[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>
This commit is contained in:
Russell King 2006-05-02 16:04:29 +01:00 committed by Russell King
parent a88d75b257
commit d8a5a8d7cc

View File

@ -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)