linux-kernel - [PATCH printk v4 03/17] printk: Flush console on unregister

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Message-Id: <20240827044333.88596-4-john.ogness@linutronix.de>
Date: Tue, 27 Aug 2024 06:49:19 +0206
From: John Ogness <john.ogness@...utronix.de>
To: Petr Mladek <pmladek@...e.com>
Cc: Sergey Senozhatsky <senozhatsky@...omium.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org
Subject: [PATCH printk v4 03/17] printk: Flush console on unregister_console()

Ensure consoles have flushed pending records before
unregistering. The console should print up to at least its
related "console disabled" record.

Signed-off-by: John Ogness <john.ogness@...utronix.de>
Reviewed-by: Petr Mladek <pmladek@...e.com>
---
 kernel/printk/printk.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index acf668001096..c79e962b822a 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3771,11 +3771,16 @@ static int unregister_console_locked(struct console *console)
 	if (res > 0)
 		return 0;
 
+	if (!console_is_registered_locked(console))
+		res = -ENODEV;
+	else if (console_is_usable(console, console->flags))
+		__pr_flush(console, 1000, true);
+
 	/* Disable it unconditionally */
 	console_srcu_write_flags(console, console->flags & ~CON_ENABLED);
 
-	if (!console_is_registered_locked(console))
-		return -ENODEV;
+	if (res < 0)
+		return res;
 
 	/*
 	 * Use the driver synchronization to ensure that the hardware is not
-- 
2.39.2