1 files changed, 27 insertions, 22 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index c9a9ddd1d0bc..7a744b69c3d1 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1758,8 +1758,7 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
                 canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON;
         if (canon_change) {
                 bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
-                ldata->line_start = 0;
-                ldata->canon_head = ldata->read_tail;
+                ldata->line_start = ldata->canon_head = ldata->read_tail;
                 ldata->erasing = 0;
                 ldata->lnext = 0;
         }
@@ -2184,28 +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);