From d8a5a8d7cc32e4474326e0ecc1b959063490efc9 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 2 May 2006 16:04:29 +0100 Subject: [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 --- drivers/serial/8250.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers/serial') 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) -- cgit v1.2.3