linux-kernel - [PATCH v5 1/7] cxl/acpi: Refactor cxl_acpi_probe() to always schedule fallback DAX registration

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Message-ID: <20250715180407.47426-2-Smita.KoralahalliChannabasappa@amd.com>
Date: Tue, 15 Jul 2025 18:04:01 +0000
From: Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
To: <linux-cxl@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<nvdimm@...ts.linux.dev>, <linux-fsdevel@...r.kernel.org>,
	<linux-pm@...r.kernel.org>
CC: Davidlohr Bueso <dave@...olabs.net>, Jonathan Cameron
	<jonathan.cameron@...wei.com>, Dave Jiang <dave.jiang@...el.com>, "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>, Matthew Wilcox <willy@...radead.org>, Jan Kara
	<jack@...e.cz>, "Rafael J . Wysocki" <rafael@...nel.org>, Len Brown
	<len.brown@...el.com>, Pavel Machek <pavel@...nel.org>, Li Ming
	<ming.li@...omail.com>, Jeff Johnson <jeff.johnson@....qualcomm.com>, "Ying
 Huang" <huang.ying.caritas@...il.com>, Yao Xingtao <yaoxt.fnst@...itsu.com>,
	Peter Zijlstra <peterz@...radead.org>, Greg KH <gregkh@...uxfoundation.org>,
	Nathan Fontenot <nathan.fontenot@....com>, Smita Koralahalli
	<Smita.KoralahalliChannabasappa@....com>, Terry Bowman
	<terry.bowman@....com>, Robert Richter <rrichter@....com>, Benjamin Cheatham
	<benjamin.cheatham@....com>, PradeepVineshReddy Kodamati
	<PradeepVineshReddy.Kodamati@....com>, Zhijian Li <lizhijian@...itsu.com>
Subject: [PATCH v5 1/7] cxl/acpi: Refactor cxl_acpi_probe() to always schedule fallback DAX registration

Refactor cxl_acpi_probe() to use a single exit path so that the fallback
DAX registration can be scheduled regardless of probe success or failure.

With CONFIG_CXL_ACPI enabled, future patches will bypass DAX device
registration via the HMAT and hmem drivers. To avoid missing DAX
registration for SOFT RESERVED regions, the fallback path must be
triggered regardless of probe outcome.

No functional changes.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
---
 drivers/cxl/acpi.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index a1a99ec3f12c..ca06d5acdf8f 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -825,7 +825,7 @@ static int pair_cxl_resource(struct device *dev, void *data)
 
 static int cxl_acpi_probe(struct platform_device *pdev)
 {
-	int rc;
+	int rc = 0;
 	struct resource *cxl_res;
 	struct cxl_root *cxl_root;
 	struct cxl_port *root_port;
@@ -837,7 +837,7 @@ static int cxl_acpi_probe(struct platform_device *pdev)
 	rc = devm_add_action_or_reset(&pdev->dev, cxl_acpi_lock_reset_class,
 				      &pdev->dev);
 	if (rc)
-		return rc;
+		goto out;
 
 	cxl_res = devm_kzalloc(host, sizeof(*cxl_res), GFP_KERNEL);
 	if (!cxl_res)
@@ -848,18 +848,20 @@ static int cxl_acpi_probe(struct platform_device *pdev)
 	cxl_res->flags = IORESOURCE_MEM;
 
 	cxl_root = devm_cxl_add_root(host, &acpi_root_ops);
-	if (IS_ERR(cxl_root))
-		return PTR_ERR(cxl_root);
+	if (IS_ERR(cxl_root)) {
+		rc = PTR_ERR(cxl_root);
+		goto out;
+	}
 	root_port = &cxl_root->port;
 
 	rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
 			      add_host_bridge_dport);
 	if (rc < 0)
-		return rc;
+		goto out;
 
 	rc = devm_add_action_or_reset(host, remove_cxl_resources, cxl_res);
 	if (rc)
-		return rc;
+		goto out;
 
 	ctx = (struct cxl_cfmws_context) {
 		.dev = host,
@@ -867,12 +869,14 @@ static int cxl_acpi_probe(struct platform_device *pdev)
 		.cxl_res = cxl_res,
 	};
 	rc = acpi_table_parse_cedt(ACPI_CEDT_TYPE_CFMWS, cxl_parse_cfmws, &ctx);
-	if (rc < 0)
-		return -ENXIO;
+	if (rc < 0) {
+		rc = -ENXIO;
+		goto out;
+	}
 
 	rc = add_cxl_resources(cxl_res);
 	if (rc)
-		return rc;
+		goto out;
 
 	/*
 	 * Populate the root decoders with their related iomem resource,
@@ -887,17 +891,19 @@ static int cxl_acpi_probe(struct platform_device *pdev)
 	rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
 			      add_host_bridge_uport);
 	if (rc < 0)
-		return rc;
+		goto out;
 
 	if (IS_ENABLED(CONFIG_CXL_PMEM))
 		rc = device_for_each_child(&root_port->dev, root_port,
 					   add_root_nvdimm_bridge);
 	if (rc < 0)
-		return rc;
+		goto out;
 
 	/* In case PCI is scanned before ACPI re-trigger memdev attach */
 	cxl_bus_rescan();
-	return 0;
+
+out:
+	return rc;
 }
 
 static const struct acpi_device_id cxl_acpi_ids[] = {
-- 
2.17.1