Subject: [PATCH 1/2] vdpa_sim_blk: switch to dynamic root device

From: Johan Hovold <[email-masked]>
Date: Fri, 24 Apr 2026 12:47:02 +0200

Driver core expects devices to be dynamically allocated and will, for
example, complain loudly when no release function has been provided.

Use root_device_register() to allocate and register the root device
instead of open coding using a static device.

Signed-off-by: Johan Hovold <[email-masked]>
---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index b137f3679343..f70f454dde8e 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -397,14 +397,7 @@ static void vdpasim_blk_free(struct vdpasim *vdpasim)
 		kvfree(blk->buffer);
 }
 
-static void vdpasim_blk_mgmtdev_release(struct device *dev)
-{
-}
-
-static struct device vdpasim_blk_mgmtdev = {
-	.init_name = "vdpasim_blk",
-	.release = vdpasim_blk_mgmtdev_release,
-};
+static struct device *vdpasim_blk_mgmtdev;
 
 static int vdpasim_blk_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 			       const struct vdpa_dev_set_config *config)
@@ -475,7 +468,6 @@ static struct virtio_device_id id_table[] = {
 };
 
 static struct vdpa_mgmt_dev mgmt_dev = {
-	.device = &vdpasim_blk_mgmtdev,
 	.id_table = id_table,
 	.ops = &vdpasim_blk_mgmtdev_ops,
 };
@@ -484,12 +476,11 @@ static int __init vdpasim_blk_init(void)
 {
 	int ret;
 
-	ret = device_register(&vdpasim_blk_mgmtdev);
-	if (ret) {
-		put_device(&vdpasim_blk_mgmtdev);
-		return ret;
-	}
+	vdpasim_blk_mgmtdev = root_device_register("vdpasim_blk");
+	if (IS_ERR(vdpasim_blk_mgmtdev))
+		return PTR_ERR(vdpasim_blk_mgmtdev);
 
+	mgmt_dev.device = vdpasim_blk_mgmtdev;
 	ret = vdpa_mgmtdev_register(&mgmt_dev);
 	if (ret)
 		goto parent_err;
@@ -507,7 +498,8 @@ static int __init vdpasim_blk_init(void)
 mgmt_dev_err:
 	vdpa_mgmtdev_unregister(&mgmt_dev);
 parent_err:
-	device_unregister(&vdpasim_blk_mgmtdev);
+	root_device_unregister(vdpasim_blk_mgmtdev);
+
 	return ret;
 }
 
@@ -515,7 +507,7 @@ static void __exit vdpasim_blk_exit(void)
 {
 	kvfree(shared_buffer);
 	vdpa_mgmtdev_unregister(&mgmt_dev);
-	device_unregister(&vdpasim_blk_mgmtdev);
+	root_device_unregister(vdpasim_blk_mgmtdev);
 }
 
 module_init(vdpasim_blk_init)
-- 
2.53.0