[PATCH v3 10/18] cxl/region: Factor out code to find a root decoder's region

Robert Richter
2025-02-11T09:54:57Z

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>
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 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