Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / drivers / tty / n_tty.c

diff --git a/kernel/drivers/tty/n_tty.c b/kernel/drivers/tty/n_tty.c
index cf000b3..84e71bd 100644 (file)
--- a/kernel/drivers/tty/n_tty.c
+++ b/kernel/drivers/tty/n_tty.c
@@ -1955,18 +1955,6 @@ 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
@@ -2171,7 +2159,7 @@ 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, done;
+       int c;
        int minimum, time;
        ssize_t retval = 0;
        long timeout;
@@ -2239,32 +2227,35 @@ 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 (done) {
-                               retval = -EIO;
-                               break;
-                       }
-                       if (tty_hung_up_p(file))
-                               break;
-                       if (!timeout)
-                               break;
-                       if (file->f_flags & O_NONBLOCK) {
-                               retval = -EAGAIN;
-                               break;
-                       }
-                       if (signal_pending(current)) {
-                               retval = -ERESTARTSYS;
-                               break;
-                       }
                        up_read(&tty->termios_rwsem);
+                       tty_buffer_flush_work(tty->port);
+                       down_read(&tty->termios_rwsem);
+                       if (!input_available_p(tty, 0)) {
+                               if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
+                                       retval = -EIO;
+                                       break;
+                               }
+                               if (tty_hung_up_p(file))
+                                       break;
+                               if (!timeout)
+                                       break;
+                               if (file->f_flags & O_NONBLOCK) {
+                                       retval = -EAGAIN;
+                                       break;
+                               }
+                               if (signal_pending(current)) {
+                                       retval = -ERESTARTSYS;
+                                       break;
+                               }
+                               up_read(&tty->termios_rwsem);
 
-                       timeout = wait_woken(&wait, TASK_INTERRUPTIBLE,
-                                            timeout);
+                               timeout = wait_woken(&wait, TASK_INTERRUPTIBLE,
+                                               timeout);
 
-                       down_read(&tty->termios_rwsem);
-                       continue;
+                               down_read(&tty->termios_rwsem);
+                               continue;
+                       }
                }
 
                if (ldata->icanon && !L_EXTPROC(tty)) {
@@ -2446,12 +2437,17 @@ 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;
+       else {
+               tty_buffer_flush_work(tty->port);
+               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))) {