[PATCH v2] vdpa: regist vhost-vdpa dev class

[Yi Wang <wang.yi59@zte.com.cn>]

From: Zhang Min <zhang.min9@zte.com.cn>

Some applications like kata-containers need to acquire MAJOR/MINOR/DEVNAME
for devInfo [1], so regist vhost-vdpa dev class to expose uevent.

1. https://github.com/kata-containers/kata-containers/blob/main/src/runtime/virtcontainers/device/config/config.go

Signed-off-by: Zhang Min <zhang.min9@zte.com.cn>
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
---
v2: remove redundant vhost_vdpa_class reset and pr_warn, adjust location
    of *vhost_vdpa_class impl and class_destroy.

 drivers/vhost/vdpa.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index e3c4f059b21a..55e966c508c8 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -53,6 +53,7 @@ struct vhost_vdpa {
 static DEFINE_IDA(vhost_vdpa_ida);
 
 static dev_t vhost_vdpa_major;
+static struct class *vhost_vdpa_class;
 
 static void handle_vq_kick(struct vhost_work *work)
 {
@@ -1140,6 +1141,7 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
 	v->dev.release = vhost_vdpa_release_dev;
 	v->dev.parent = &vdpa->dev;
 	v->dev.devt = MKDEV(MAJOR(vhost_vdpa_major), minor);
+	v->dev.class = vhost_vdpa_class;
 	v->vqs = kmalloc_array(v->nvqs, sizeof(struct vhost_virtqueue),
 			       GFP_KERNEL);
 	if (!v->vqs) {
@@ -1197,6 +1199,10 @@ static int __init vhost_vdpa_init(void)
 {
 	int r;
 
+	vhost_vdpa_class = class_create(THIS_MODULE, "vhost-vdpa");
+	if (IS_ERR(vhost_vdpa_class))
+		return PTR_ERR(vhost_vdpa_class);
+
 	r = alloc_chrdev_region(&vhost_vdpa_major, 0, VHOST_VDPA_DEV_MAX,
 				"vhost-vdpa");
 	if (r)
@@ -1211,6 +1217,7 @@ static int __init vhost_vdpa_init(void)
 err_vdpa_register_driver:
 	unregister_chrdev_region(vhost_vdpa_major, VHOST_VDPA_DEV_MAX);
 err_alloc_chrdev:
+	class_destroy(vhost_vdpa_class);
 	return r;
 }
 module_init(vhost_vdpa_init);
@@ -1219,6 +1226,7 @@ static void __exit vhost_vdpa_exit(void)
 {
 	vdpa_unregister_driver(&vhost_vdpa_driver);
 	unregister_chrdev_region(vhost_vdpa_major, VHOST_VDPA_DEV_MAX);
+	class_destroy(vhost_vdpa_class);
 }
 module_exit(vhost_vdpa_exit);
 
-- 
2.27.0