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tty: kref the tty driver object

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Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox
2008-10-13 10:42:09 +01:00
committed by Linus Torvalds
parent 99f1fe189d
commit 7d7b93c145
5 changed files with 81 additions and 59 deletions
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112
drivers/char/tty_io.c
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@@ -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)
@@ -2936,28 +2934,71 @@ 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(alloc_tty_driver);
EXPORT_SYMBOL(put_tty_driver);
EXPORT_SYMBOL(tty_set_operations);
void put_tty_driver(struct tty_driver *d)
{
tty_driver_kref_put(d);
}
EXPORT_SYMBOL(put_tty_driver);
/*
* 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)