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tty: More driver operations

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We have the lookup operation abstracted which is nice for pty cleanup but
we really want to abstract the add/remove entries as well so that we can
pull the pty code out of the tty core and create a clear defined interface
for the tty driver table.

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 10:42:19 +01:00 committed by Linus Torvalds
parent 7d7b93c145
commit 8b0a88d591
3 changed files with 79 additions and 10 deletions
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16
drivers/char/pty.c
View file

@ -433,8 +433,22 @@ static void pty_shutdown(struct tty_struct *tty)
kfree(tty->termios_locked);
}
/* We have no need to install and remove our tty objects as devpts does all
the work for us */
static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
{
return 0;
}
static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
{
}
static const struct tty_operations ptm_unix98_ops = {
.lookup = ptm_unix98_lookup,
.install = pty_install,
.remove = pty_remove,
.open = pty_open,
.close = pty_close,
.write = pty_write,
@ -449,6 +463,8 @@ static const struct tty_operations ptm_unix98_ops = {
static const struct tty_operations pty_unix98_ops = {
.lookup = pts_unix98_lookup,
.install = pty_install,
.remove = pty_remove,
.open = pty_open,
.close = pty_close,
.write = pty_write,

57
drivers/char/tty_io.c
View file

@ -1189,7 +1189,7 @@ static void pty_line_name(struct tty_driver *driver, int index, char *p)
}
/**
* pty_line_name - generate name for a tty
* tty_line_name - generate name for a tty
* @driver: the tty driver in use
* @index: the minor number
* @p: output buffer of at least 7 bytes
@ -1222,13 +1222,51 @@ struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, int idx)
if (driver->ops->lookup)
return driver->ops->lookup(driver, idx);
tty = driver->ttys[idx];
tty = driver->ttys[idx];
return tty;
}
/**
* tty_reopen() - fast re-open of an open tty
* @tty - the tty to open
* tty_driver_install_tty() - install a tty entry in the driver
* @driver: the driver for the tty
* @tty: the tty
*
* Install a tty object into the driver tables. The tty->index field
* will be set by the time this is called.
*
* Locking: tty_mutex for now
*/
static int tty_driver_install_tty(struct tty_driver *driver,
struct tty_struct *tty)
{
if (driver->ops->install)
return driver->ops->install(driver, tty);
driver->ttys[tty->index] = tty;
return 0;
}
/**
* tty_driver_remove_tty() - remove a tty from the driver tables
* @driver: the driver for the tty
* @idx: the minor number
*
* Remvoe a tty object from the driver tables. The tty->index field
* will be set by the time this is called.
*
* Locking: tty_mutex for now
*/
static void tty_driver_remove_tty(struct tty_driver *driver,
struct tty_struct *tty)
{
if (driver->ops->remove)
driver->ops->remove(driver, tty);
else
driver->ttys[tty->index] = NULL;
}
/*
* tty_reopen() - fast re-open of an open tty
* @tty - the tty to open
*
* Return 0 on success, -errno on error.
*
@ -1423,11 +1461,7 @@ int tty_init_dev(struct tty_driver *driver, int idx,
* All structures have been allocated, so now we install them.
* Failures after this point use release_tty to clean up, so
* there's no need to null out the local pointers.
*
* FIXME: We want a 'driver->install method ?
*/
if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM))
driver->ttys[idx] = tty;
if (!*tp_loc)
*tp_loc = tp;
@ -1441,6 +1475,9 @@ int tty_init_dev(struct tty_driver *driver, int idx,
tty_driver_kref_get(driver);
tty->count++;
if (tty_driver_install_tty(driver, tty) < 0)
goto release_mem_out;
/*
* Structures all installed ... call the ldisc open routines.
* If we fail here just call release_tty to clean up. No need
@ -1502,7 +1539,7 @@ EXPORT_SYMBOL(tty_free_termios);
void tty_shutdown(struct tty_struct *tty)
{
tty->driver->ttys[tty->index] = NULL;
tty_driver_remove_tty(tty->driver, tty);
tty_free_termios(tty);
}
EXPORT_SYMBOL(tty_shutdown);
@ -1615,7 +1652,7 @@ void tty_release_dev(struct file *filp)
"free (%s)\n", tty->name);
return;
}
if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
if (!devpts) {
if (tty != tty->driver->ttys[idx]) {
printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
"for (%s)\n", idx, tty->name);

16
include/linux/tty_driver.h
View file

@ -15,6 +15,20 @@
*
* Optional method. Default behaviour is to use the ttys array
*
* int (*install)(struct tty_driver *self, struct tty_struct *tty)
*
* Install a new tty into the tty driver internal tables. Used in
* conjunction with lookup and remove methods.
*
* Optional method. Default behaviour is to use the ttys array
*
* void (*remove)(struct tty_driver *self, struct tty_struct *tty)
*
* Remove a closed tty from the tty driver internal tables. Used in
* conjunction with lookup and remove methods.
*
* Optional method. Default behaviour is to use the ttys array
*
* int (*open)(struct tty_struct * tty, struct file * filp);
*
* This routine is called when a particular tty device is opened.
@ -212,6 +226,8 @@ struct tty_driver;
struct tty_operations {
struct tty_struct * (*lookup)(struct tty_driver *driver, int idx);
int (*install)(struct tty_driver *driver, struct tty_struct *tty);
void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
int (*open)(struct tty_struct * tty, struct file * filp);
void (*close)(struct tty_struct * tty, struct file * filp);
void (*shutdown)(struct tty_struct *tty);