[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, 0 deletions

diff --git a/drivers/serial/sunsu.c b/drivers/serial/sunsu.c
index 2a63cdba3208..26d720baf88c 100644
--- a/drivers/serial/sunsu.c
+++ b/drivers/serial/sunsu.c
@@ -1288,7 +1288,17 @@ static void sunsu_console_write(struct console *co, const char *s,
                                 unsigned int count)
 {
         struct uart_sunsu_port *up = &sunsu_ports[co->index];
+        unsigned long flags;
         unsigned int ier;
+        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);
 
         /*
          *      First save the UER then disable the interrupts
@@ -1304,6 +1314,10 @@ static void sunsu_console_write(struct console *co, const char *s,
          */
         wait_for_xmitr(up);
         serial_out(up, UART_IER, ier);
+
+        if (locked)
+                spin_unlock(&up->port.lock);
+        local_irq_restore(flags);
 }
 
 /*