diff options
Diffstat (limited to 'drivers/tty/n_tty.c')
| -rw-r--r-- | drivers/tty/n_tty.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 54da8f49394d..85e46422311c 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1946,6 +1946,18 @@ static inline int input_available_p(struct tty_struct *tty, int poll) return ldata->commit_head - ldata->read_tail >= amt; } +static inline int check_other_done(struct tty_struct *tty) +{ + int done = test_bit(TTY_OTHER_DONE, &tty->flags); + if (done) { + /* paired with cmpxchg() in check_other_closed(); ensures + * read buffer head index is not stale + */ + smp_mb__after_atomic(); + } + return done; +} + /** * copy_from_read_buf - copy read data directly * @tty: terminal device @@ -2164,7 +2176,7 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, struct n_tty_data *ldata = tty->disc_data; unsigned char __user *b = buf; DEFINE_WAIT_FUNC(wait, woken_wake_function); - int c; + int c, done; int minimum, time; ssize_t retval = 0; long timeout; @@ -2232,8 +2244,10 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, ((minimum - (b - buf)) >= 1)) ldata->minimum_to_wake = (minimum - (b - buf)); + done = check_other_done(tty); + if (!input_available_p(tty, 0)) { - if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { + if (done) { retval = -EIO; break; } @@ -2440,12 +2454,12 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, poll_wait(file, &tty->read_wait, wait); poll_wait(file, &tty->write_wait, wait); + if (check_other_done(tty)) + mask |= POLLHUP; if (input_available_p(tty, 1)) mask |= POLLIN | POLLRDNORM; if (tty->packet && tty->link->ctrl_status) mask |= POLLPRI | POLLIN | POLLRDNORM; - if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) - mask |= POLLHUP; if (tty_hung_up_p(file)) mask |= POLLHUP; if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { |