diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index 2e50f4d..ace0c19 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -1813,13 +1813,13 @@ do_it_again:
 
 		if (tty->icanon) {
 			/* N.B. avoid overrun if nr == 0 */
+			spin_lock_irqsave(&tty->read_lock, flags);
 			while (nr && tty->read_cnt) {
 				int eol;
 
 				eol = test_and_clear_bit(tty->read_tail,
 						tty->read_flags);
 				c = tty->read_buf[tty->read_tail];
-				spin_lock_irqsave(&tty->read_lock, flags);
 				tty->read_tail = ((tty->read_tail+1) &
 						  (N_TTY_BUF_SIZE-1));
 				tty->read_cnt--;
@@ -1831,7 +1831,6 @@ do_it_again:
 					if (--tty->canon_data < 0)
 						tty->canon_data = 0;
 				}
-				spin_unlock_irqrestore(&tty->read_lock, flags);
 
 				if (!eol || (c != __DISABLED_CHAR)) {
 					if (tty_put_user(tty, c, b++)) {
@@ -1846,6 +1845,7 @@ do_it_again:
 					break;
 				}
 			}
+			spin_unlock_irqrestore(&tty->read_lock, flags);
 			if (retval)
 				break;
 		} else {