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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
parenta88d75b257b2b28b26d7d4d2b640f05feb00ad53 (diff)
downloadlinux-stericsson-d8a5a8d7cc32e4474326e0ecc1b959063490efc9.tar.gz
[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>
-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 e001ea0606ec..bbf78aaf9e01 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)