From 7d7b93c1452f381350dbaf276a63357fa6559e6d Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Mon, 13 Oct 2008 10:42:09 +0100 Subject: tty: kref the tty driver object Signed-off-by: Alan Cox Signed-off-by: Linus Torvalds --- drivers/char/tty_io.c | 110 ++++++++++++++++++++++++++++---------------------- 1 file changed, 61 insertions(+), 49 deletions(-) (limited to 'drivers/char/tty_io.c') diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index ac41af8763d..47aa437effe 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -276,7 +276,7 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index) if (device < base || device >= base + p->num) continue; *index = device - base; - return p; + return tty_driver_kref_get(p); } return NULL; } @@ -320,7 +320,7 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line) if (tty_line >= 0 && tty_line <= p->num && p->ops && p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) { - res = p; + res = tty_driver_kref_get(p); *line = tty_line; break; } @@ -1410,7 +1410,7 @@ int tty_init_dev(struct tty_driver *driver, int idx, *o_ltp_loc = o_ltp; o_tty->termios = *o_tp_loc; o_tty->termios_locked = *o_ltp_loc; - driver->other->refcount++; + tty_driver_kref_get(driver->other); if (driver->subtype == PTY_TYPE_MASTER) o_tty->count++; @@ -1438,7 +1438,7 @@ int tty_init_dev(struct tty_driver *driver, int idx, /* 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); - driver->refcount++; + tty_driver_kref_get(driver); tty->count++; /* @@ -1530,8 +1530,7 @@ static void release_one_tty(struct kref *kref) else tty_shutdown(tty); tty->magic = 0; - /* FIXME: locking on tty->driver->refcount */ - tty->driver->refcount--; + tty_driver_kref_put(driver); module_put(driver->owner); file_list_lock(); @@ -1854,7 +1853,7 @@ retry_open: mutex_unlock(&tty_mutex); return -ENXIO; } - driver = tty->driver; + driver = tty_driver_kref_get(tty->driver); index = tty->index; filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ /* noctty = 1; */ @@ -1865,14 +1864,14 @@ retry_open: #ifdef CONFIG_VT if (device == MKDEV(TTY_MAJOR, 0)) { extern struct tty_driver *console_driver; - driver = console_driver; + driver = tty_driver_kref_get(console_driver); index = fg_console; noctty = 1; goto got_driver; } #endif if (device == MKDEV(TTYAUX_MAJOR, 1)) { - driver = console_device(&index); + driver = tty_driver_kref_get(console_device(&index)); if (driver) { /* Don't let /dev/console block */ filp->f_flags |= O_NONBLOCK; @@ -1891,6 +1890,7 @@ retry_open: got_driver: retval = tty_init_dev(driver, index, &tty, 0); mutex_unlock(&tty_mutex); + tty_driver_kref_put(driver); if (retval) return retval; @@ -2866,7 +2866,6 @@ int tty_put_char(struct tty_struct *tty, unsigned char ch) return tty->ops->put_char(tty, ch); return tty->ops->write(tty, &ch, 1); } - EXPORT_SYMBOL_GPL(tty_put_char); struct class *tty_class; @@ -2909,6 +2908,7 @@ struct device *tty_register_device(struct tty_driver *driver, unsigned index, return device_create_drvdata(tty_class, device, dev, NULL, name); } +EXPORT_SYMBOL(tty_register_device); /** * tty_unregister_device - unregister a tty device @@ -2926,8 +2926,6 @@ void tty_unregister_device(struct tty_driver *driver, unsigned index) device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); } - -EXPORT_SYMBOL(tty_register_device); EXPORT_SYMBOL(tty_unregister_device); struct tty_driver *alloc_tty_driver(int lines) @@ -2936,27 +2934,70 @@ struct tty_driver *alloc_tty_driver(int lines) driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); if (driver) { + kref_init(&driver->kref); driver->magic = TTY_DRIVER_MAGIC; driver->num = lines; /* later we'll move allocation of tables here */ } return driver; } +EXPORT_SYMBOL(alloc_tty_driver); -void put_tty_driver(struct tty_driver *driver) +static void destruct_tty_driver(struct kref *kref) { + struct tty_driver *driver = container_of(kref, struct tty_driver, kref); + int i; + struct ktermios *tp; + void *p; + + if (driver->flags & TTY_DRIVER_INSTALLED) { + /* + * Free the termios and termios_locked structures because + * we don't want to get memory leaks when modular tty + * drivers are removed from the kernel. + */ + for (i = 0; i < driver->num; i++) { + tp = driver->termios[i]; + if (tp) { + driver->termios[i] = NULL; + kfree(tp); + } + tp = driver->termios_locked[i]; + if (tp) { + driver->termios_locked[i] = NULL; + kfree(tp); + } + if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) + tty_unregister_device(driver, i); + } + p = driver->ttys; + proc_tty_unregister_driver(driver); + driver->ttys = NULL; + driver->termios = driver->termios_locked = NULL; + kfree(p); + cdev_del(&driver->cdev); + } kfree(driver); } +void tty_driver_kref_put(struct tty_driver *driver) +{ + kref_put(&driver->kref, destruct_tty_driver); +} +EXPORT_SYMBOL(tty_driver_kref_put); + void tty_set_operations(struct tty_driver *driver, const struct tty_operations *op) { driver->ops = op; }; +EXPORT_SYMBOL(tty_set_operations); -EXPORT_SYMBOL(alloc_tty_driver); +void put_tty_driver(struct tty_driver *d) +{ + tty_driver_kref_put(d); +} EXPORT_SYMBOL(put_tty_driver); -EXPORT_SYMBOL(tty_set_operations); /* * Called by a tty driver to register itself. @@ -2968,9 +3009,6 @@ int tty_register_driver(struct tty_driver *driver) dev_t dev; void **p = NULL; - if (driver->flags & TTY_DRIVER_INSTALLED) - return 0; - if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); if (!p) @@ -3024,6 +3062,7 @@ int tty_register_driver(struct tty_driver *driver) tty_register_device(driver, i, NULL); } proc_tty_register_driver(driver); + driver->flags |= TTY_DRIVER_INSTALLED; return 0; } @@ -3034,46 +3073,19 @@ EXPORT_SYMBOL(tty_register_driver); */ int tty_unregister_driver(struct tty_driver *driver) { - int i; - struct ktermios *tp; - void *p; - +#if 0 + /* FIXME */ if (driver->refcount) return -EBUSY; - +#endif unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), driver->num); mutex_lock(&tty_mutex); list_del(&driver->tty_drivers); mutex_unlock(&tty_mutex); - - /* - * Free the termios and termios_locked structures because - * we don't want to get memory leaks when modular tty - * drivers are removed from the kernel. - */ - for (i = 0; i < driver->num; i++) { - tp = driver->termios[i]; - if (tp) { - driver->termios[i] = NULL; - kfree(tp); - } - tp = driver->termios_locked[i]; - if (tp) { - driver->termios_locked[i] = NULL; - kfree(tp); - } - if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) - tty_unregister_device(driver, i); - } - p = driver->ttys; - proc_tty_unregister_driver(driver); - driver->ttys = NULL; - driver->termios = driver->termios_locked = NULL; - kfree(p); - cdev_del(&driver->cdev); return 0; } + EXPORT_SYMBOL(tty_unregister_driver); dev_t tty_devnum(struct tty_struct *tty) -- cgit v1.2.3