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Message-ID: <20260206165002.496724-5-pmladek@suse.com>
Date: Fri, 6 Feb 2026 17:49:58 +0100
From: Petr Mladek <pmladek@...e.com>
To: John Ogness <john.ogness@...utronix.de>
Cc: Sergey Senozhatsky <senozhatsky@...omium.org>,
Steven Rostedt <rostedt@...dmis.org>,
Marcos Paulo de Souza <mpdesouza@...e.com>,
Chris Down <chris@...isdown.name>,
linux-kernel@...r.kernel.org,
Petr Mladek <pmladek@...e.com>
Subject: [PATCH 4/8] printk: Cleanup _braille_(un)register_console() wrappers
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().
Signed-off-by: Petr Mladek <pmladek@...e.com>
---
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 ee57c7ac9d02..4b2865831a62 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3926,8 +3926,8 @@ 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)
@@ -4239,17 +4239,14 @@ 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;
--
2.52.0
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