cxl: Convert find_cxl_root() to return a 'struct cxl_root *'

Commit 790815902ec6 ("cxl: Add support for _DSM Function for retrieving QTG ID")
introduced 'struct cxl_root', however all usages have been worked
indirectly through cxl_port. Refactor code such as find_cxl_root()
function to use 'struct cxl_root' directly.

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/170449246044.3779673.13035770941393418591.stgit@djiang5-mobl3
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

3 files changed, 16 insertions, 11 deletions

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index cd84d87f597a..0df5379cf02f 100644
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -162,7 +162,6 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
 					struct xarray *dsmas_xa)
 {
 	struct access_coordinate c;
-	struct cxl_port *root_port;
 	struct cxl_root *cxl_root;
 	struct dsmas_entry *dent;
 	int valid_entries = 0;
@@ -175,8 +174,7 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
 		return rc;
 	}
 
-	root_port = find_cxl_root(port);
-	cxl_root = to_cxl_root(root_port);
+	cxl_root = find_cxl_root(port);
 	if (!cxl_root->ops || !cxl_root->ops->qos_class)
 		return -EOPNOTSUPP;
 
@@ -193,7 +191,8 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
 						    dent->coord.write_bandwidth);
 
 		dent->entries = 1;
-		rc = cxl_root->ops->qos_class(root_port, &dent->coord, 1, &qos_class);
+		rc = cxl_root->ops->qos_class(cxl_root, &dent->coord, 1,
+					      &qos_class);
 		if (rc != 1)
 			continue;
 
@@ -349,15 +348,19 @@ static int cxl_qos_class_verify(struct cxl_memdev *cxlmd)
 {
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
-	struct cxl_port *root_port __free(put_device) = NULL;
 	LIST_HEAD(__discard);
 	struct list_head *discard __free(dpa_perf) = &__discard;
+	struct cxl_port *root_port;
 	int rc;
 
-	root_port = find_cxl_root(cxlmd->endpoint);
-	if (!root_port)
+	struct cxl_root *cxl_root __free(put_cxl_root) =
+		find_cxl_root(cxlmd->endpoint);
+
+	if (!cxl_root)
 		return -ENODEV;
 
+	root_port = &cxl_root->port;
+
 	/* Check that the QTG IDs are all sane between end device and root decoders */
 	cxl_qos_match(root_port, &mds->ram_perf_list, discard);
 	cxl_qos_match(root_port, &mds->pmem_perf_list, discard);
diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c
index fc94f5240327..da92a901b9e8 100644
--- a/drivers/cxl/core/pmem.c
+++ b/drivers/cxl/core/pmem.c
@@ -64,12 +64,14 @@ static int match_nvdimm_bridge(struct device *dev, void *data)
 
 struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_memdev *cxlmd)
 {
-	struct cxl_port *port = find_cxl_root(cxlmd->endpoint);
+	struct cxl_root *cxl_root = find_cxl_root(cxlmd->endpoint);
+	struct cxl_port *port;
 	struct device *dev;
 
-	if (!port)
+	if (!cxl_root)
 		return NULL;
 
+	port = &cxl_root->port;
 	dev = device_find_child(&port->dev, NULL, match_nvdimm_bridge);
 	put_device(&port->dev);
 
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 64f30d5fe1f6..63a4e3c2baed 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -972,7 +972,7 @@ static bool dev_is_cxl_root_child(struct device *dev)
 	return false;
 }
 
-struct cxl_port *find_cxl_root(struct cxl_port *port)
+struct cxl_root *find_cxl_root(struct cxl_port *port)
 {
 	struct cxl_port *iter = port;
 
@@ -982,7 +982,7 @@ struct cxl_port *find_cxl_root(struct cxl_port *port)
 	if (!iter)
 		return NULL;
 	get_device(&iter->dev);
-	return iter;
+	return to_cxl_root(iter);
 }
 EXPORT_SYMBOL_NS_GPL(find_cxl_root, CXL);