drivers/serial: call flush_to_ldisc when the irq is threaded

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index a1f403ec9213..d4d69e155afe 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1595,7 +1595,12 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
 
                 l = l->next;
 
-                if (l == i->head && pass_counter++ > PASS_LIMIT) {
+                /*
+                 * On preempt-rt we can be preempted and run in our
+                 * own thread.
+                 */
+                if (!preempt_rt() && l == i->head &&
+                    pass_counter++ > PASS_LIMIT) {
                         /* If we hit this, we're dead. */
                         printk(KERN_ERR "serial8250: too much work for "
                                 "irq%d\n", irq);