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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2006-05-02 16:04:29 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-05-02 16:04:29 +0100
commitd8a5a8d7cc32e4474326e0ecc1b959063490efc9 (patch)
treeb174cda624301fde6e020e346b60b5e8e31f6283 /drivers/serial/8250.c
parenta88d75b257b2b28b26d7d4d2b640f05feb00ad53 (diff)
[SERIAL] 8250: add locking to console write function
x86 SMP breaks as a result of the previous change, we have no real option other than to add locking to the 8250 console write function. If an oops is in progress, try to acquire the lock. If we fail to do so, continue anyway. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers/serial/8250.c')
-rw-r--r--drivers/serial/8250.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index e001ea0606e..bbf78aaf9e0 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2235,10 +2235,17 @@ static void
serial8250_console_write(struct console *co, const char *s, unsigned int count)
{
struct uart_8250_port *up = &serial8250_ports[co->index];
+ unsigned long flags;
unsigned int ier;
+ int locked = 1;
touch_nmi_watchdog();
+ if (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
*/
@@ -2257,6 +2264,9 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count)
*/
wait_for_xmitr(up, BOTH_EMPTY);
serial_out(up, UART_IER, ier);
+
+ if (locked)
+ spin_unlock_irqrestore(&up->port.lock, flags);
}
static int serial8250_console_setup(struct console *co, char *options)