X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=drivers%2Ftty%2Fn_tty.c;h=7a744b69c3d144516388d3e8a4bc2fc440fd4d34;hb=026f8f612a137324869b6dbdf1d526d176e1766e;hp=c9a9ddd1d0bc2aa5091d7e1678920df2d9292429;hpb=0fbf2cc983ca15208545010863c6536d36a25f3a;p=firefly-linux-kernel-4.4.55.git

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);