drivers/serial: call flush_to_ldisc when the irq is threaded

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

2 files changed, 10 insertions, 1 deletions

diff --git a/drivers/char/tty_buffer.c b/drivers/char/tty_buffer.c
index 810ee25d66a4..fdd854206863 100644
--- a/drivers/char/tty_buffer.c
+++ b/drivers/char/tty_buffer.c
@@ -482,10 +482,14 @@ void tty_flip_buffer_push(struct tty_struct *tty)
                 tty->buf.tail->commit = tty->buf.tail->used;
         spin_unlock_irqrestore(&tty->buf.lock, flags);
 
+#ifndef CONFIG_PREEMPT_RT
         if (tty->low_latency)
                 flush_to_ldisc(&tty->buf.work.work);
         else
                 schedule_delayed_work(&tty->buf.work, 1);
+#else
+        flush_to_ldisc(&tty->buf.work.work);
+#endif
 }
 EXPORT_SYMBOL(tty_flip_buffer_push);
 
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);