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Commit 0019b408 authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman
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TTY: add support for unnumbered device nodes 



This allows drivers like ttyprintk to avoid hacks to create an
unnumbered node in /dev. It used to set TTY_DRIVER_DYNAMIC_DEV in
flags and call device_create on its own. That is incorrect, because
TTY_DRIVER_DYNAMIC_DEV may be set only if tty_register_device is
called explicitly.

Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Acked-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 16a02081

drivers/char/ttyprintk.c

+4 −13
Original line number Diff line number Diff line
@@ -178,13 +178,15 @@ static struct tty_driver *ttyprintk_driver; 
static int __init ttyprintk_init(void)

{

	int ret = -ENOMEM;

	void *rp;



	tty_port_init(&tpk_port.port);

	tpk_port.port.ops = &null_ops;

	mutex_init(&tpk_port.port_write_mutex);



	ttyprintk_driver = alloc_tty_driver(1);

	ttyprintk_driver = tty_alloc_driver(1,

			TTY_DRIVER_RESET_TERMIOS |

			TTY_DRIVER_REAL_RAW |

			TTY_DRIVER_UNNUMBERED_NODE);

	if (!ttyprintk_driver)

		return ret;
@@ -195,8 +197,6 @@ static int __init ttyprintk_init(void) 
	ttyprintk_driver->type = TTY_DRIVER_TYPE_CONSOLE;

	ttyprintk_driver->init_termios = tty_std_termios;

	ttyprintk_driver->init_termios.c_oflag = OPOST | OCRNL | ONOCR | ONLRET;

	ttyprintk_driver->flags = TTY_DRIVER_RESET_TERMIOS |

		TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;

	tty_set_operations(ttyprintk_driver, &ttyprintk_ops);



	ret = tty_register_driver(ttyprintk_driver);
@@ -205,15 +205,6 @@ static int __init ttyprintk_init(void) 
		goto error;

	}



	/* create our unnumbered device */

	rp = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 3), NULL,

				ttyprintk_driver->name);

	if (IS_ERR(rp)) {

		printk(KERN_ERR "Couldn't create ttyprintk device\n");

		ret = PTR_ERR(rp);

		goto error;

	}



	return 0;



error:

drivers/tty/tty_io.c

+5 −2
Original line number Diff line number Diff line
@@ -1216,6 +1216,9 @@ static void pty_line_name(struct tty_driver *driver, int index, char *p) 
 */

static void tty_line_name(struct tty_driver *driver, int index, char *p)

{

	if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)

		strcpy(p, driver->name);

	else

		sprintf(p, "%s%d", driver->name, index + driver->name_base);

}
@@ -3076,7 +3079,7 @@ struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, 
	struct tty_driver *driver;

	int err;



	if (!lines)

	if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))

		return ERR_PTR(-EINVAL);



	driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);

include/linux/tty_driver.h

+6 −0
Original line number Diff line number Diff line
@@ -394,6 +394,11 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d) 
 * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are

 *	needed per line for this driver as it would waste memory.

 *	The driver will take care.

 *

 * TTY_DRIVER_UNNUMBERED_NODE -- do not create numbered /dev nodes. In

 *	other words create /dev/ttyprintk and not /dev/ttyprintk0.

 *	Applicable only when a driver for a single tty device is

 *	being allocated.

 */

#define TTY_DRIVER_INSTALLED		0x0001

#define TTY_DRIVER_RESET_TERMIOS	0x0002
@@ -402,6 +407,7 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d) 
#define TTY_DRIVER_DEVPTS_MEM		0x0010

#define TTY_DRIVER_HARDWARE_BREAK	0x0020

#define TTY_DRIVER_DYNAMIC_ALLOC	0x0040

#define TTY_DRIVER_UNNUMBERED_NODE	0x0080



/* tty driver types */

#define TTY_DRIVER_TYPE_SYSTEM		0x0001