diff options
Diffstat (limited to 'drivers/tty/n_tty.c')
| -rw-r--r-- | drivers/tty/n_tty.c | 72 |
1 files changed, 45 insertions, 27 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 4bf0fc0843d7..eddeb7889e62 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -79,6 +79,9 @@ struct n_tty_data { unsigned long overrun_time; int num_overrun; + /* non-atomic */ + bool no_room; + unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; unsigned char echo_overrun:1; @@ -114,25 +117,10 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x, return put_user(x, ptr); } -/** - * n_tty_set_room - receive space - * @tty: terminal - * - * Updates tty->receive_room to reflect the currently available space - * in the input buffer, and re-schedules the flip buffer work if space - * just became available. - * - * Locks: Concurrent update is protected with read_lock - */ - -static int set_room(struct tty_struct *tty) +static int receive_room(struct tty_struct *tty) { struct n_tty_data *ldata = tty->disc_data; int left; - int old_left; - unsigned long flags; - - raw_spin_lock_irqsave(&ldata->read_lock, flags); if (I_PARMRK(tty)) { /* Multiply read_cnt by 3, since each byte might take up to @@ -150,18 +138,27 @@ static int set_room(struct tty_struct *tty) */ if (left <= 0) left = ldata->icanon && !ldata->canon_data; - old_left = tty->receive_room; - tty->receive_room = left; - raw_spin_unlock_irqrestore(&ldata->read_lock, flags); - - return left && !old_left; + return left; } +/** + * n_tty_set_room - receive space + * @tty: terminal + * + * Re-schedules the flip buffer work if space just became available. + * + * Locks: Concurrent update is protected with read_lock + */ + static void n_tty_set_room(struct tty_struct *tty) { + struct n_tty_data *ldata = tty->disc_data; + /* Did this open up the receive buffer? We may need to flip */ - if (set_room(tty)) { + if (unlikely(ldata->no_room) && receive_room(tty)) { + ldata->no_room = 0; + WARN_RATELIMIT(tty->port->itty == NULL, "scheduling with invalid itty\n"); /* see if ldisc has been killed - if so, this means that @@ -1408,8 +1405,8 @@ static void n_tty_write_wakeup(struct tty_struct *tty) * calls one at a time and in order (or using flush_to_ldisc) */ -static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, - char *fp, int count) +static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) { struct n_tty_data *ldata = tty->disc_data; const unsigned char *p; @@ -1464,8 +1461,6 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, tty->ops->flush_chars(tty); } - set_room(tty); - if ((!ldata->icanon && (ldata->read_cnt >= ldata->minimum_to_wake)) || L_EXTPROC(tty)) { kill_fasync(&tty->fasync, SIGIO, POLL_IN); @@ -1480,7 +1475,7 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, */ while (1) { tty_set_flow_change(tty, TTY_THROTTLE_SAFE); - if (tty->receive_room >= TTY_THRESHOLD_THROTTLE) + if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) break; if (!tty_throttle_safe(tty)) break; @@ -1488,6 +1483,28 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, __tty_set_flow_change(tty, 0); } +static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + __receive_buf(tty, cp, fp, count); +} + +static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + struct n_tty_data *ldata = tty->disc_data; + int room; + + tty->receive_room = room = receive_room(tty); + if (!room) + ldata->no_room = 1; + count = min(count, room); + if (count) + __receive_buf(tty, cp, fp, count); + + return count; +} + int is_ignored(int sig) { return (sigismember(¤t->blocked, sig) || @@ -2203,6 +2220,7 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = { .receive_buf = n_tty_receive_buf, .write_wakeup = n_tty_write_wakeup, .fasync = n_tty_fasync, + .receive_buf2 = n_tty_receive_buf2, }; /** |