[PATCH 2/2] cxl/region: Unregister auto-created region when assembly fails

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

When auto-created region assembly fails the region remains registered
but disabled. The region continues to reserve its memory resource,
preventing DAX from registering the memory.

Unregister the region on assembly failure to release the resource.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 drivers/cxl/core/region.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 183cb0b49d8b..f222aa9cbda7 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3714,6 +3714,8 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd,
 	return cxlr;
 }
 
+static void unregister_region(void *dev);
+
 static struct cxl_region *
 cxl_find_region_by_range(struct cxl_root_decoder *cxlrd, struct range *hpa)
 {
@@ -3754,7 +3756,17 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
 	if (rc)
 		return rc;
 
-	attach_target(cxlr, cxled, -1, TASK_UNINTERRUPTIBLE);
+	rc = attach_target(cxlr, cxled, -1, TASK_UNINTERRUPTIBLE);
+	if (rc) {
+		struct cxl_port *root_port = cxlrd_to_port(cxlrd);
+
+		/* Messages at the point of failure offer more detail */
+		dev_err(&cxlr->dev,
+			"assembly failed %d, unregistering region\n", rc);
+		devm_release_action(root_port->uport_dev, unregister_region,
+				    cxlr);
+		return rc;
+	}
 
 	scoped_guard(rwsem_read, &cxl_rwsem.region) {
 		p = &cxlr->params;
-- 
2.37.3