[PATCH] vduse: make vduse_class constant

[Greg Kroah-Hartman]

Now that the driver core allows for struct class to be in read-only
memory, we should make all 'class' structures declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at runtime.

Cc: "Michael S. Tsirkin" <m...@redhat.com>
Cc: Jason Wang <jasow...@redhat.com>
Cc: Xuan Zhuo <xuanz...@linux.alibaba.com>
Cc: Xie Yongji <xieyon...@bytedance.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 40 ++++++++++++++++--------------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c 
b/drivers/vdpa/vdpa_user/vduse_dev.c
index df7869537ef1..0ddd4b8abecb 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -134,7 +134,6 @@ static DEFINE_MUTEX(vduse_lock);
 static DEFINE_IDR(vduse_idr);
 
 static dev_t vduse_major;
-static struct class *vduse_class;
 static struct cdev vduse_ctrl_cdev;
 static struct cdev vduse_cdev;
 static struct workqueue_struct *vduse_irq_wq;
@@ -1528,6 +1527,16 @@ static const struct kobj_type vq_type = {
        .default_groups = vq_groups,
 };
 
+static char *vduse_devnode(const struct device *dev, umode_t *mode)
+{
+       return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));
+}
+
+static const struct class vduse_class = {
+       .name = "vduse",
+       .devnode = vduse_devnode,
+};
+
 static void vduse_dev_deinit_vqs(struct vduse_dev *dev)
 {
        int i;
@@ -1638,7 +1647,7 @@ static int vduse_destroy_dev(char *name)
        mutex_unlock(&dev->lock);
 
        vduse_dev_reset(dev);
-       device_destroy(vduse_class, MKDEV(MAJOR(vduse_major), dev->minor));
+       device_destroy(&vduse_class, MKDEV(MAJOR(vduse_major), dev->minor));
        idr_remove(&vduse_idr, dev->minor);
        kvfree(dev->config);
        vduse_dev_deinit_vqs(dev);
@@ -1805,7 +1814,7 @@ static int vduse_create_dev(struct vduse_dev_config 
*config,
 
        dev->minor = ret;
        dev->msg_timeout = VDUSE_MSG_DEFAULT_TIMEOUT;
-       dev->dev = device_create_with_groups(vduse_class, NULL,
+       dev->dev = device_create_with_groups(&vduse_class, NULL,
                                MKDEV(MAJOR(vduse_major), dev->minor),
                                dev, vduse_dev_groups, "%s", config->name);
        if (IS_ERR(dev->dev)) {
@@ -1821,7 +1830,7 @@ static int vduse_create_dev(struct vduse_dev_config 
*config,
 
        return 0;
 err_vqs:
-       device_destroy(vduse_class, MKDEV(MAJOR(vduse_major), dev->minor));
+       device_destroy(&vduse_class, MKDEV(MAJOR(vduse_major), dev->minor));
 err_dev:
        idr_remove(&vduse_idr, dev->minor);
 err_idr:
@@ -1934,11 +1943,6 @@ static const struct file_operations vduse_ctrl_fops = {
        .llseek         = noop_llseek,
 };
 
-static char *vduse_devnode(const struct device *dev, umode_t *mode)
-{
-       return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));
-}
-
 struct vduse_mgmt_dev {
        struct vdpa_mgmt_dev mgmt_dev;
        struct device dev;
@@ -2082,11 +2086,9 @@ static int vduse_init(void)
        int ret;
        struct device *dev;
 
-       vduse_class = class_create("vduse");
-       if (IS_ERR(vduse_class))
-               return PTR_ERR(vduse_class);
-
-       vduse_class->devnode = vduse_devnode;
+       ret = class_register(&vduse_class);
+       if (ret)
+               return ret;
 
        ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");
        if (ret)
@@ -2099,7 +2101,7 @@ static int vduse_init(void)
        if (ret)
                goto err_ctrl_cdev;
 
-       dev = device_create(vduse_class, NULL, vduse_major, NULL, "control");
+       dev = device_create(&vduse_class, NULL, vduse_major, NULL, "control");
        if (IS_ERR(dev)) {
                ret = PTR_ERR(dev);
                goto err_device;
@@ -2141,13 +2143,13 @@ static int vduse_init(void)
 err_wq:
        cdev_del(&vduse_cdev);
 err_cdev:
-       device_destroy(vduse_class, vduse_major);
+       device_destroy(&vduse_class, vduse_major);
 err_device:
        cdev_del(&vduse_ctrl_cdev);
 err_ctrl_cdev:
        unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
 err_chardev_region:
-       class_destroy(vduse_class);
+       class_unregister(&vduse_class);
        return ret;
 }
 module_init(vduse_init);
@@ -2159,10 +2161,10 @@ static void vduse_exit(void)
        destroy_workqueue(vduse_irq_bound_wq);
        destroy_workqueue(vduse_irq_wq);
        cdev_del(&vduse_cdev);
-       device_destroy(vduse_class, vduse_major);
+       device_destroy(&vduse_class, vduse_major);
        cdev_del(&vduse_ctrl_cdev);
        unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
-       class_destroy(vduse_class);
+       class_unregister(&vduse_class);
 }
 module_exit(vduse_exit);
 
-- 
2.42.0

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