1 files changed, 8 insertions, 7 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index d15624c1b751..fe9d129c8735 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1900,13 +1900,10 @@ static inline int input_available_p(struct tty_struct *tty, int poll)
 	struct n_tty_data *ldata = tty->disc_data;
 	int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1;
 
-	if (ldata->icanon && !L_EXTPROC(tty)) {
-		if (ldata->canon_head != ldata->read_tail)
-			return 1;
-	} else if (read_cnt(ldata) >= amt)
-		return 1;
-
-	return 0;
+	if (ldata->icanon && !L_EXTPROC(tty))
+		return ldata->canon_head != ldata->read_tail;
+	else
+		return read_cnt(ldata) >= amt;
 }
 
 /**
@@ -2356,8 +2353,12 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 			if (tty->ops->flush_chars)
 				tty->ops->flush_chars(tty);
 		} else {
+			struct n_tty_data *ldata = tty->disc_data;
+
 			while (nr > 0) {
+				mutex_lock(&ldata->output_lock);
 				c = tty->ops->write(tty, b, nr);
+				mutex_unlock(&ldata->output_lock);
 				if (c < 0) {
 					retval = c;
 					goto break_out;