drivers-serial-Clean-up-the-locking-for-rt.patch

From 6d60c75c339e44f48c2e88d4aa3d8c1aafdb24be Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 3 Jul 2009 08:30:01 -0500
Subject: [PATCH] drivers/serial: Clean up the locking for -rt

commit 295048108ae1c03ede2297c08133526c5a1b6b3b in tip.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index e9b15c3..e348e3c 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2735,14 +2735,10 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count)
 
 	touch_nmi_watchdog();
 
-	local_irq_save(flags);
-	if (up->port.sysrq) {
-		/* serial8250_handle_port() already took the lock */
-		locked = 0;
-	} else if (oops_in_progress) {
-		locked = spin_trylock(&up->port.lock);
-	} else
-		spin_lock(&up->port.lock);
+	if (up->port.sysrq || oops_in_progress)
+		locked = spin_trylock_irqsave(&up->port.lock, flags);
+	else
+		spin_lock_irqsave(&up->port.lock, flags);
 
 	/*
 	 *	First save the IER then disable the interrupts
@@ -2774,8 +2770,7 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count)
 		check_modem_status(up);
 
 	if (locked)
-		spin_unlock(&up->port.lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&up->port.lock, flags);
 }
 
 static int __init serial8250_console_setup(struct console *co, char *options)
-- 
1.7.1.1