Re: [PATCH v4 09/14] cxl/region: Factor out code to find a root decoder's region

[Dan Williams <dan.j.williams@intel.com>]

Robert Richter wrote:
> In function cxl_add_to_region() there is code to determine a root
> decoder's region. Factor that code out. This is in preparation to
> further rework and simplify function cxl_add_to_region().
> 
> No functional changes.
> 
> Signed-off-by: Robert Richter <rrichter@amd.com>
> Reviewed-by: Gregory Price <gourry@gourry.net>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> Tested-by: Gregory Price <gourry@gourry.net>
> ---
>  drivers/cxl/core/region.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 7d9d9b8f9eea..70ff4c94fb7a 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3416,10 +3416,22 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd,
>  	return cxlr;
>  }
>  
> +static struct cxl_region *
> +cxl_find_region_by_range(struct cxl_root_decoder *cxlrd, struct range *hpa)
> +{
> +	struct device *region_dev;
> +
> +	region_dev = device_find_child(&cxlrd->cxlsd.cxld.dev, hpa,
> +				       match_region_by_range);
> +	if (!region_dev)
> +		return NULL;
> +
> +	return to_cxl_region(region_dev);
> +}
> +
>  int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
>  {
>  	struct range *hpa = &cxled->cxld.hpa_range;
> -	struct device *region_dev;
>  	struct cxl_root_decoder *cxlrd;
>  	struct cxl_region_params *p;
>  	struct cxl_region *cxlr;
> @@ -3435,13 +3447,9 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
>  	 * one does the construction and the others add to that.
>  	 */
>  	mutex_lock(&cxlrd->range_lock);
> -	region_dev = device_find_child(&cxlrd->cxlsd.cxld.dev, hpa,
> -				       match_region_by_range);
> -	if (!region_dev) {
> +	cxlr = cxl_find_region_by_range(cxlrd, hpa);
> +	if (!cxlr)
>  		cxlr = construct_region(cxlrd, cxled);
> -		region_dev = &cxlr->dev;
> -	} else
> -		cxlr = to_cxl_region(region_dev);
>  	mutex_unlock(&cxlrd->range_lock);
>  
>  	rc = PTR_ERR_OR_ZERO(cxlr);
> @@ -3466,7 +3474,7 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
>  				p->res);
>  	}
>  
> -	put_device(region_dev);
> +	put_device(&cxlr->dev);			/* cxl_find_region_by_range() */

I would not mind a DEFINE_FREE(put_cxl_region, ...) to automate this cleanup,
but other than that:

Reviewed-by: Dan Williams <dan.j.williams@intel.com>