Re: 2.6.18-rt1

Ingo Molnar
2006-09-21T19:11:22Z

* Daniel Walker <dwalker@mvista.com> wrote:

> On Wed, 2006-09-20 at 22:14 +0200, Ingo Molnar wrote:
> > > if (up->port.sysrq) {
> > > /* serial8250_handle_port() already took the lock */
> > > locked = 0;
>
>
> In this case it had interrupts off in the !PREEMPT_RT case, but your
> change leaves them on here.. _irqsave only runs in two of the three
> cases..

doh, right you are. I updated to the patch below.

Ingo

Index: linux/drivers/serial/8250.c
===================================================================
--- linux.orig/drivers/serial/8250.c
+++ linux/drivers/serial/8250.c
@@ -2252,14 +2252,10 @@ serial8250_console_write(struct console

touch_nmi_watchdog();

- local_irq_save(flags);
- if (up->port.sysrq) {
- /* serial8250_handle_port() already took the lock */
- locked = 0;
- } else if (oops_in_progress) {
- locked = spin_trylock(&up->port.lock);
- } else
- spin_lock(&up->port.lock);
+ if (up->port.sysrq || 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
@@ -2281,8 +2277,7 @@ serial8250_console_write(struct console
serial_out(up, UART_IER, ier);

if (locked)
- spin_unlock(&up->port.lock);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&up->port.lock, flags);
}

static int serial8250_console_setup(struct console *co, char *options)