Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso...

[firefly-linux-kernel-4.4.55.git] / drivers / tty / n_tty.c

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 01bf5eb4f2384a66999157ddd855162c8e966f7a..7a744b69c3d144516388d3e8a4bc2fc440fd4d34 100644 (file)
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2183,28 +2183,34 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 
                if (!input_available_p(tty, 0)) {
                        if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
-                               retval = -EIO;
-                               break;
-                       }
-                       if (tty_hung_up_p(file))
-                               break;
-                       if (!timeout)
-                               break;
-                       if (file->f_flags & O_NONBLOCK) {
-                               retval = -EAGAIN;
-                               break;
-                       }
-                       if (signal_pending(current)) {
-                               retval = -ERESTARTSYS;
-                               break;
-                       }
-                       n_tty_set_room(tty);
-                       up_read(&tty->termios_rwsem);
+                               up_read(&tty->termios_rwsem);
+                               tty_flush_to_ldisc(tty);
+                               down_read(&tty->termios_rwsem);
+                               if (!input_available_p(tty, 0)) {
+                                       retval = -EIO;
+                                       break;
+                               }
+                       } else {
+                               if (tty_hung_up_p(file))
+                                       break;
+                               if (!timeout)
+                                       break;
+                               if (file->f_flags & O_NONBLOCK) {
+                                       retval = -EAGAIN;
+                                       break;
+                               }
+                               if (signal_pending(current)) {
+                                       retval = -ERESTARTSYS;
+                                       break;
+                               }
+                               n_tty_set_room(tty);
+                               up_read(&tty->termios_rwsem);
 
-                       timeout = schedule_timeout(timeout);
+                               timeout = schedule_timeout(timeout);
 
-                       down_read(&tty->termios_rwsem);
-                       continue;
+                               down_read(&tty->termios_rwsem);
+                               continue;
+                       }
                }
                __set_current_state(TASK_RUNNING);