From 8b0a88d5912ab549d5adac2c8498ecdaae5319a5 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Mon, 13 Oct 2008 10:42:19 +0100 Subject: [PATCH] tty: More driver operations 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 Signed-off-by: Linus Torvalds --- drivers/char/pty.c | 16 +++++++++++ drivers/char/tty_io.c | 57 +++++++++++++++++++++++++++++++------- include/linux/tty_driver.h | 16 +++++++++++ 3 files changed, 79 insertions(+), 10 deletions(-) diff --git a/drivers/char/pty.c b/drivers/char/pty.c index 0fdfa0517140..4e6490bda751 100644 --- a/drivers/char/pty.c +++ b/drivers/char/pty.c @@ -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, diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 47aa437effe2..888380f573dc 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -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); diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index ba891dd23550..005d06ad46a6 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -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); -- 2.20.1