[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, 26 insertions, 4 deletions

diff --git a/drivers/serial/sunhv.c b/drivers/serial/sunhv.c
index 96557e6dba60..17bcca53d6a1 100644
--- a/drivers/serial/sunhv.c
+++ b/drivers/serial/sunhv.c
@@ -440,8 +440,16 @@ static void sunhv_console_write_paged(struct console *con, const char *s, unsign
 {
         struct uart_port *port = sunhv_port;
         unsigned long flags;
+        int locked = 1;
+
+        local_irq_save(flags);
+        if (port->sysrq) {
+                locked = 0;
+        } else if (oops_in_progress) {
+                locked = spin_trylock(&port->lock);
+        } else
+                spin_lock(&port->lock);
 
-        spin_lock_irqsave(&port->lock, flags);
         while (n > 0) {
                 unsigned long ra = __pa(con_write_page);
                 unsigned long page_bytes;
@@ -469,7 +477,10 @@ static void sunhv_console_write_paged(struct console *con, const char *s, unsign
                         ra += written;
                 }
         }
-        spin_unlock_irqrestore(&port->lock, flags);
+
+        if (locked)
+                spin_unlock(&port->lock);
+        local_irq_restore(flags);
 }
 
 static inline void sunhv_console_putchar(struct uart_port *port, char c)
@@ -488,7 +499,15 @@ static void sunhv_console_write_bychar(struct console *con, const char *s, unsig
 {
         struct uart_port *port = sunhv_port;
         unsigned long flags;
-        int i;
+        int i, locked = 1;
+
+        local_irq_save(flags);
+        if (port->sysrq) {
+                locked = 0;
+        } else if (oops_in_progress) {
+                locked = spin_trylock(&port->lock);
+        } else
+                spin_lock(&port->lock);
 
         spin_lock_irqsave(&port->lock, flags);
         for (i = 0; i < n; i++) {
@@ -496,7 +515,10 @@ static void sunhv_console_write_bychar(struct console *con, const char *s, unsig
                         sunhv_console_putchar(port, '\r');
                 sunhv_console_putchar(port, *s++);
         }
-        spin_unlock_irqrestore(&port->lock, flags);
+
+        if (locked)
+                spin_unlock(&port->lock);
+        local_irq_restore(flags);
 }
 
 static struct console sunhv_console = {