linux-kernel - [PATCH 2/2] tty: sysrq: Use printk_loud_console context on __handle

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Message-Id: <20241016-printk-loud-con-v1-2-065e4dad6632@suse.com>
Date: Wed, 16 Oct 2024 14:03:02 -0300
From: Marcos Paulo de Souza <mpdesouza@...e.com>
To: Petr Mladek <pmladek@...e.com>, Steven Rostedt <rostedt@...dmis.org>, 
 John Ogness <john.ogness@...utronix.de>, 
 Sergey Senozhatsky <senozhatsky@...omium.org>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 Jiri Slaby <jirislaby@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org, 
 Marcos Paulo de Souza <mpdesouza@...e.com>
Subject: [PATCH 2/2] tty: sysrq: Use printk_loud_console context on
 __handle_sysrq

By using the printk_loud_console the loglevel workaround can be removed.
The workaround existed to always send the sysrq header message to all
consoles not matter what was the current loglevel.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@...e.com>
---
 drivers/tty/sysrq.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 930b04e3d148..1ff11cf6275a 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -583,7 +583,6 @@ static void __sysrq_put_key_op(u8 key, const struct sysrq_key_op *op_p)
 void __handle_sysrq(u8 key, bool check_mask)
 {
 	const struct sysrq_key_op *op_p;
-	int orig_log_level;
 	int orig_suppress_printk;
 	int i;
 
@@ -593,13 +592,12 @@ void __handle_sysrq(u8 key, bool check_mask)
 	rcu_sysrq_start();
 	rcu_read_lock();
 	/*
-	 * Raise the apparent loglevel to maximum so that the sysrq header
-	 * is shown to provide the user with positive feedback.  We do not
-	 * simply emit this at KERN_EMERG as that would change message
-	 * routing in the consumers of /proc/kmsg.
+	 * Enter in the console_loud context so that sysrq header is shown to
+	 * provide the user with positive feedback.  We do not simply emit this
+	 * at KERN_EMERG as that would change message routing in the consumers
+	 * of /proc/kmsg.
 	 */
-	orig_log_level = console_loglevel;
-	console_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
+	printk_loud_console_enter();
 
 	op_p = __sysrq_get_key_op(key);
 	if (op_p) {
@@ -609,11 +607,11 @@ void __handle_sysrq(u8 key, bool check_mask)
 		 */
 		if (!check_mask || sysrq_on_mask(op_p->enable_mask)) {
 			pr_info("%s\n", op_p->action_msg);
-			console_loglevel = orig_log_level;
+			printk_loud_console_exit();
 			op_p->handler(key);
 		} else {
 			pr_info("This sysrq operation is disabled.\n");
-			console_loglevel = orig_log_level;
+			printk_loud_console_exit();
 		}
 	} else {
 		pr_info("HELP : ");
@@ -631,7 +629,7 @@ void __handle_sysrq(u8 key, bool check_mask)
 			}
 		}
 		pr_cont("\n");
-		console_loglevel = orig_log_level;
+		printk_loud_console_exit();
 	}
 	rcu_read_unlock();
 	rcu_sysrq_end();

-- 
2.46.1