drm: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

Because there is no need to check these functions, a number of local
functions can be made to return void to simplify things as nothing can
fail.

Cc: Maarten Lankhorst <[e-mail]>
Cc: Maxime Ripard <[e-mail]>
Cc: Sean Paul <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: [e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/drm_connector.c

···
 	if (ret)
 		goto unlock;
 
-	ret = drm_debugfs_connector_add(connector);
-	if (ret) {
-		goto err_sysfs;
-	}
+	drm_debugfs_connector_add(connector);
 
 	if (connector->funcs->late_register) {
 		ret = connector->funcs->late_register(connector);
···
 
 err_debugfs:
 	drm_debugfs_connector_remove(connector);
-err_sysfs:
 	drm_sysfs_connector_remove(connector);
 unlock:
 	mutex_unlock(&connector->mutex);

drivers/gpu/drm/drm_crtc.c

···
 	int ret = 0;
 
 	drm_for_each_crtc(crtc, dev) {
-		if (drm_debugfs_crtc_add(crtc))
-			DRM_ERROR("Failed to initialize debugfs entry for CRTC '%s'.\n",
-				  crtc->name);
+		drm_debugfs_crtc_add(crtc);
 
 		if (crtc->funcs->late_register)
 			ret = crtc->funcs->late_register(crtc);

drivers/gpu/drm/drm_debugfs.c

···
 	mutex_init(&minor->debugfs_lock);
 	sprintf(name, "%d", minor_id);
 	minor->debugfs_root = debugfs_create_dir(name, root);
-	if (!minor->debugfs_root) {
-		DRM_ERROR("Cannot create /sys/kernel/debug/dri/%s\n", name);
-		return -1;
-	}
 
 	ret = drm_debugfs_create_files(drm_debugfs_list, DRM_DEBUGFS_ENTRIES,
 				       minor->debugfs_root, minor);
···
 	mutex_unlock(&minor->debugfs_lock);
 }
 
-int drm_debugfs_cleanup(struct drm_minor *minor)
+void drm_debugfs_cleanup(struct drm_minor *minor)
 {
 	if (!minor->debugfs_root)
-		return 0;
+		return;
 
 	drm_debugfs_remove_all_files(minor);
 
 	debugfs_remove_recursive(minor->debugfs_root);
 	minor->debugfs_root = NULL;
-
-	return 0;
 }
 
 static int connector_show(struct seq_file *m, void *data)
···
 	.write = connector_write
 };
 
-int drm_debugfs_connector_add(struct drm_connector *connector)
+void drm_debugfs_connector_add(struct drm_connector *connector)
 {
 	struct drm_minor *minor = connector->dev->primary;
-	struct dentry *root, *ent;
+	struct dentry *root;
 
 	if (!minor->debugfs_root)
-		return -1;
+		return;
 
 	root = debugfs_create_dir(connector->name, minor->debugfs_root);
-	if (!root)
-		return -ENOMEM;
-
 	connector->debugfs_entry = root;
 
 	/* force */
-	ent = debugfs_create_file("force", S_IRUGO | S_IWUSR, root, connector,
-				  &drm_connector_fops);
-	if (!ent)
-		goto error;
+	debugfs_create_file("force", S_IRUGO | S_IWUSR, root, connector,
+			    &drm_connector_fops);
 
 	/* edid */
-	ent = debugfs_create_file("edid_override", S_IRUGO | S_IWUSR, root,
-				  connector, &drm_edid_fops);
-	if (!ent)
-		goto error;
-
-	return 0;
-
-error:
-	debugfs_remove_recursive(connector->debugfs_entry);
-	connector->debugfs_entry = NULL;
-	return -ENOMEM;
+	debugfs_create_file("edid_override", S_IRUGO | S_IWUSR, root, connector,
+			    &drm_edid_fops);
 }
 
 void drm_debugfs_connector_remove(struct drm_connector *connector)
···
 	connector->debugfs_entry = NULL;
 }
 
-int drm_debugfs_crtc_add(struct drm_crtc *crtc)
+void drm_debugfs_crtc_add(struct drm_crtc *crtc)
 {
 	struct drm_minor *minor = crtc->dev->primary;
 	struct dentry *root;
···
 
 	name = kasprintf(GFP_KERNEL, "crtc-%d", crtc->index);
 	if (!name)
-		return -ENOMEM;
+		return;
 
 	root = debugfs_create_dir(name, minor->debugfs_root);
 	kfree(name);
-	if (!root)
-		return -ENOMEM;
 
 	crtc->debugfs_entry = root;
 
-	if (drm_debugfs_crtc_crc_add(crtc))
-		goto error;
-
-	return 0;
-
-error:
-	drm_debugfs_crtc_remove(crtc);
-	return -ENOMEM;
+	drm_debugfs_crtc_crc_add(crtc);
 }
 
 void drm_debugfs_crtc_remove(struct drm_crtc *crtc)

drivers/gpu/drm/drm_debugfs_crc.c

···
 	.release = crtc_crc_release,
 };
 
-int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
+void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
 {
-	struct dentry *crc_ent, *ent;
+	struct dentry *crc_ent;
 
 	if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source)
-		return 0;
+		return;
 
 	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);
-	if (!crc_ent)
-		return -ENOMEM;
 
-	ent = debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
-				  &drm_crtc_crc_control_fops);
-	if (!ent)
-		goto error;
-
-	ent = debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
-				  &drm_crtc_crc_data_fops);
-	if (!ent)
-		goto error;
-
-	return 0;
-
-error:
-	debugfs_remove_recursive(crc_ent);
-
-	return -ENOMEM;
+	debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
+			    &drm_crtc_crc_control_fops);
+	debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
+			    &drm_crtc_crc_data_fops);
 }
 
 /**

drivers/gpu/drm/drm_drv.c

···
 	}
 
 	drm_debugfs_root = debugfs_create_dir("dri", NULL);
-	if (!drm_debugfs_root) {
-		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)

drivers/gpu/drm/drm_internal.h

···
 #if defined(CONFIG_DEBUG_FS)
 int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 		     struct dentry *root);
-int drm_debugfs_cleanup(struct drm_minor *minor);
-int drm_debugfs_connector_add(struct drm_connector *connector);
+void drm_debugfs_cleanup(struct drm_minor *minor);
+void drm_debugfs_connector_add(struct drm_connector *connector);
 void drm_debugfs_connector_remove(struct drm_connector *connector);
-int drm_debugfs_crtc_add(struct drm_crtc *crtc);
+void drm_debugfs_crtc_add(struct drm_crtc *crtc);
 void drm_debugfs_crtc_remove(struct drm_crtc *crtc);
-int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc);
+void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc);
 #else
 static inline int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 				   struct dentry *root)
···
 	return 0;
 }
 
-static inline int drm_debugfs_cleanup(struct drm_minor *minor)
+static inline void drm_debugfs_cleanup(struct drm_minor *minor)
 {
-	return 0;
 }
 
-static inline int drm_debugfs_connector_add(struct drm_connector *connector)
+static inline void drm_debugfs_connector_add(struct drm_connector *connector)
 {
-	return 0;
 }
 static inline void drm_debugfs_connector_remove(struct drm_connector *connector)
 {
 }
 
-static inline int drm_debugfs_crtc_add(struct drm_crtc *crtc)
+static inline void drm_debugfs_crtc_add(struct drm_crtc *crtc)
 {
-	return 0;
 }
 static inline void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
 {
 }
 
-static inline int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
+static inline void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
 {
-	return 0;
 }
 
 #endif