From 36b3c070d2346c890d690d71f6eab02f8c511137 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Tue, 17 Jul 2012 17:06:57 +0100 Subject: [PATCH] tty: Move the handling of the tty release logic Now that we don't have tty->termios tied to drivers->tty we can untangle the logic here. In addition we can push the removal logic out of the destructor path. At that point we can think about sorting out tty_port and console and all the other ugly hangovers. Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/pty.c | 12 ++----- drivers/tty/tty_io.c | 56 ++++++++++++++++----------------- drivers/tty/vt/vt.c | 1 - drivers/usb/serial/usb-serial.c | 3 +- include/linux/tty.h | 1 - include/linux/tty_driver.h | 11 ++----- 6 files changed, 34 insertions(+), 50 deletions(-) diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 5ad7ccc49f74..60c08ce83782 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -527,12 +527,6 @@ static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, return tty; } -static void pty_unix98_shutdown(struct tty_struct *tty) -{ - tty_driver_remove_tty(tty->driver, tty); - /* We have our own method as we don't use the tty index */ -} - /* We have no need to install and remove our tty objects as devpts does all the work for us */ @@ -558,9 +552,8 @@ static const struct tty_operations ptm_unix98_ops = { .unthrottle = pty_unthrottle, .set_termios = pty_set_termios, .ioctl = pty_unix98_ioctl, - .shutdown = pty_unix98_shutdown, - .cleanup = pty_cleanup, - .resize = pty_resize + .resize = pty_resize, + .cleanup = pty_cleanup }; static const struct tty_operations pty_unix98_ops = { @@ -575,7 +568,6 @@ static const struct tty_operations pty_unix98_ops = { .chars_in_buffer = pty_chars_in_buffer, .unthrottle = pty_unthrottle, .set_termios = pty_set_termios, - .shutdown = pty_unix98_shutdown, .cleanup = pty_cleanup, }; diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index cfd12da81218..be18d60ddf4c 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1249,16 +1249,16 @@ int tty_init_termios(struct tty_struct *tty) struct ktermios *tp; int idx = tty->index; - tp = tty->driver->termios[idx]; - if (tp == NULL) { - tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); - if (tp == NULL) - return -ENOMEM; - *tp = tty->driver->init_termios; - tty->driver->termios[idx] = tp; + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) + tty->termios = tty->driver->init_termios; + else { + /* Check for lazy saved data */ + tp = tty->driver->termios[idx]; + if (tp != NULL) + tty->termios = *tp; + else + tty->termios = tty->driver->init_termios; } - tty->termios = *tp; - /* Compatibility until drivers always set this */ tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios); tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios); @@ -1437,24 +1437,24 @@ 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->driver->termios[idx]; - tty->driver->termios[idx] = NULL; - kfree(tp); + + /* If the port is going to reset then it has no termios to save */ + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) + return; + + /* Stash the termios data */ + tp = tty->driver->termios[idx]; + if (tp == NULL) { + tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); + if (tp == NULL) { + pr_warn("tty: no memory to save termios state.\n"); + return; + } } - else - *tty->driver->termios[idx] = tty->termios; + *tp = tty->termios; } EXPORT_SYMBOL(tty_free_termios); -void tty_shutdown(struct tty_struct *tty) -{ - tty_driver_remove_tty(tty->driver, tty); - tty_free_termios(tty); -} -EXPORT_SYMBOL(tty_shutdown); /** * release_one_tty - release tty structure memory @@ -1498,11 +1498,6 @@ static void queue_release_one_tty(struct kref *kref) { struct tty_struct *tty = container_of(kref, struct tty_struct, kref); - if (tty->ops->shutdown) - tty->ops->shutdown(tty); - else - tty_shutdown(tty); - /* The hangup queue is now free so we can reuse it rather than waste a chunk of memory for each port */ INIT_WORK(&tty->hangup_work, release_one_tty); @@ -1542,6 +1537,11 @@ static void release_tty(struct tty_struct *tty, int idx) /* This should always be true but check for the moment */ WARN_ON(tty->index != idx); + if (tty->ops->shutdown) + tty->ops->shutdown(tty); + tty_free_termios(tty); + tty_driver_remove_tty(tty->driver, tty); + if (tty->link) tty_kref_put(tty->link); tty_kref_put(tty); diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index dbceaeb2c3eb..e07ded30fc7f 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -2850,7 +2850,6 @@ static void con_shutdown(struct tty_struct *tty) console_lock(); vc->port.tty = NULL; console_unlock(); - tty_shutdown(tty); } static int default_italic_color = 2; // green (ASCII) diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index 5fe21357b55c..aa4b0d775992 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -305,8 +305,7 @@ static void serial_close(struct tty_struct *tty, struct file *filp) * Do the resource freeing and refcount dropping for the port. * Avoid freeing the console. * - * Called asynchronously after the last tty kref is dropped, - * and the tty layer has already done the tty_shutdown(tty); + * Called asynchronously after the last tty kref is dropped. */ static void serial_cleanup(struct tty_struct *tty) { diff --git a/include/linux/tty.h b/include/linux/tty.h index d5e75ee0f4d1..a39e72325e78 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -423,7 +423,6 @@ extern void tty_unthrottle(struct tty_struct *tty); extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws); extern void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty); -extern void tty_shutdown(struct tty_struct *tty); extern void tty_free_termios(struct tty_struct *tty); extern int is_current_pgrp_orphaned(void); extern struct pid *tty_get_pgrp(struct tty_struct *tty); diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 04419c141b00..80e72dc564a5 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -45,14 +45,9 @@ * * void (*shutdown)(struct tty_struct * tty); * - * This routine is called synchronously when a particular tty device - * is closed for the last time freeing up the resources. - * Note that tty_shutdown() is not called if ops->shutdown is defined. - * This means one is responsible to take care of calling ops->remove (e.g. - * via tty_driver_remove_tty) and releasing tty->termios. - * Note that this hook may be called from *all* the contexts where one - * uses tty refcounting (e.g. tty_port_tty_get). - * + * This routine is called under the tty lock when a particular tty device + * is closed for the last time. It executes before the tty resources + * are freed so may execute while another function holds a tty kref. * * void (*cleanup)(struct tty_struct * tty); * -- 2.20.1