drm/i915: Register debugfs interface last

Currently debugfs files are created before the driver is even loads.
This gives the opportunity for userspace to open that interface and poke
around before the backing data structures are initialised - with the
possibility of oopsing or worse.

Move the creation of the debugfs files to our registration phase, where
we announce our presence to the world when we are ready, i.e the
sequence changes from

	drm_dev_register()
	 -> drm_minor_register()
	  -> drm_debugfs_init()
	   -> i915_debugfs_init()
	 -> i915_driver_load()

to

	drm_dev_register()
	 -> drm_minor_register()
	  -> drm_debugfs_init()
	 -> i915_driver_load()
	  -> i915_debugfs_register()

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1466773227-7994-5-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_debugfs.c

@@ -5508,8 +5508,9 @@ void intel_display_crc_init(struct drm_device *dev)
 	}
 }
 
-int i915_debugfs_init(struct drm_minor *minor)
+int i915_debugfs_register(struct drm_i915_private *dev_priv)
 {
+	struct drm_minor *minor = dev_priv->dev->primary;
 	int ret, i;
 
 	ret = i915_forcewake_create(minor->debugfs_root, minor);
@@ -5535,8 +5536,9 @@ int i915_debugfs_init(struct drm_minor *minor)
 					minor->debugfs_root, minor);
 }
 
-void i915_debugfs_cleanup(struct drm_minor *minor)
+void i915_debugfs_unregister(struct drm_i915_private *dev_priv)
 {
+	struct drm_minor *minor = dev_priv->dev->primary;
 	int i;
 
 	drm_debugfs_remove_files(i915_debugfs_list,

drivers/gpu/drm/i915/i915_dma.c

@@ -1397,6 +1397,7 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
 	if (intel_vgpu_active(dev_priv))
 		I915_WRITE(vgtif_reg(display_ready), VGT_DRV_DISPLAY_READY);
 
+	i915_debugfs_register(dev_priv);
 	i915_setup_sysfs(dev);
 	intel_modeset_register(dev_priv);
 
@@ -1433,6 +1434,7 @@ static void i915_driver_unregister(struct drm_i915_private *dev_priv)
 	intel_opregion_unregister(dev_priv);
 	intel_modeset_unregister(dev_priv);
 	i915_teardown_sysfs(dev_priv->dev);
+	i915_debugfs_unregister(dev_priv);
 	i915_gem_shrinker_cleanup(dev_priv);
 }
 

drivers/gpu/drm/i915/i915_drv.c

@@ -1756,10 +1756,6 @@ static struct drm_driver driver = {
 	.postclose = i915_driver_postclose,
 	.set_busid = drm_pci_set_busid,
 
-#if defined(CONFIG_DEBUG_FS)
-	.debugfs_init = i915_debugfs_init,
-	.debugfs_cleanup = i915_debugfs_cleanup,
-#endif
 	.gem_free_object = i915_gem_free_object,
 	.gem_vm_ops = &i915_gem_vm_ops,
 

drivers/gpu/drm/i915/i915_drv.h

@@ -3603,12 +3603,14 @@ int i915_verify_lists(struct drm_device *dev);
 #endif
 
 /* i915_debugfs.c */
-int i915_debugfs_init(struct drm_minor *minor);
-void i915_debugfs_cleanup(struct drm_minor *minor);
 #ifdef CONFIG_DEBUG_FS
+int i915_debugfs_register(struct drm_i915_private *dev_priv);
+void i915_debugfs_unregister(struct drm_i915_private *dev_priv);
 int i915_debugfs_connector_add(struct drm_connector *connector);
 void intel_display_crc_init(struct drm_device *dev);
 #else
+static inline int i915_debugfs_register(struct drm_i915_private *) {return 0;}
+static inline void i915_debugfs_unregister(struct drm_i915_private *) {}
 static inline int i915_debugfs_connector_add(struct drm_connector *connector)
 { return 0; }
 static inline void intel_display_crc_init(struct drm_device *dev) {}