Various cleanups to the DRM core initialization and exit handlers:

 - Register chrdev last: Once register_chrdev() returns, open() will
   succeed on the given chrdevs. This is usually not an issue, as no
   chardevs are registered, yet. However, nodes can be created by
   user-space via mknod(2), even though such major/minor combinations are
   unknown to the kernel. Avoid calling into drm_stub_open() in those
   cases.
   Again, drm_stub_open() would just bail out as the inode is unknown,
   but it's really non-obvious if you hack on drm_stub_open().

 - Unify error-paths into just one label. All the error-path helpers can
   be called even though the constructors were not called yet, or failed.
   Hence, just call all cleanups unconditionally.

 - Call into drm_global_release(). This is a no-op, but provides
   debugging helpers in case there're GLOBALS left on module unload. This
   function was unused until now.

 - Use DRM_ERROR() instead of printk(), and also print the error-code on
   failure (even if it is static!).

 - Don't throw away error-codes of register_chrdev()!

 - Don't hardcode -1 as errno. This is just plain wrong.

 - Order exit-handlers in the exact reverse order of initialization
   (except if the order actually matters for syncing-reasons, which is
   not the case here, though).

Signed-off-by: David Herrmann <dh.herrmann at gmail.com>
---
 drivers/gpu/drm/drm_drv.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 58299f7..bf2924b 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -829,50 +829,50 @@ static const struct file_operations drm_stub_fops = {

 static int __init drm_core_init(void)
 {
-       int ret = -ENOMEM;
+       int ret;

        drm_global_init();
        drm_connector_ida_init();
        idr_init(&drm_minors_idr);

-       if (register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops))
-               goto err_p1;
-
        ret = drm_sysfs_init();
        if (ret < 0) {
-               printk(KERN_ERR "DRM: Error creating drm class.\n");
-               goto err_p2;
+               DRM_ERROR("Cannot create DRM class: %d\n", ret);
+               goto error;
        }

        drm_debugfs_root = debugfs_create_dir("dri", NULL);
        if (!drm_debugfs_root) {
-               DRM_ERROR("Cannot create /sys/kernel/debug/dri\n");
-               ret = -1;
-               goto err_p3;
+               ret = -ENOMEM;
+               DRM_ERROR("Cannot create debugfs-root: %d\n", ret);
+               goto error;
        }

+       ret = register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops);
+       if (ret < 0)
+               goto error;
+
        DRM_INFO("Initialized %s %d.%d.%d %s\n",
                 CORE_NAME, CORE_MAJOR, CORE_MINOR, CORE_PATCHLEVEL, CORE_DATE);
        return 0;
-err_p3:
-       drm_sysfs_destroy();
-err_p2:
-       unregister_chrdev(DRM_MAJOR, "drm");

+error:
+       debugfs_remove(drm_debugfs_root);
+       drm_sysfs_destroy();
        idr_destroy(&drm_minors_idr);
-err_p1:
+       drm_connector_ida_destroy();
+       drm_global_release();
        return ret;
 }

 static void __exit drm_core_exit(void)
 {
+       unregister_chrdev(DRM_MAJOR, "drm");
        debugfs_remove(drm_debugfs_root);
        drm_sysfs_destroy();
-
-       unregister_chrdev(DRM_MAJOR, "drm");
-
-       drm_connector_ida_destroy();
        idr_destroy(&drm_minors_idr);
+       drm_connector_ida_destroy();
+       drm_global_release();
 }

 module_init(drm_core_init);
-- 
2.5.1

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