Merge branch 'for-5.7-console-exit' of...

Merge branch 'for-5.7-console-exit' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk into tty-next

We need the console patches in here as well for futher work from Andy.

* 'for-5.7-console-exit' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  console: Introduce ->exit() callback
  console: Don't notify user space when unregister non-listed console
  console: Avoid positive return code from unregister_console()
  console: Drop misleading comment
  console: Use for_each_console() helper in unregister_console()
  console: Drop double check for console_drivers being non-NULL
  console: Don't perform test for CON_BRL flag
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/accessibility/braille/braille_console.c

@@ -347,8 +347,6 @@ int braille_register_console(struct console *console, int index,
 {
 	int ret;
 
-	if (!(console->flags & CON_BRL))
-		return 0;
 	if (!console_options)
 		/* Only support VisioBraille for now */
 		console_options = "57600o8";
@@ -371,8 +369,6 @@ int braille_unregister_console(struct console *console)
 {
 	if (braille_co != console)
 		return -EINVAL;
-	if (!(console->flags & CON_BRL))
-		return 0;
 	unregister_keyboard_notifier(&keyboard_notifier_block);
 	unregister_vt_notifier(&vt_notifier_block);
 	braille_co = NULL;

include/linux/console.h

@@ -148,6 +148,7 @@ struct console {
 	struct tty_driver *(*device)(struct console *, int *);
 	void	(*unblank)(void);
 	int	(*setup)(struct console *, char *);
+	int	(*exit)(struct console *);
 	int	(*match)(struct console *, char *name, int idx, char *options);
 	short	flags;
 	short	index;

kernel/printk/printk.c

@@ -1772,9 +1772,6 @@ static void call_console_drivers(const char *ext_text, size_t ext_len,
 
 	trace_console_rcuidle(text, len);
 
-	if (!console_drivers)
-		return;
-
 	for_each_console(con) {
 		if (exclusive_console && con != exclusive_console)
 			continue;
@@ -2653,19 +2650,17 @@ void register_console(struct console *newcon)
 	struct console_cmdline *c;
 	static bool has_preferred;
 
-	if (console_drivers)
-		for_each_console(bcon)
-			if (WARN(bcon == newcon,
-					"console '%s%d' already registered\n",
+	for_each_console(bcon) {
+		if (WARN(bcon == newcon, "console '%s%d' already registered\n",
 					 bcon->name, bcon->index))
 			return;
+	}
 
 	/*
 	 * before we register a new CON_BOOT console, make sure we don't
 	 * already have a valid console
 	 */
-	if (console_drivers && newcon->flags & CON_BOOT) {
-		/* find the last or real console */
+	if (newcon->flags & CON_BOOT) {
 		for_each_console(bcon) {
 			if (!(bcon->flags & CON_BOOT)) {
 				pr_info("Too late to register bootconsole %s%d\n",
@@ -2813,7 +2808,7 @@ EXPORT_SYMBOL(register_console);
 
 int unregister_console(struct console *console)
 {
-        struct console *a, *b;
+	struct console *con;
 	int res;
 
 	pr_info("%sconsole [%s%d] disabled\n",
@@ -2821,26 +2816,30 @@ int unregister_console(struct console *console)
 		console->name, console->index);
 
 	res = _braille_unregister_console(console);
-	if (res)
+	if (res < 0)
 		return res;
+	if (res > 0)
+		return 0;
 
-	res = 1;
+	res = -ENODEV;
 	console_lock();
 	if (console_drivers == console) {
 		console_drivers=console->next;
 		res = 0;
-	} else if (console_drivers) {
-		for (a=console_drivers->next, b=console_drivers ;
-		     a; b=a, a=b->next) {
-			if (a == console) {
-				b->next = a->next;
+	} else {
+		for_each_console(con) {
+			if (con->next == console) {
+				con->next = console->next;
 				res = 0;
 				break;
 			}
 		}
 	}
 
-	if (!res && (console->flags & CON_EXTENDED))
+	if (res)
+		goto out_disable_unlock;
+
+	if (console->flags & CON_EXTENDED)
 		nr_ext_console_drivers--;
 
 	/*
@@ -2853,6 +2852,16 @@ int unregister_console(struct console *console)
 	console->flags &= ~CON_ENABLED;
 	console_unlock();
 	console_sysfs_notify();
+
+	if (console->exit)
+		res = console->exit(console);
+
+	return res;
+
+out_disable_unlock:
+	console->flags &= ~CON_ENABLED;
+	console_unlock();
+
 	return res;
 }
 EXPORT_SYMBOL(unregister_console);