[PATCH v4 05/11] printk: Cleanup _braille_(un)register_console() wrappers

[Petr Mladek <pmladek@suse.com>]

The _braille_(un)register_console() wrappers currently attempt to hide
implementation details like the CON_BRL flag and pc->brl_options. This
forces callers to handle an unconventional tri-state return value (0 for
NOP, >0 for success, <0 for error), which makes the control flow harder
to follow and non-standard.

Refactor the wrappers to use standard kernel return codes (0 for success,
-ERRCODE on failure). Move the responsibility of checking brl_options
to the caller to make the logic more explicit.

Additionally, move the assignment of the CON_BRL flag from the internal
wrapper to braille_register_console(). This aligns it with how
CON_ENABLED is handled. To maintain symmetry and fix a potential bug
where flags might persist after removal, explicitly clear both
CON_ENABLED and CON_BRL in braille_unregister_console().

No behavior change.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
---
 drivers/accessibility/braille/braille_console.c |  7 ++++---
 kernel/printk/braille.c                         | 16 +++-------------
 kernel/printk/braille.h                         | 12 ++++++++++++
 kernel/printk/printk.c                          | 13 +++++--------
 4 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/drivers/accessibility/braille/braille_console.c b/drivers/accessibility/braille/braille_console.c
index 06b43b678d6e..7b324329882f 100644
--- a/drivers/accessibility/braille/braille_console.c
+++ b/drivers/accessibility/braille/braille_console.c
@@ -360,12 +360,12 @@ int braille_register_console(struct console *console, int index,
 		if (ret != 0)
 			return ret;
 	}
-	console->flags |= CON_ENABLED;
+	console->flags |= CON_ENABLED | CON_BRL;
 	console->index = index;
 	braille_co = console;
 	register_keyboard_notifier(&keyboard_notifier_block);
 	register_vt_notifier(&vt_notifier_block);
-	return 1;
+	return 0;
 }
 
 int braille_unregister_console(struct console *console)
@@ -375,5 +375,6 @@ int braille_unregister_console(struct console *console)
 	unregister_keyboard_notifier(&keyboard_notifier_block);
 	unregister_vt_notifier(&vt_notifier_block);
 	braille_co = NULL;
-	return 1;
+	console->flags &= ~(CON_ENABLED | CON_BRL);
+	return 0;
 }
diff --git a/kernel/printk/braille.c b/kernel/printk/braille.c
index 9d21a2bb1d38..593f83eb0487 100644
--- a/kernel/printk/braille.c
+++ b/kernel/printk/braille.c
@@ -37,22 +37,12 @@ int _braille_console_setup(char **str, char **brl_options)
 int
 _braille_register_console(struct console *console, struct preferred_console *pc)
 {
-	int rtn = 0;
-
-	if (pc->brl_options) {
-		console->flags |= CON_BRL;
-		rtn = braille_register_console(console, pc->index, pc->options,
-					       pc->brl_options);
-	}
-
-	return rtn;
+	return braille_register_console(console, pc->index, pc->options,
+					pc->brl_options);
 }
 
 int
 _braille_unregister_console(struct console *console)
 {
-	if (console->flags & CON_BRL)
-		return braille_unregister_console(console);
-
-	return 0;
+	return braille_unregister_console(console);
 }
diff --git a/kernel/printk/braille.h b/kernel/printk/braille.h
index 0bdac303f8b1..ec5feac1f508 100644
--- a/kernel/printk/braille.h
+++ b/kernel/printk/braille.h
@@ -11,6 +11,12 @@ braille_update_options(struct preferred_console *pc, char *brl_options)
 		pc->brl_options = brl_options;
 }
 
+static inline bool
+is_braille_console_preferred(struct preferred_console *pc)
+{
+	return (!!pc->brl_options);
+}
+
 /*
  * Setup console according to braille options.
  * Return -EINVAL on syntax error, 0 on success (or no braille option was
@@ -34,6 +40,12 @@ braille_update_options(struct preferred_console *pc, char *brl_options)
 {
 }
 
+static inline bool
+is_braille_console_preferred(struct preferred_console *pc)
+{
+	return false;
+}
+
 static inline int
 _braille_console_setup(char **str, char **brl_options)
 {
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index b7dbbc1baeb1..4ee98a4d2ce5 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -4003,8 +4003,8 @@ static int try_enable_preferred_console(struct console *newcon,
 			if (newcon->index < 0)
 				newcon->index = pc->index;
 
-			if (_braille_register_console(newcon, pc))
-				return 0;
+			if (is_braille_console_preferred(pc))
+				return _braille_register_console(newcon, pc);
 
 			err = console_call_setup(newcon, pc->options);
 			if (err)
@@ -4316,17 +4316,14 @@ static int unregister_console_locked(struct console *console)
 	bool found_boot_con = false;
 	unsigned long flags;
 	struct console *c;
-	int res;
+	int res = 0;
 
 	lockdep_assert_console_list_lock_held();
 
 	con_printk(KERN_INFO, console, "disabled\n");
 
-	res = _braille_unregister_console(console);
-	if (res < 0)
-		return res;
-	if (res > 0)
-		return 0;
+	if (console->flags & CON_BRL)
+		return _braille_unregister_console(console);
 
 	if (!console_is_registered_locked(console))
 		res = -ENODEV;
-- 
2.54.0