[PATCH v2 10/18] cxl/region: Factor out code to find a root decoder's region

[Robert Richter <rrichter@amd.com>]

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>
---
 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 c641c8922455..9ce0282c0042 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3256,6 +3256,19 @@ static int match_region_by_range(struct device *dev, const void *data)
 	return rc;
 }
 
+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);
+}
+
 /* Establish an empty region covering the given HPA range */
 static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd,
 					   struct cxl_endpoint_decoder *cxled)
@@ -3347,7 +3360,6 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd,
 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;
@@ -3363,13 +3375,9 @@ 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);
@@ -3394,7 +3402,7 @@ 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() */
 
 	return rc;
 }
-- 
2.39.5