linux-kernel - [PATCH 4/6] cxl/mem: Convert devm_cxl_add

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Message-ID: <20251204022136.2573521-5-dan.j.williams@intel.com>
Date: Wed,  3 Dec 2025 18:21:34 -0800
From: Dan Williams <dan.j.williams@...el.com>
To: dave.jiang@...el.com
Cc: linux-cxl@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Smita.KoralahalliChannabasappa@....com,
	alison.schofield@...el.com,
	terry.bowman@....com,
	alejandro.lucero-palau@....com,
	linux-pci@...r.kernel.org,
	Jonathan.Cameron@...wei.com,
	Alejandro Lucero <alucerop@....com>
Subject: [PATCH 4/6] cxl/mem: Convert devm_cxl_add_memdev() to scope-based-cleanup

In preparation for adding more setup steps, convert the current
implementation to scope-based cleanup.

The cxl_memdev_shutdown() is only required after cdev_device_add(). With
that moved to a helper function it precludes the need to add
scope-based-handler for that cleanup if devm_add_action_or_reset() fails.

Cc: Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
Cc: Alejandro Lucero <alucerop@....com>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
 drivers/cxl/core/memdev.c | 58 +++++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 24 deletions(-)

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 7a4153e1c6a7..d0efc9ceda2a 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -1050,6 +1050,33 @@ static const struct file_operations cxl_memdev_fops = {
 	.llseek = noop_llseek,
 };
 
+/*
+ * Activate ioctl operations, no cxl_memdev_rwsem manipulation needed as this is
+ * ordered with cdev_add() publishing the device.
+ */
+static int cxlmd_add(struct cxl_memdev *cxlmd, struct cxl_dev_state *cxlds)
+{
+	int rc;
+
+	cxlmd->cxlds = cxlds;
+	cxlds->cxlmd = cxlmd;
+
+	rc = cdev_device_add(&cxlmd->cdev, &cxlmd->dev);
+	if (rc) {
+		/*
+		 * The cdev was briefly live, shutdown any ioctl operations that
+		 * saw that state.
+		 */
+		cxl_memdev_shutdown(&cxlmd->dev);
+		return rc;
+	}
+
+	return 0;
+}
+
+DEFINE_FREE(put_cxlmd, struct cxl_memdev *,
+	    if (!IS_ERR_OR_NULL(_T)) put_device(&_T->dev);)
+
 /*
  * Core helper for devm_cxl_add_memdev() that wants to both create a device and
  * assert to the caller that upon return cxl_mem::probe() has been invoked.
@@ -1057,45 +1084,28 @@ static const struct file_operations cxl_memdev_fops = {
 struct cxl_memdev *__devm_cxl_add_memdev(struct device *host,
 					 struct cxl_dev_state *cxlds)
 {
-	struct cxl_memdev *cxlmd;
 	struct device *dev;
-	struct cdev *cdev;
 	int rc;
 
-	cxlmd = cxl_memdev_alloc(cxlds, &cxl_memdev_fops);
+	struct cxl_memdev *cxlmd __free(put_cxlmd) =
+		cxl_memdev_alloc(cxlds, &cxl_memdev_fops);
 	if (IS_ERR(cxlmd))
 		return cxlmd;
 
 	dev = &cxlmd->dev;
 	rc = dev_set_name(dev, "mem%d", cxlmd->id);
 	if (rc)
-		goto err;
-
-	/*
-	 * Activate ioctl operations, no cxl_memdev_rwsem manipulation
-	 * needed as this is ordered with cdev_add() publishing the device.
-	 */
-	cxlmd->cxlds = cxlds;
-	cxlds->cxlmd = cxlmd;
+		return ERR_PTR(rc);
 
-	cdev = &cxlmd->cdev;
-	rc = cdev_device_add(cdev, dev);
+	rc = cxlmd_add(cxlmd, cxlds);
 	if (rc)
-		goto err;
+		return ERR_PTR(rc);
 
-	rc = devm_add_action_or_reset(host, cxl_memdev_unregister, cxlmd);
+	rc = devm_add_action_or_reset(host, cxl_memdev_unregister,
+				      no_free_ptr(cxlmd));
 	if (rc)
 		return ERR_PTR(rc);
 	return cxlmd;
-
-err:
-	/*
-	 * The cdev was briefly live, shutdown any ioctl operations that
-	 * saw that state.
-	 */
-	cxl_memdev_shutdown(dev);
-	put_device(dev);
-	return ERR_PTR(rc);
 }
 EXPORT_SYMBOL_FOR_MODULES(__devm_cxl_add_memdev, "cxl_mem");
 
-- 
2.51.1