[PATCH v2 1/3] driver core: platform: remove software node on release()

[Bartosz Golaszewski]

If we pass a software node to a newly created device using struct
platform_device_info, it will not be removed when the device is
released. This may happen when a module creating the device is removed
or on failure in platform_device_add().

When we try to reuse that software node in a subsequent call to
platform_device_register_full(), it will fails with -EBUSY. Add the
missing call to device_remove_software_node() in release path.

Make sure that we still function correctly if a software node is used as
the primary firmware node.

Fixes: 0fc434bc2c45 ("driver core: platform: allow attaching software nodes when creating devices")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
 drivers/base/platform.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 75b4698d0e582e67adafa78c312d75c72fd654cf..43ea7dcd338dd3ddae57e6d0677e5cb2673f6ed5 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -599,6 +599,7 @@ static void platform_device_release(struct device *dev)
 	struct platform_object *pa = container_of(dev, struct platform_object,
 						  pdev.dev);
 
+	device_remove_software_node(dev);
 	of_node_put(pa->pdev.dev.of_node);
 	kfree(pa->pdev.dev.platform_data);
 	kfree(pa->pdev.mfd_cell);
@@ -885,6 +886,16 @@ struct platform_device *platform_device_register_full(const struct platform_devi
 			goto err;
 	}
 
+	/*
+	 * If the primary firmware node is a software node and there's no
+	 * secondary firmware node, the primary will be affected by the call
+	 * to device_remove_software_node() in platform_device_release() and
+	 * its reference count will be dropped by one. Take another reference
+	 * here to make it have no effect.
+	 */
+	if (is_software_node(pdevinfo->fwnode) && !pdevinfo->swnode)
+		fwnode_handle_get(pdevinfo->fwnode);
+
 	ret = platform_device_add(pdev);
 	if (ret) {
 err:

-- 
2.47.3