drm/fb-helper: Export drm_fb_helper_release_info()

Export the fb_info release code as drm_fb_helper_release_info(). Will
help with cleaning up failed fbdev probing.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Zack Rusin <zackr@vmware.com>
Tested-by: Sui Jingfeng<suijingfeng@loongson.cn>
Link: https://patchwork.freedesktop.org/patch/msgid/20230320150751.20399-4-tzimmermann@suse.de

drivers/gpu/drm/drm_fb_helper.c

@@ -538,6 +538,29 @@ struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
 }
 EXPORT_SYMBOL(drm_fb_helper_alloc_info);
 
+/**
+ * drm_fb_helper_release_info - release fb_info and its members
+ * @fb_helper: driver-allocated fbdev helper
+ *
+ * A helper to release fb_info and the member cmap.  Drivers do not
+ * need to release the allocated fb_info structure themselves, this is
+ * automatically done when calling drm_fb_helper_fini().
+ */
+void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
+{
+	struct fb_info *info = fb_helper->info;
+
+	if (!info)
+		return;
+
+	fb_helper->info = NULL;
+
+	if (info->cmap.len)
+		fb_dealloc_cmap(&info->cmap);
+	framebuffer_release(info);
+}
+EXPORT_SYMBOL(drm_fb_helper_release_info);
+
 /**
  * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
  * @fb_helper: driver-allocated fbdev helper, can be NULL
@@ -561,8 +584,6 @@ EXPORT_SYMBOL(drm_fb_helper_unregister_info);
  */
 void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
 {
-	struct fb_info *info;
-
 	if (!fb_helper)
 		return;
 
@@ -574,13 +595,7 @@ void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
 	cancel_work_sync(&fb_helper->resume_work);
 	cancel_work_sync(&fb_helper->damage_work);
 
-	info = fb_helper->info;
-	if (info) {
-		if (info->cmap.len)
-			fb_dealloc_cmap(&info->cmap);
-		framebuffer_release(info);
-	}
-	fb_helper->info = NULL;
+	drm_fb_helper_release_info(fb_helper);
 
 	mutex_lock(&kernel_fb_helper_lock);
 	if (!list_empty(&fb_helper->kernel_fb_list)) {

include/drm/drm_fb_helper.h

@@ -256,6 +256,7 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
 int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper);
 
 struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper);
+void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper);
 void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper);
 void drm_fb_helper_fill_info(struct fb_info *info,
 			     struct drm_fb_helper *fb_helper,
@@ -365,6 +366,10 @@ drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
 	return NULL;
 }
 
+static inline void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
+{
+}
+
 static inline void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
 {
 }