() to just return 0 if error
> is returned from hmat_get_extended_linear_cache_size(). That is the
> only error returned from hmat_get_extended_linear_cache_size() as
> -ENOENT.
> 
> Also remove the check for -EOPNOTSUPP in cxl_setup_extended_linear_cache()
> since that errno is never returned by cxl_acpi_set_cache_size().
> 
> Suggeted-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Applied to cxl/next
f0c5d3bc2830f04a72087f45d15807943eabfa10

> 
> ---
> v2:
> - Rename subject line to reflect new changes.
> - Further analysis of the code and determined this is the correct
>   change.
> ---
>  drivers/cxl/acpi.c | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> index d7a5539d07d4..cc4d7bf381d3 100644
> --- a/drivers/cxl/acpi.c
> +++ b/drivers/cxl/acpi.c
> @@ -353,7 +353,7 @@ static int cxl_acpi_set_cache_size(struct cxl_root_decoder *cxlrd)
>  
>  	rc = hmat_get_extended_linear_cache_size(&res, nid, &cache_size);
>  	if (rc)
> -		return rc;
> +		return 0;
>  
>  	/*
>  	 * The cache range is expected to be within the CFMWS.
> @@ -381,15 +381,13 @@ static void cxl_setup_extended_linear_cache(struct cxl_root_decoder *cxlrd)
>  	if (!rc)
>  		return;
>  
> -	if (rc != -EOPNOTSUPP) {
> -		/*
> -		 * Failing to support extended linear cache region resize does not
> -		 * prevent the region from functioning. Only causes cxl list showing
> -		 * incorrect region size.
> -		 */
> -		dev_warn(cxlrd->cxlsd.cxld.dev.parent,
> -			 "Extended linear cache calculation failed rc:%d\n", rc);
> -	}
> +	/*
> +	 * Failing to retrieve extended linear cache region resize does not
> +	 * prevent the region from functioning. Only causes cxl list showing
> +	 * incorrect region size.
> +	 */
> +	dev_warn(cxlrd->cxlsd.cxld.dev.parent,
> +		 "Extended linear cache retrieval failed rc:%d\n", rc);
>  
>  	/* Ignoring return code */
>  	cxlrd->cache_size = 0;
> 
> base-commit: 46037455cbb748c5e85071c95f2244e81986eb58