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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: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby 2012-08-08 22:26:43 +02:00 committed by Greg Kroah-Hartman
parent 16a02081ba
commit 0019b4089c
3 changed files with 15 additions and 15 deletions
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17
drivers/char/ttyprintk.c
View File

@ -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:

7
drivers/tty/tty_io.c
View File

@ -1216,7 +1216,10 @@ 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)
{
sprintf(p, "%s%d", driver->name, index + driver->name_base);
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);

6
include/linux/tty_driver.h
View File

@ -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