1 files changed, 77 insertions, 32 deletions

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index e370d733e440..af3d0cc65138 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -27,7 +27,6 @@ static void cxl_memdev_release(struct device *dev)
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 
 	ida_free(&cxl_memdev_ida, cxlmd->id);
-	devm_cxl_memdev_edac_release(cxlmd);
 	kfree(cxlmd);
 }
 
@@ -642,14 +641,24 @@ static void detach_memdev(struct work_struct *work)
 	struct cxl_memdev *cxlmd;
 
 	cxlmd = container_of(work, typeof(*cxlmd), detach_work);
-	device_release_driver(&cxlmd->dev);
+
+	/*
+	 * When the creator of @cxlmd sets ->attach it indicates CXL operation
+	 * is required. In that case, @cxlmd detach escalates to parent device
+	 * detach.
+	 */
+	if (cxlmd->attach)
+		device_release_driver(cxlmd->dev.parent);
+	else
+		device_release_driver(&cxlmd->dev);
 	put_device(&cxlmd->dev);
 }
 
 static struct lock_class_key cxl_memdev_key;
 
 static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds,
-					   const struct file_operations *fops)
+					   const struct file_operations *fops,
+					   const struct cxl_memdev_attach *attach)
 {
 	struct cxl_memdev *cxlmd;
 	struct device *dev;
@@ -665,6 +674,8 @@ static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds,
 		goto err;
 	cxlmd->id = rc;
 	cxlmd->depth = -1;
+	cxlmd->attach = attach;
+	cxlmd->endpoint = ERR_PTR(-ENXIO);
 
 	dev = &cxlmd->dev;
 	device_initialize(dev);
@@ -1051,50 +1062,84 @@ static const struct file_operations cxl_memdev_fops = {
 	.llseek = noop_llseek,
 };
 
-struct cxl_memdev *devm_cxl_add_memdev(struct device *host,
-				       struct cxl_dev_state *cxlds)
+/*
+ * 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;
+
+	/*
+	 * If @attach is provided fail if the driver is not attached upon
+	 * return. Note that failure here could be the result of a race to
+	 * teardown the CXL port topology. I.e. cxl_mem_probe() could have
+	 * succeeded and then cxl_mem unbound before the lock is acquired.
+	 */
+	guard(device)(&cxlmd->dev);
+	if (cxlmd->attach && !cxlmd->dev.driver) {
+		cxl_memdev_unregister(cxlmd);
+		return ERR_PTR(-ENXIO);
+	}
+
+	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.
+ */
+struct cxl_memdev *__devm_cxl_add_memdev(struct cxl_dev_state *cxlds,
+					 const struct cxl_memdev_attach *attach)
 {
-	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, attach);
 	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_NS_GPL(devm_cxl_add_memdev, "CXL");
+EXPORT_SYMBOL_FOR_MODULES(__devm_cxl_add_memdev, "cxl_mem");
 
 static void sanitize_teardown_notifier(void *data)
 {