diff options
| -rw-r--r-- | drivers/char/tty_io.c | 24 | ||||
| -rw-r--r-- | drivers/char/tty_ldisc.c | 97 | ||||
| -rw-r--r-- | include/linux/tty.h | 3 |
3 files changed, 88 insertions, 36 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 6c817398232..be49d0730bb 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2481,6 +2481,24 @@ static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int return tty->ops->tiocmset(tty, file, set, clear); } +struct tty_struct *tty_pair_get_tty(struct tty_struct *tty) +{ + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_MASTER) + tty = tty->link; + return tty; +} +EXPORT_SYMBOL(tty_pair_get_tty); + +struct tty_struct *tty_pair_get_pty(struct tty_struct *tty) +{ + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_MASTER) + return tty; + return tty->link; +} +EXPORT_SYMBOL(tty_pair_get_pty); + /* * Split this up, as gcc can choke on it otherwise.. */ @@ -2496,11 +2514,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if (tty_paranoia_check(tty, inode, "tty_ioctl")) return -EINVAL; - real_tty = tty; - if (tty->driver->type == TTY_DRIVER_TYPE_PTY && - tty->driver->subtype == PTY_TYPE_MASTER) - real_tty = tty->link; - + real_tty = tty_pair_get_tty(tty); /* * Factor out some common prep work diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c index f78f5b0127a..e3c6416aa86 100644 --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -444,6 +444,50 @@ static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old) } /** + * tty_ldisc_halt - shutdown the line discipline + * @tty: tty device + * + * Shut down the line discipline and work queue for this tty device. + * The TTY_LDISC flag being cleared ensures no further references can + * be obtained while the delayed work queue halt ensures that no more + * data is fed to the ldisc. + * + * In order to wait for any existing references to complete see + * tty_ldisc_wait_idle. + */ + +static void tty_ldisc_halt(struct tty_struct *tty) +{ + clear_bit(TTY_LDISC, &tty->flags); + cancel_delayed_work(&tty->buf.work); + /* + * Wait for ->hangup_work and ->buf.work handlers to terminate + */ + flush_scheduled_work(); +} + +/** + * tty_ldisc_wait_idle - wait for the ldisc to become idle + * @tty: tty to wait for + * + * Wait for the line discipline to become idle. The discipline must + * have been halted for this to guarantee it remains idle. + * + */ + +static void tty_ldisc_wait_idle(struct tty_struct *tty) +{ + unsigned long flags; + spin_lock_irqsave(&tty_ldisc_lock, flags); + while (tty->ldisc.refcount) { + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); + spin_lock_irqsave(&tty_ldisc_lock, flags); + } + spin_unlock_irqrestore(&tty_ldisc_lock, flags); +} + +/** * tty_set_ldisc - set line discipline * @tty: the terminal to set * @ldisc: the line discipline @@ -636,6 +680,21 @@ int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty) return 0; } +static void tty_ldisc_reinit(struct tty_struct *tty) +{ + struct tty_ldisc ld; + + if (tty->ldisc.ops->close) + (tty->ldisc.ops->close)(tty); + tty_ldisc_put(tty->ldisc.ops); + /* + * Switch the line discipline back + */ + WARN_ON(tty_ldisc_get(N_TTY, &ld)); + tty_ldisc_assign(tty, &ld); + tty_set_termios_ldisc(tty, N_TTY); +} + /** * tty_ldisc_release - release line discipline * @tty: tty being shut down @@ -647,58 +706,34 @@ int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty) void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty) { - unsigned long flags; - struct tty_ldisc ld; + /* * Prevent flush_to_ldisc() from rescheduling the work for later. Then * kill any delayed work. As this is the final close it does not * race with the set_ldisc code path. */ - clear_bit(TTY_LDISC, &tty->flags); - cancel_delayed_work(&tty->buf.work); - /* - * Wait for ->hangup_work and ->buf.work handlers to terminate - */ - - flush_scheduled_work(); + tty_ldisc_halt(tty); /* * Wait for any short term users (we know they are just driver * side waiters as the file is closing so user count on the file * side is zero. */ - spin_lock_irqsave(&tty_ldisc_lock, flags); - while (tty->ldisc.refcount) { - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); - spin_lock_irqsave(&tty_ldisc_lock, flags); - } - spin_unlock_irqrestore(&tty_ldisc_lock, flags); + + tty_ldisc_wait_idle(tty); + /* * Shutdown the current line discipline, and reset it to N_TTY. * * FIXME: this MUST get fixed for the new reflocking */ - if (tty->ldisc.ops->close) - (tty->ldisc.ops->close)(tty); - tty_ldisc_put(tty->ldisc.ops); - /* - * Switch the line discipline back - */ - WARN_ON(tty_ldisc_get(N_TTY, &ld)); - tty_ldisc_assign(tty, &ld); - tty_set_termios_ldisc(tty, N_TTY); + tty_ldisc_reinit(tty); if (o_tty) { /* FIXME: could o_tty be in setldisc here ? */ clear_bit(TTY_LDISC, &o_tty->flags); - if (o_tty->ldisc.ops->close) - (o_tty->ldisc.ops->close)(o_tty); - tty_ldisc_put(o_tty->ldisc.ops); - WARN_ON(tty_ldisc_get(N_TTY, &ld)); - tty_ldisc_assign(o_tty, &ld); - tty_set_termios_ldisc(o_tty, N_TTY); + tty_ldisc_reinit(o_tty); } } diff --git a/include/linux/tty.h b/include/linux/tty.h index bed5a3d4030..f9c13c83790 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -428,6 +428,9 @@ extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx, extern void tty_release_dev(struct file *filp); extern int tty_init_termios(struct tty_struct *tty); +extern struct tty_struct *tty_pair_get_tty(struct tty_struct *tty); +extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty); + extern struct mutex tty_mutex; extern void tty_write_unlock(struct tty_struct *tty); |