[PATCH v2 4/6] cxl/mem: Convert devm_cxl_add_memdev() to scope-based-cleanup

Dan Williams
2025-12-16T00:55:35Z

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@amd.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
Tested-by: Alejandro Lucero <alucerop@amd.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/cxl/core/memdev.c | 70 ++++++++++++++++++++++++---------------
1 file changed, 44 insertions(+), 26 deletions(-)

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 7a4153e1c6a7..18efbf294db5 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -1050,6 +1050,45 @@ 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);)
+
+static struct cxl_memdev *cxl_memdev_autoremove(struct cxl_memdev *cxlmd)
+{
+ int rc;
+
+ rc = devm_add_action_or_reset(cxlmd->cxlds->dev, cxl_memdev_unregister,
+ cxlmd);
+ if (rc)
+ return ERR_PTR(rc);
+
+ return cxlmd;
+}
+
/*
* 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 +1096,24 @@ 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;
-
- cdev = &cxlmd->cdev;
- rc = cdev_device_add(cdev, dev);
- if (rc)
- goto err;
+ return ERR_PTR(rc);

- rc = devm_add_action_or_reset(host, cxl_memdev_unregister, cxlmd);
+ rc = cxlmd_add(cxlmd, cxlds);
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);
+ return cxl_memdev_autoremove(no_free_ptr(cxlmd));
}
EXPORT_SYMBOL_FOR_MODULES(__devm_cxl_add_memdev, "cxl_mem");

--
2.51.1