diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2014-11-05 20:13:05 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-06 05:50:42 +0300 |
| commit | 52bce7f8d4fc633c9a9d0646eef58ba6ae9a3b73 (patch) | |
| tree | 8d6586f5e62fcd0dbb4c54a64fe687939c79d1b6 /drivers/tty/pty.c | |
| parent | 1bb954153aa97702db4363c6746794d097d9c707 (diff) | |
| download | linux-52bce7f8d4fc633c9a9d0646eef58ba6ae9a3b73.tar.xz | |
pty, n_tty: Simplify input processing on final close
When releasing one end of a pty pair, that end may just have written
to the other, which the input processing worker, flush_to_ldisc(), is
still working on but has not completed the copy to the other end's
read buffer. So input may not appear to be available to a waiting
reader but yet TTY_OTHER_CLOSED is now observed. The n_tty line
discipline has worked around this by waiting for input processing
to complete and then re-checking if input is available before
exiting with -EIO.
Since the tty/ldisc lock reordering, the wait for input processing
to complete can now occur during final close before setting
TTY_OTHER_CLOSED. In this way, a waiting reader is guaranteed to
see input available (if any) before observing TTY_OTHER_CLOSED.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/pty.c')
| -rw-r--r-- | drivers/tty/pty.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index bee9776730fd..a9d256d6e909 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -53,6 +53,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp) /* Review - krefs on tty_link ?? */ if (!tty->link) return; + tty_flush_to_ldisc(tty->link); set_bit(TTY_OTHER_CLOSED, &tty->link->flags); wake_up_interruptible(&tty->link->read_wait); wake_up_interruptible(&tty->link->write_wait); |