1 files changed, 14 insertions, 3 deletions

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index bdae8327143c..428f4fe0b5f7 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -1102,6 +1102,11 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
         if (I_IUCLC(tty) && L_IEXTEN(tty))
                 c = tolower(c);
 
+        if (L_EXTPROC(tty)) {
+                put_tty_queue(c, tty);
+                return;
+        }
+
         if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
             I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) &&
             c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) {
@@ -1409,7 +1414,8 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 
         n_tty_set_room(tty);
 
-        if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
+        if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) ||
+                L_EXTPROC(tty)) {
                 kill_fasync(&tty->fasync, SIGIO, POLL_IN);
                 if (waitqueue_active(&tty->read_wait))
                         wake_up_interruptible(&tty->read_wait);
@@ -1585,7 +1591,7 @@ static int n_tty_open(struct tty_struct *tty)
 static inline int input_available_p(struct tty_struct *tty, int amt)
 {
         tty_flush_to_ldisc(tty);
-        if (tty->icanon) {
+        if (tty->icanon && !L_EXTPROC(tty)) {
                 if (tty->canon_data)
                         return 1;
         } else if (tty->read_cnt >= (amt ? amt : 1))
@@ -1632,6 +1638,11 @@ static int copy_from_read_buf(struct tty_struct *tty,
                 spin_lock_irqsave(&tty->read_lock, flags);
                 tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
                 tty->read_cnt -= n;
+                /* Turn single EOF into zero-length read */
+                if (L_EXTPROC(tty) && tty->icanon && n == 1) {
+                        if (!tty->read_cnt && (*b)[n-1] == EOF_CHAR(tty))
+                                n--;
+                }
                 spin_unlock_irqrestore(&tty->read_lock, flags);
                 *b += n;
                 *nr -= n;
@@ -1812,7 +1823,7 @@ do_it_again:
                         nr--;
                 }
 
-                if (tty->icanon) {
+                if (tty->icanon && !L_EXTPROC(tty)) {
                         /* N.B. avoid overrun if nr == 0 */
                         while (nr && tty->read_cnt) {
                                 int eol;