fbdev/core: Rework fb init code

Init the class "graphics" before the rest of fbdev. Later steps, such
as the sysfs code, depend on the class. Also arrange the module's exit
code in reverse order.

Unexport the global variable fb_class, which is only shared internally
within the fbdev core module.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-38-tzimmermann@suse.de

drivers/video/fbdev/core/fb_internal.h

@@ -11,6 +11,7 @@ int fb_register_chrdev(void);
 void fb_unregister_chrdev(void);
 
 /* fbmem.c */
+extern struct class *fb_class;
 extern struct mutex registration_lock;
 extern struct fb_info *registered_fb[FB_MAX];
 extern int num_registered_fb;

drivers/video/fbdev/core/fbcon.c

@@ -78,6 +78,7 @@
 #include <asm/irq.h>
 
 #include "fbcon.h"
+#include "fb_internal.h"
 
 /*
  * FIXME: Locking

drivers/video/fbdev/core/fbmem.c

@@ -44,6 +44,8 @@
 
 #define FBPIXMAPSIZE	(1024 * 8)
 
+struct class *fb_class;
+
 DEFINE_MUTEX(registration_lock);
 struct fb_info *registered_fb[FB_MAX] __read_mostly;
 int num_registered_fb __read_mostly;
@@ -899,9 +901,6 @@ fb_blank(struct fb_info *info, int blank)
 }
 EXPORT_SYMBOL(fb_blank);
 
-struct class *fb_class;
-EXPORT_SYMBOL(fb_class);
-
 static int fb_check_foreignness(struct fb_info *fi)
 {
 	const bool foreign_endian = fi->flags & FBINFO_FOREIGN_ENDIAN;
@@ -1108,59 +1107,48 @@ void fb_set_suspend(struct fb_info *info, int state)
 }
 EXPORT_SYMBOL(fb_set_suspend);
 
-/**
- *	fbmem_init - init frame buffer subsystem
- *
- *	Initialize the frame buffer subsystem.
- *
- *	NOTE: This function is _only_ to be called by drivers/char/mem.c.
- *
- */
-
-static int __init
-fbmem_init(void)
+static int __init fbmem_init(void)
 {
 	int ret;
 
+	fb_class = class_create("graphics");
+	if (IS_ERR(fb_class)) {
+		ret = PTR_ERR(fb_class);
+		pr_err("Unable to create fb class; errno = %d\n", ret);
+		goto err_fb_class;
+	}
+
 	ret = fb_init_procfs();
 	if (ret)
-		return ret;
+		goto err_class_destroy;
 
 	ret = fb_register_chrdev();
 	if (ret)
-		goto err_chrdev;
-
-	fb_class = class_create("graphics");
-	if (IS_ERR(fb_class)) {
-		ret = PTR_ERR(fb_class);
-		pr_warn("Unable to create fb class; errno = %d\n", ret);
-		fb_class = NULL;
-		goto err_class;
-	}
+		goto err_fb_cleanup_procfs;
 
 	fb_console_init();
 
 	return 0;
 
-err_class:
-	fb_unregister_chrdev();
-err_chrdev:
+err_fb_cleanup_procfs:
 	fb_cleanup_procfs();
+err_class_destroy:
+	class_destroy(fb_class);
+err_fb_class:
+	fb_class = NULL;
 	return ret;
 }
 
 #ifdef MODULE
-module_init(fbmem_init);
-static void __exit
-fbmem_exit(void)
+static void __exit fbmem_exit(void)
 {
 	fb_console_exit();
-
+	fb_unregister_chrdev();
 	fb_cleanup_procfs();
 	class_destroy(fb_class);
-	fb_unregister_chrdev();
 }
 
+module_init(fbmem_init);
 module_exit(fbmem_exit);
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Framebuffer base");

include/linux/fb.h

@@ -609,7 +609,6 @@ extern int fb_new_modelist(struct fb_info *info);
 
 extern bool fb_center_logo;
 extern int fb_logo_count;
-extern struct class *fb_class;
 
 static inline void lock_fb_info(struct fb_info *info)
 {