From feebed6515a113eeb33919e9557a8b9710ea627c Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Mon, 13 Oct 2008 10:41:30 +0100 Subject: tty: shutdown method Right now there are various drivers that try to use tty->count to know when they get the final close. Aristeau Rozanski showed while debugging the vt sysfs race that this isn't entirely safe. Instead of driver side tricks to work around this introduce a shutdown which is called when the tty is being destructed. This also means that the shutdown method is tied into the refcounting. Use this to rework the console close/sysfs logic. Remove lots of special case code from the tty core code. The pty code can now have a shutdown() method that replaces the special case hackery in the tree free up paths. Signed-off-by: Alan Cox Signed-off-by: Linus Torvalds --- drivers/char/tty_io.c | 49 +++++++++++++++++++++++++++++-------------------- 1 file changed, 29 insertions(+), 20 deletions(-) (limited to 'drivers/char/tty_io.c') diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 2e96ce0fddc..f91704d57a4 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1482,6 +1482,31 @@ release_mem_out: goto end_init; } +void tty_free_termios(struct tty_struct *tty) +{ + struct ktermios *tp; + int idx = tty->index; + /* Kill this flag and push into drivers for locking etc */ + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { + /* FIXME: Locking on ->termios array */ + tp = tty->termios; + tty->driver->termios[idx] = NULL; + kfree(tp); + + tp = tty->termios_locked; + tty->driver->termios_locked[idx] = NULL; + kfree(tp); + } +} +EXPORT_SYMBOL(tty_free_termios); + +void tty_shutdown(struct tty_struct *tty) +{ + tty->driver->ttys[tty->index] = NULL; + tty_free_termios(tty); +} +EXPORT_SYMBOL(tty_shutdown); + /** * release_one_tty - release tty structure memory * @kref: kref of tty we are obliterating @@ -1499,27 +1524,11 @@ static void release_one_tty(struct kref *kref) { struct tty_struct *tty = container_of(kref, struct tty_struct, kref); struct tty_driver *driver = tty->driver; - int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; - struct ktermios *tp; - int idx = tty->index; - - if (!devpts) - tty->driver->ttys[idx] = NULL; - - if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { - /* FIXME: Locking on ->termios array */ - tp = tty->termios; - if (!devpts) - tty->driver->termios[idx] = NULL; - kfree(tp); - - tp = tty->termios_locked; - if (!devpts) - tty->driver->termios_locked[idx] = NULL; - kfree(tp); - } - + if (tty->ops->shutdown) + tty->ops->shutdown(tty); + else + tty_shutdown(tty); tty->magic = 0; /* FIXME: locking on tty->driver->refcount */ tty->driver->refcount--; -- cgit v1.2.3