linux-kernel - [PATCH v1 05/29] cxl/region: Move find_cxl_root() to cxl_add_to

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Message-ID: <20250107141015.3367194-6-rrichter@amd.com>
Date: Tue, 7 Jan 2025 15:09:51 +0100
From: Robert Richter <rrichter@....com>
To: Alison Schofield <alison.schofield@...el.com>, Vishal Verma
	<vishal.l.verma@...el.com>, Ira Weiny <ira.weiny@...el.com>, Dan Williams
	<dan.j.williams@...el.com>, Jonathan Cameron <jonathan.cameron@...wei.com>,
	Dave Jiang <dave.jiang@...el.com>, Davidlohr Bueso <dave@...olabs.net>
CC: <linux-cxl@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Gregory Price
	<gourry@...rry.net>, "Fabio M. De Francesco"
	<fabio.m.de.francesco@...ux.intel.com>, Terry Bowman <terry.bowman@....com>,
	Robert Richter <rrichter@....com>
Subject: [PATCH v1 05/29] cxl/region: Move find_cxl_root() to cxl_add_to_region()

When adding an endpoint to a region, the root port is determined
first. Move this directly into cxl_add_to_region(). This is in
preparation of the initialization of endpoints that iterates the port
hierarchy from the endpoint up to the root port.

As a side-effect the root argument is removed from the argument lists
of cxl_add_to_region() and related functions. Now, the endpoint is the
only parameter to add a region. This simplifies the function
interface.

Signed-off-by: Robert Richter <rrichter@....com>
---
 drivers/cxl/core/region.c |  6 ++++--
 drivers/cxl/cxl.h         |  6 ++----
 drivers/cxl/port.c        | 15 +++------------
 3 files changed, 9 insertions(+), 18 deletions(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 9b3efa841c8f..752440a5c162 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3307,9 +3307,11 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd,
 	return ERR_PTR(rc);
 }
 
-int cxl_add_to_region(struct cxl_port *root, struct cxl_endpoint_decoder *cxled)
+int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
 {
 	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
+	struct cxl_port *port = cxled_to_port(cxled);
+	struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);
 	struct range *hpa = &cxled->cxld.hpa_range;
 	struct cxl_decoder *cxld = &cxled->cxld;
 	struct device *cxlrd_dev, *region_dev;
@@ -3319,7 +3321,7 @@ int cxl_add_to_region(struct cxl_port *root, struct cxl_endpoint_decoder *cxled)
 	bool attach = false;
 	int rc;
 
-	cxlrd_dev = device_find_child(&root->dev, &cxld->hpa_range,
+	cxlrd_dev = device_find_child(&cxl_root->port.dev, &cxld->hpa_range,
 				      match_root_decoder_by_range);
 	if (!cxlrd_dev) {
 		dev_err(cxlmd->dev.parent,
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index fdac3ddb8635..5c1a55181e0f 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -872,8 +872,7 @@ struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_port *port);
 #ifdef CONFIG_CXL_REGION
 bool is_cxl_pmem_region(struct device *dev);
 struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev);
-int cxl_add_to_region(struct cxl_port *root,
-		      struct cxl_endpoint_decoder *cxled);
+int cxl_add_to_region(struct cxl_endpoint_decoder *cxled);
 struct cxl_dax_region *to_cxl_dax_region(struct device *dev);
 #else
 static inline bool is_cxl_pmem_region(struct device *dev)
@@ -884,8 +883,7 @@ static inline struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
 {
 	return NULL;
 }
-static inline int cxl_add_to_region(struct cxl_port *root,
-				    struct cxl_endpoint_decoder *cxled)
+static inline int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
 {
 	return 0;
 }
diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
index d2bfd1ff5492..74587a403e3d 100644
--- a/drivers/cxl/port.c
+++ b/drivers/cxl/port.c
@@ -30,7 +30,7 @@ static void schedule_detach(void *cxlmd)
 	schedule_cxl_memdev_detach(cxlmd);
 }
 
-static int discover_region(struct device *dev, void *root)
+static int discover_region(struct device *dev, void *unused)
 {
 	struct cxl_endpoint_decoder *cxled;
 	int rc;
@@ -49,7 +49,7 @@ static int discover_region(struct device *dev, void *root)
 	 * Region enumeration is opportunistic, if this add-event fails,
 	 * continue to the next endpoint decoder.
 	 */
-	rc = cxl_add_to_region(root, cxled);
+	rc = cxl_add_to_region(cxled);
 	if (rc)
 		dev_dbg(dev, "failed to add to region: %#llx-%#llx\n",
 			cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end);
@@ -95,7 +95,6 @@ static int cxl_endpoint_port_probe(struct cxl_port *port)
 	struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport_dev);
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_hdm *cxlhdm;
-	struct cxl_port *root;
 	int rc;
 
 	rc = cxl_dvsec_rr_decode(cxlds, &info);
@@ -126,19 +125,11 @@ static int cxl_endpoint_port_probe(struct cxl_port *port)
 	if (rc)
 		return rc;
 
-	/*
-	 * This can't fail in practice as CXL root exit unregisters all
-	 * descendant ports and that in turn synchronizes with cxl_port_probe()
-	 */
-	struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);
-
-	root = &cxl_root->port;
-
 	/*
 	 * Now that all endpoint decoders are successfully enumerated, try to
 	 * assemble regions from committed decoders
 	 */
-	device_for_each_child(&port->dev, root, discover_region);
+	device_for_each_child(&port->dev, NULL, discover_region);
 
 	return 0;
 }
-- 
2.39.5