fbdev/core: Add fb_device_{create,destroy}()

Move the logic to create and destroy fbdev devices into the new
helpers fb_device_create() and fb_device_destroy().

There was a call to fb_cleanup_device() in do_unregister_framebuffer()
that was too late. The device had already been removed at this point.
Move the call into fb_device_destroy().

Declare the helpers in the new internal header file  fb_internal.h, as
they are only used 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/20230613110953.24176-35-tzimmermann@suse.de

drivers/video/fbdev/core/fb_internal.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _FB_INTERNAL_H
+#define _FB_INTERNAL_H
+
+struct fb_info;
+
+/* fbsysfs.c */
+int fb_device_create(struct fb_info *fb_info);
+void fb_device_destroy(struct fb_info *fb_info);
+
+#endif

drivers/video/fbdev/core/fbmem.c

@@ -40,6 +40,8 @@
 #include <video/nomodeset.h>
 #include <video/vga.h>
 
+#include "fb_internal.h"
+
     /*
      *  Frame buffer device initialization and setup routines
      */
@@ -1447,14 +1449,7 @@ static int do_register_framebuffer(struct fb_info *fb_info)
 	mutex_init(&fb_info->lock);
 	mutex_init(&fb_info->mm_lock);
 
-	fb_info->dev = device_create(fb_class, fb_info->device,
-				     MKDEV(FB_MAJOR, i), NULL, "fb%d", i);
-	if (IS_ERR(fb_info->dev)) {
-		/* Not fatal */
-		printk(KERN_WARNING "Unable to create device for framebuffer %d; errno = %ld\n", i, PTR_ERR(fb_info->dev));
-		fb_info->dev = NULL;
-	} else
-		fb_init_device(fb_info);
+	fb_device_create(fb_info);
 
 	if (fb_info->pixmap.addr == NULL) {
 		fb_info->pixmap.addr = kmalloc(FBPIXMAPSIZE, GFP_KERNEL);
@@ -1515,16 +1510,9 @@ static void unlink_framebuffer(struct fb_info *fb_info)
 	if (WARN_ON(i < 0 || i >= FB_MAX || registered_fb[i] != fb_info))
 		return;
 
-	if (!fb_info->dev)
-		return;
-
-	device_destroy(fb_class, MKDEV(FB_MAJOR, i));
-
+	fb_device_destroy(fb_info);
 	pm_vt_switch_unregister(fb_info->device);
-
 	unbind_console(fb_info);
-
-	fb_info->dev = NULL;
 }
 
 static void do_unregister_framebuffer(struct fb_info *fb_info)
@@ -1539,7 +1527,6 @@ static void do_unregister_framebuffer(struct fb_info *fb_info)
 	fb_destroy_modelist(&fb_info->modelist);
 	registered_fb[fb_info->node] = NULL;
 	num_registered_fb--;
-	fb_cleanup_device(fb_info);
 #ifdef CONFIG_GUMSTIX_AM200EPD
 	{
 		struct fb_event event;

drivers/video/fbdev/core/fbsysfs.c

@@ -8,6 +8,9 @@
 #include <linux/console.h>
 #include <linux/fb.h>
 #include <linux/fbcon.h>
+#include <linux/major.h>
+
+#include "fb_internal.h"
 
 #define FB_SYSFS_FLAG_ATTR 1
 
@@ -435,7 +438,7 @@ static struct device_attribute device_attrs[] = {
 #endif
 };
 
-int fb_init_device(struct fb_info *fb_info)
+static int fb_init_device(struct fb_info *fb_info)
 {
 	int i, error = 0;
 
@@ -459,7 +462,7 @@ int fb_init_device(struct fb_info *fb_info)
 	return 0;
 }
 
-void fb_cleanup_device(struct fb_info *fb_info)
+static void fb_cleanup_device(struct fb_info *fb_info)
 {
 	unsigned int i;
 
@@ -470,3 +473,34 @@ void fb_cleanup_device(struct fb_info *fb_info)
 		fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
 	}
 }
+
+int fb_device_create(struct fb_info *fb_info)
+{
+	int node = fb_info->node;
+	dev_t devt = MKDEV(FB_MAJOR, node);
+	int ret;
+
+	fb_info->dev = device_create(fb_class, fb_info->device, devt, NULL, "fb%d", node);
+	if (IS_ERR(fb_info->dev)) {
+		/* Not fatal */
+		ret = PTR_ERR(fb_info->dev);
+		pr_warn("Unable to create device for framebuffer %d; error %d\n", node, ret);
+		fb_info->dev = NULL;
+	} else {
+		fb_init_device(fb_info);
+	}
+
+	return 0;
+}
+
+void fb_device_destroy(struct fb_info *fb_info)
+{
+	dev_t devt = MKDEV(FB_MAJOR, fb_info->node);
+
+	if (!fb_info->dev)
+		return;
+
+	fb_cleanup_device(fb_info);
+	device_destroy(fb_class, devt);
+	fb_info->dev = NULL;
+}

include/linux/fb.h

@@ -735,11 +735,8 @@ static inline bool fb_be_math(struct fb_info *info)
 #endif /* CONFIG_FB_FOREIGN_ENDIAN */
 }
 
-/* drivers/video/fbsysfs.c */
 extern struct fb_info *framebuffer_alloc(size_t size, struct device *dev);
 extern void framebuffer_release(struct fb_info *info);
-extern int fb_init_device(struct fb_info *fb_info);
-extern void fb_cleanup_device(struct fb_info *head);
 extern void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max);
 
 /* drivers/video/fbmon.c */