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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Thu, 14 Feb 2019 17:38:24 +0100
Subject: [PATCH] serial: 8250: remove that trylock in
serial8250_console_write_atomic()
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patches-5.4.3-rt1.tar.xz
This does not work as rtmutex in NMI context. As per John, it is not
needed.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
drivers/tty/serial/8250/8250_port.c | 11 -----------
1 file changed, 11 deletions(-)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -3187,17 +3187,9 @@ void serial8250_console_write_atomic(str
{
struct uart_port *port = &up->port;
unsigned int flags;
- bool locked;
console_atomic_lock(&flags);
- /*
- * If possible, keep any other CPUs from working with the
- * UART until the atomic message is completed. This helps
- * to keep the output more orderly.
- */
- locked = spin_trylock(&port->lock);
-
touch_nmi_watchdog();
clear_ier(up);
@@ -3212,9 +3204,6 @@ void serial8250_console_write_atomic(str
wait_for_xmitr(up, BOTH_EMPTY);
restore_ier(up);
- if (locked)
- spin_unlock(&port->lock);
-
console_atomic_unlock(flags);
}
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