tty: make tty_class a static const structure

Now that the driver core allows for struct class to be in read-only
memory, move the tty_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/2023040250-landowner-unfitted-11f4@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2023-04-02 19:58:50 +02:00
parent 2243acd50a
commit 862d8312ee
4 changed files with 14 additions and 16 deletions

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@ -931,7 +931,7 @@ static void __init unix98_pty_init(void)
if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
panic("Couldn't register /dev/ptmx driver");
device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
device_create(&tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
}
#else

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@ -3070,7 +3070,7 @@ static struct device *tty_get_device(struct tty_struct *tty)
{
dev_t devt = tty_devnum(tty);
return class_find_device_by_devt(tty_class, devt);
return class_find_device_by_devt(&tty_class, devt);
}
@ -3143,8 +3143,6 @@ int tty_put_char(struct tty_struct *tty, unsigned char ch)
}
EXPORT_SYMBOL_GPL(tty_put_char);
struct class *tty_class;
static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
unsigned int index, unsigned int count)
{
@ -3239,7 +3237,7 @@ struct device *tty_register_device_attr(struct tty_driver *driver,
return ERR_PTR(-ENOMEM);
dev->devt = devt;
dev->class = tty_class;
dev->class = &tty_class;
dev->parent = device;
dev->release = tty_device_create_release;
dev_set_name(dev, "%s", name);
@ -3294,8 +3292,7 @@ EXPORT_SYMBOL_GPL(tty_register_device_attr);
*/
void tty_unregister_device(struct tty_driver *driver, unsigned index)
{
device_destroy(tty_class,
MKDEV(driver->major, driver->minor_start) + index);
device_destroy(&tty_class, MKDEV(driver->major, driver->minor_start) + index);
if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
cdev_del(driver->cdevs[index]);
driver->cdevs[index] = NULL;
@ -3510,13 +3507,14 @@ static char *tty_devnode(const struct device *dev, umode_t *mode)
return NULL;
}
const struct class tty_class = {
.name = "tty",
.devnode = tty_devnode,
};
static int __init tty_class_init(void)
{
tty_class = class_create("tty");
if (IS_ERR(tty_class))
return PTR_ERR(tty_class);
tty_class->devnode = tty_devnode;
return 0;
return class_register(&tty_class);
}
postcore_initcall(tty_class_init);
@ -3643,13 +3641,13 @@ int __init tty_init(void)
if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
panic("Couldn't register /dev/tty driver\n");
device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
device_create(&tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
cdev_init(&console_cdev, &console_fops);
if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
panic("Couldn't register /dev/console driver\n");
consdev = device_create_with_groups(tty_class, NULL,
consdev = device_create_with_groups(&tty_class, NULL,
MKDEV(TTYAUX_MAJOR, 1), NULL,
cons_dev_groups, "console");
if (IS_ERR(consdev))

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@ -3539,7 +3539,7 @@ int __init vty_init(const struct file_operations *console_fops)
if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
panic("Couldn't register /dev/tty0 driver\n");
tty0dev = device_create_with_groups(tty_class, NULL,
tty0dev = device_create_with_groups(&tty_class, NULL,
MKDEV(TTY_MAJOR, 0), NULL,
vt_dev_groups, "tty0");
if (IS_ERR(tty0dev))

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@ -387,7 +387,7 @@ extern struct ktermios tty_std_termios;
int vcs_init(void);
extern struct class *tty_class;
extern const struct class tty_class;
/**
* tty_kref_get - get a tty reference