fbdev/core: Move procfs code to separate file

Move fbdev's procfs code into a separate file and contain it in
init and cleanup helpers. For the cleanup, replace remove_proc_entry()
with proc_remove(). It is equivalent in functionality, but looks
more like an inverse of proc_create_seq().

v2:
	* document proc_remove() usage (Sam)
	* revert unrelated removal of for_each_registered_fb()
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-36-tzimmermann@suse.de

drivers/video/fbdev/core/Makefile

@@ -3,6 +3,7 @@ obj-$(CONFIG_FB_NOTIFY)           += fb_notify.o
 obj-$(CONFIG_FB)                  += fb.o
 fb-y                              := fb_backlight.o \
                                      fb_info.o \
+                                     fb_procfs.o \
                                      fbmem.o fbmon.o fbcmap.o fbsysfs.o \
                                      modedb.o fbcvt.o fb_cmdline.o fb_io_fops.o
 fb-$(CONFIG_FB_DEFERRED_IO)       += fb_defio.o

drivers/video/fbdev/core/fb_internal.h

@@ -3,7 +3,17 @@
 #ifndef _FB_INTERNAL_H
 #define _FB_INTERNAL_H
 
-struct fb_info;
+#include <linux/fb.h>
+#include <linux/mutex.h>
+
+/* fbmem.c */
+extern struct mutex registration_lock;
+extern struct fb_info *registered_fb[FB_MAX];
+extern int num_registered_fb;
+
+/* fb_procfs.c */
+int fb_init_procfs(void);
+void fb_cleanup_procfs(void);
 
 /* fbsysfs.c */
 int fb_device_create(struct fb_info *fb_info);

drivers/video/fbdev/core/fb_procfs.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/proc_fs.h>
+
+#include "fb_internal.h"
+
+static struct proc_dir_entry *fb_proc_dir_entry;
+
+static void *fb_seq_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&registration_lock);
+
+	return (*pos < FB_MAX) ? pos : NULL;
+}
+
+static void fb_seq_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&registration_lock);
+}
+
+static void *fb_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	(*pos)++;
+
+	return (*pos < FB_MAX) ? pos : NULL;
+}
+
+static int fb_seq_show(struct seq_file *m, void *v)
+{
+	int i = *(loff_t *)v;
+	struct fb_info *fi = registered_fb[i];
+
+	if (fi)
+		seq_printf(m, "%d %s\n", fi->node, fi->fix.id);
+
+	return 0;
+}
+
+static const struct seq_operations __maybe_unused fb_proc_seq_ops = {
+	.start	= fb_seq_start,
+	.stop	= fb_seq_stop,
+	.next	= fb_seq_next,
+	.show	= fb_seq_show,
+};
+
+int fb_init_procfs(void)
+{
+	struct proc_dir_entry *proc;
+
+	proc = proc_create_seq("fb", 0, NULL, &fb_proc_seq_ops);
+	if (!proc)
+		return -ENOMEM;
+
+	fb_proc_dir_entry = proc;
+
+	return 0;
+}
+
+void fb_cleanup_procfs(void)
+{
+	proc_remove(fb_proc_dir_entry);
+}

drivers/video/fbdev/core/fbmem.c

@@ -24,9 +24,7 @@
 #include <linux/vt.h>
 #include <linux/init.h>
 #include <linux/linux_logo.h>
-#include <linux/proc_fs.h>
 #include <linux/platform_device.h>
-#include <linux/seq_file.h>
 #include <linux/console.h>
 #include <linux/kmod.h>
 #include <linux/err.h>
@@ -48,8 +46,7 @@
 
 #define FBPIXMAPSIZE	(1024 * 8)
 
-static DEFINE_MUTEX(registration_lock);
-
+DEFINE_MUTEX(registration_lock);
 struct fb_info *registered_fb[FB_MAX] __read_mostly;
 int num_registered_fb __read_mostly;
 #define for_each_registered_fb(i)		\
@@ -705,40 +702,6 @@ int fb_show_logo(struct fb_info *info, int rotate) { return 0; }
 EXPORT_SYMBOL(fb_prepare_logo);
 EXPORT_SYMBOL(fb_show_logo);
 
-static void *fb_seq_start(struct seq_file *m, loff_t *pos)
-{
-	mutex_lock(&registration_lock);
-	return (*pos < FB_MAX) ? pos : NULL;
-}
-
-static void *fb_seq_next(struct seq_file *m, void *v, loff_t *pos)
-{
-	(*pos)++;
-	return (*pos < FB_MAX) ? pos : NULL;
-}
-
-static void fb_seq_stop(struct seq_file *m, void *v)
-{
-	mutex_unlock(&registration_lock);
-}
-
-static int fb_seq_show(struct seq_file *m, void *v)
-{
-	int i = *(loff_t *)v;
-	struct fb_info *fi = registered_fb[i];
-
-	if (fi)
-		seq_printf(m, "%d %s\n", fi->node, fi->fix.id);
-	return 0;
-}
-
-static const struct seq_operations __maybe_unused proc_fb_seq_ops = {
-	.start	= fb_seq_start,
-	.next	= fb_seq_next,
-	.stop	= fb_seq_stop,
-	.show	= fb_seq_show,
-};
-
 /*
  * We hold a reference to the fb_info in file->private_data,
  * but if the current registered fb has changed, we don't
@@ -1624,8 +1587,9 @@ fbmem_init(void)
 {
 	int ret;
 
-	if (!proc_create_seq("fb", 0, NULL, &proc_fb_seq_ops))
-		return -ENOMEM;
+	ret = fb_init_procfs();
+	if (ret)
+		return ret;
 
 	ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
 	if (ret) {
@@ -1648,7 +1612,7 @@ fbmem_init(void)
 err_class:
 	unregister_chrdev(FB_MAJOR, "fb");
 err_chrdev:
-	remove_proc_entry("fb", NULL);
+	fb_cleanup_procfs();
 	return ret;
 }
 
@@ -1659,7 +1623,7 @@ fbmem_exit(void)
 {
 	fb_console_exit();
 
-	remove_proc_entry("fb", NULL);
+	fb_cleanup_procfs();
 	class_destroy(fb_class);
 	unregister_chrdev(FB_MAJOR, "fb");
 }