Re: [PATCH v14 16/22] cxl/region: factor out interleave ways setup

[Alison Schofield <alison.schofield@intel.com>]

On Thu, Apr 17, 2025 at 10:29:19PM +0100, alejandro.lucero-palau@amd.com wrote:
> From: Alejandro Lucero <alucerop@amd.com>
> 
> In preparation for kernel driven region creation, factor out a common

Please define "kernel driven region creation".

Also, please keep repeating that these changes are introduced for Type 2
support and note whether there is any functional change to existing region
creation path.


> helper from the user-sysfs region setup for interleave ways.
> 
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> Reviewed-by: Zhi Wang <zhiw@nvidia.com>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
> ---
>  drivers/cxl/core/region.c | 46 +++++++++++++++++++++++----------------
>  1 file changed, 27 insertions(+), 19 deletions(-)


> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 6371284283b0..095e52237516 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -464,22 +464,14 @@ static ssize_t interleave_ways_show(struct device *dev,
>  
>  static const struct attribute_group *get_cxl_region_target_group(void);
>  
> -static ssize_t interleave_ways_store(struct device *dev,
> -				     struct device_attribute *attr,
> -				     const char *buf, size_t len)
> +static int set_interleave_ways(struct cxl_region *cxlr, int val)
>  {
> -	struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev->parent);
> +	struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(cxlr->dev.parent);
>  	struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
> -	struct cxl_region *cxlr = to_cxl_region(dev);
>  	struct cxl_region_params *p = &cxlr->params;
> -	unsigned int val, save;
> -	int rc;
> +	int save, rc;
>  	u8 iw;
>  
> -	rc = kstrtouint(buf, 0, &val);
> -	if (rc)
> -		return rc;
> -
>  	rc = ways_to_eiw(val, &iw);
>  	if (rc)
>  		return rc;
> @@ -494,20 +486,36 @@ static ssize_t interleave_ways_store(struct device *dev,
>  		return -EINVAL;
>  	}
>  
> -	rc = down_write_killable(&cxl_region_rwsem);
> -	if (rc)
> -		return rc;
> -	if (p->state >= CXL_CONFIG_INTERLEAVE_ACTIVE) {
> -		rc = -EBUSY;
> -		goto out;
> -	}
> +	lockdep_assert_held_write(&cxl_region_rwsem);
> +	if (p->state >= CXL_CONFIG_INTERLEAVE_ACTIVE)
> +		return -EBUSY;
>  
>  	save = p->interleave_ways;
>  	p->interleave_ways = val;
>  	rc = sysfs_update_group(&cxlr->dev.kobj, get_cxl_region_target_group());
>  	if (rc)
>  		p->interleave_ways = save;
> -out:
> +
> +	return rc;
> +}
> +
> +static ssize_t interleave_ways_store(struct device *dev,
> +				     struct device_attribute *attr,
> +				     const char *buf, size_t len)
> +{
> +	struct cxl_region *cxlr = to_cxl_region(dev);
> +	unsigned int val;
> +	int rc;
> +
> +	rc = kstrtouint(buf, 0, &val);
> +	if (rc)
> +		return rc;
> +
> +	rc = down_write_killable(&cxl_region_rwsem);
> +	if (rc)
> +		return rc;
> +
> +	rc = set_interleave_ways(cxlr, val);
>  	up_write(&cxl_region_rwsem);
>  	if (rc)
>  		return rc;
> -- 
> 2.34.1
> 
>