1 files changed, 33 insertions, 37 deletions

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 1eab4ace0671..21271d8df023 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -22,6 +22,7 @@
 #include <linux/idr.h>
 #include <linux/iommu.h>
 #include <linux/list.h>
+#include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/rwsem.h>
@@ -45,9 +46,7 @@ static struct vfio {
         struct idr                      group_idr;
         struct mutex                    group_lock;
         struct cdev                     group_cdev;
-        struct device                   *dev;
-        dev_t                           devt;
-        struct cdev                     cdev;
+        dev_t                           group_devt;
         wait_queue_head_t               release_q;
 } vfio;
 
@@ -142,8 +141,7 @@ EXPORT_SYMBOL_GPL(vfio_unregister_iommu_driver);
  */
 static int vfio_alloc_group_minor(struct vfio_group *group)
 {
-        /* index 0 is used by /dev/vfio/vfio */
-        return idr_alloc(&vfio.group_idr, group, 1, MINORMASK + 1, GFP_KERNEL);
+        return idr_alloc(&vfio.group_idr, group, 0, MINORMASK + 1, GFP_KERNEL);
 }
 
 static void vfio_free_group_minor(int minor)
@@ -243,7 +241,8 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
                 }
         }
 
-        dev = device_create(vfio.class, NULL, MKDEV(MAJOR(vfio.devt), minor),
+        dev = device_create(vfio.class, NULL,
+                            MKDEV(MAJOR(vfio.group_devt), minor),
                             group, "%d", iommu_group_id(iommu_group));
         if (IS_ERR(dev)) {
                 vfio_free_group_minor(minor);
@@ -268,7 +267,7 @@ static void vfio_group_release(struct kref *kref)
 
         WARN_ON(!list_empty(&group->device_list));
 
-        device_destroy(vfio.class, MKDEV(MAJOR(vfio.devt), group->minor));
+        device_destroy(vfio.class, MKDEV(MAJOR(vfio.group_devt), group->minor));
         list_del(&group->vfio_next);
         vfio_free_group_minor(group->minor);
         vfio_group_unlock_and_free(group);
@@ -1419,12 +1418,17 @@ EXPORT_SYMBOL_GPL(vfio_external_user_iommu_id);
  */
 static char *vfio_devnode(struct device *dev, umode_t *mode)
 {
-        if (mode && (MINOR(dev->devt) == 0))
-                *mode = S_IRUGO | S_IWUGO;
-
         return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
 }
 
+static struct miscdevice vfio_dev = {
+        .minor = VFIO_MINOR,
+        .name = "vfio",
+        .fops = &vfio_fops,
+        .nodename = "vfio/vfio",
+        .mode = S_IRUGO | S_IWUGO,
+};
+
 static int __init vfio_init(void)
 {
         int ret;
@@ -1436,6 +1440,13 @@ static int __init vfio_init(void)
         INIT_LIST_HEAD(&vfio.iommu_drivers_list);
         init_waitqueue_head(&vfio.release_q);
 
+        ret = misc_register(&vfio_dev);
+        if (ret) {
+                pr_err("vfio: misc device register failed\n");
+                return ret;
+        }
+
+        /* /dev/vfio/$GROUP */
         vfio.class = class_create(THIS_MODULE, "vfio");
         if (IS_ERR(vfio.class)) {
                 ret = PTR_ERR(vfio.class);
@@ -1444,27 +1455,14 @@ static int __init vfio_init(void)
 
         vfio.class->devnode = vfio_devnode;
 
-        ret = alloc_chrdev_region(&vfio.devt, 0, MINORMASK, "vfio");
-        if (ret)
-                goto err_base_chrdev;
-
-        cdev_init(&vfio.cdev, &vfio_fops);
-        ret = cdev_add(&vfio.cdev, vfio.devt, 1);
+        ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK, "vfio");
         if (ret)
-                goto err_base_cdev;
+                goto err_alloc_chrdev;
 
-        vfio.dev = device_create(vfio.class, NULL, vfio.devt, NULL, "vfio");
-        if (IS_ERR(vfio.dev)) {
-                ret = PTR_ERR(vfio.dev);
-                goto err_base_dev;
-        }
-
-        /* /dev/vfio/$GROUP */
         cdev_init(&vfio.group_cdev, &vfio_group_fops);
-        ret = cdev_add(&vfio.group_cdev,
-                       MKDEV(MAJOR(vfio.devt), 1), MINORMASK - 1);
+        ret = cdev_add(&vfio.group_cdev, vfio.group_devt, MINORMASK);
         if (ret)
-                goto err_groups_cdev;
+                goto err_cdev_add;
 
         pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
 
@@ -1478,16 +1476,13 @@ static int __init vfio_init(void)
 
         return 0;
 
-err_groups_cdev:
-        device_destroy(vfio.class, vfio.devt);
-err_base_dev:
-        cdev_del(&vfio.cdev);
-err_base_cdev:
-        unregister_chrdev_region(vfio.devt, MINORMASK);
-err_base_chrdev:
+err_cdev_add:
+        unregister_chrdev_region(vfio.group_devt, MINORMASK);
+err_alloc_chrdev:
         class_destroy(vfio.class);
         vfio.class = NULL;
 err_class:
+        misc_deregister(&vfio_dev);
         return ret;
 }
 
@@ -1497,11 +1492,10 @@ static void __exit vfio_cleanup(void)
 
         idr_destroy(&vfio.group_idr);
         cdev_del(&vfio.group_cdev);
-        device_destroy(vfio.class, vfio.devt);
-        cdev_del(&vfio.cdev);
-        unregister_chrdev_region(vfio.devt, MINORMASK);
+        unregister_chrdev_region(vfio.group_devt, MINORMASK);
         class_destroy(vfio.class);
         vfio.class = NULL;
+        misc_deregister(&vfio_dev);
 }
 
 module_init(vfio_init);
@@ -1511,3 +1505,5 @@ MODULE_VERSION(DRIVER_VERSION);
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_ALIAS_MISCDEV(VFIO_MINOR);
+MODULE_ALIAS("devname:vfio/vfio");