[SERIAL]: Fix console write locking in sparc drivers.

Mirror the logic in 8250 for proper console write locking
when SYSRQ is triggered or an OOPS is in progress.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 3 deletions

diff --git a/drivers/serial/sunzilog.c b/drivers/serial/sunzilog.c
index 15b6e1cb040b..0a3e10a4a35d 100644
--- a/drivers/serial/sunzilog.c
+++ b/drivers/serial/sunzilog.c
@@ -9,7 +9,7 @@
  * C. Dost, Pete Zaitcev, Ted Ts'o and Alex Buell for their
  * work there.
  *
- *  Copyright (C) 2002, 2006 David S. Miller (davem@davemloft.net)
+ * Copyright (C) 2002, 2006, 2007 David S. Miller (davem@davemloft.net)
  */
 
 #include <linux/module.h>
@@ -1151,11 +1151,22 @@ sunzilog_console_write(struct console *con, const char *s, unsigned int count)
 {
         struct uart_sunzilog_port *up = &sunzilog_port_table[con->index];
         unsigned long flags;
+        int locked = 1;
+
+        local_irq_save(flags);
+        if (up->port.sysrq) {
+                locked = 0;
+        } else if (oops_in_progress) {
+                locked = spin_trylock(&up->port.lock);
+        } else
+                spin_lock(&up->port.lock);
 
-        spin_lock_irqsave(&up->port.lock, flags);
         uart_console_write(&up->port, s, count, sunzilog_putchar);
         udelay(2);
-        spin_unlock_irqrestore(&up->port.lock, flags);
+
+        if (locked)
+                spin_unlock(&up->port.lock);
+        local_irq_restore(flags);
 }
 
 static int __init sunzilog_console_setup(struct console *con, char *options)