diff options
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 114 |
1 files changed, 74 insertions, 40 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 8fbad3410c75..0508a1d8e4cd 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -908,8 +908,7 @@ void no_tty(void) * stop_tty - propagate flow control * @tty: tty to stop * - * Perform flow control to the driver. For PTY/TTY pairs we - * must also propagate the TIOCKPKT status. May be called + * Perform flow control to the driver. May be called * on an already stopped device and will not re-call the driver * method. * @@ -919,64 +918,58 @@ void no_tty(void) * but not always. * * Locking: - * Uses the tty control lock internally + * flow_lock */ -void stop_tty(struct tty_struct *tty) +void __stop_tty(struct tty_struct *tty) { - unsigned long flags; - spin_lock_irqsave(&tty->ctrl_lock, flags); - if (tty->stopped) { - spin_unlock_irqrestore(&tty->ctrl_lock, flags); + if (tty->stopped) return; - } tty->stopped = 1; - if (tty->link && tty->link->packet) { - tty->ctrl_status &= ~TIOCPKT_START; - tty->ctrl_status |= TIOCPKT_STOP; - wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); - } - spin_unlock_irqrestore(&tty->ctrl_lock, flags); if (tty->ops->stop) (tty->ops->stop)(tty); } +void stop_tty(struct tty_struct *tty) +{ + unsigned long flags; + + spin_lock_irqsave(&tty->flow_lock, flags); + __stop_tty(tty); + spin_unlock_irqrestore(&tty->flow_lock, flags); +} EXPORT_SYMBOL(stop_tty); /** * start_tty - propagate flow control * @tty: tty to start * - * Start a tty that has been stopped if at all possible. Perform - * any necessary wakeups and propagate the TIOCPKT status. If this - * is the tty was previous stopped and is being started then the - * driver start method is invoked and the line discipline woken. + * Start a tty that has been stopped if at all possible. If this + * tty was previous stopped and is now being started, the driver + * start method is invoked and the line discipline woken. * * Locking: - * ctrl_lock + * flow_lock */ -void start_tty(struct tty_struct *tty) +void __start_tty(struct tty_struct *tty) { - unsigned long flags; - spin_lock_irqsave(&tty->ctrl_lock, flags); - if (!tty->stopped || tty->flow_stopped) { - spin_unlock_irqrestore(&tty->ctrl_lock, flags); + if (!tty->stopped || tty->flow_stopped) return; - } tty->stopped = 0; - if (tty->link && tty->link->packet) { - tty->ctrl_status &= ~TIOCPKT_STOP; - tty->ctrl_status |= TIOCPKT_START; - wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); - } - spin_unlock_irqrestore(&tty->ctrl_lock, flags); if (tty->ops->start) (tty->ops->start)(tty); - /* If we have a running line discipline it may need kicking */ tty_wakeup(tty); } +void start_tty(struct tty_struct *tty) +{ + unsigned long flags; + + spin_lock_irqsave(&tty->flow_lock, flags); + __start_tty(tty); + spin_unlock_irqrestore(&tty->flow_lock, flags); +} EXPORT_SYMBOL(start_tty); /* We limit tty time update visibility to every 8 seconds or so. */ @@ -1030,14 +1023,14 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count, return i; } -void tty_write_unlock(struct tty_struct *tty) +static void tty_write_unlock(struct tty_struct *tty) __releases(&tty->atomic_write_lock) { mutex_unlock(&tty->atomic_write_lock); wake_up_interruptible_poll(&tty->write_wait, POLLOUT); } -int tty_write_lock(struct tty_struct *tty, int ndelay) +static int tty_write_lock(struct tty_struct *tty, int ndelay) __acquires(&tty->atomic_write_lock) { if (!mutex_trylock(&tty->atomic_write_lock)) { @@ -1224,6 +1217,35 @@ ssize_t redirected_tty_write(struct file *file, const char __user *buf, return tty_write(file, buf, count, ppos); } +/** + * tty_send_xchar - send priority character + * + * Send a high priority character to the tty even if stopped + * + * Locking: none for xchar method, write ordering for write method. + */ + +int tty_send_xchar(struct tty_struct *tty, char ch) +{ + int was_stopped = tty->stopped; + + if (tty->ops->send_xchar) { + tty->ops->send_xchar(tty, ch); + return 0; + } + + if (tty_write_lock(tty, 0) < 0) + return -ERESTARTSYS; + + if (was_stopped) + start_tty(tty); + tty->ops->write(tty, &ch, 1); + if (was_stopped) + stop_tty(tty); + tty_write_unlock(tty); + return 0; +} + static char ptychar[] = "pqrstuvwxyzabcde"; /** @@ -1544,13 +1566,14 @@ static void release_one_tty(struct work_struct *work) struct tty_struct *tty = container_of(work, struct tty_struct, hangup_work); struct tty_driver *driver = tty->driver; + struct module *owner = driver->owner; if (tty->ops->cleanup) tty->ops->cleanup(tty); tty->magic = 0; tty_driver_kref_put(driver); - module_put(driver->owner); + module_put(owner); spin_lock(&tty_files_lock); list_del_init(&tty->tty_files); @@ -1686,6 +1709,8 @@ int tty_release(struct inode *inode, struct file *filp) int pty_master, tty_closing, o_tty_closing, do_sleep; int idx; char buf[64]; + long timeout = 0; + int once = 1; if (tty_paranoia_check(tty, inode, __func__)) return 0; @@ -1766,11 +1791,18 @@ int tty_release(struct inode *inode, struct file *filp) if (!do_sleep) break; - printk(KERN_WARNING "%s: %s: read/write wait queue active!\n", - __func__, tty_name(tty, buf)); + if (once) { + once = 0; + printk(KERN_WARNING "%s: %s: read/write wait queue active!\n", + __func__, tty_name(tty, buf)); + } tty_unlock_pair(tty, o_tty); mutex_unlock(&tty_mutex); - schedule(); + schedule_timeout_killable(timeout); + if (timeout < 120 * HZ) + timeout = 2 * timeout + 1; + else + timeout = MAX_SCHEDULE_TIMEOUT; } /* @@ -2163,8 +2195,9 @@ static int __tty_fasync(int fd, struct file *filp, int on) } get_pid(pid); spin_unlock_irqrestore(&tty->ctrl_lock, flags); - retval = __f_setown(filp, pid, type, 0); + __f_setown(filp, pid, type, 0); put_pid(pid); + retval = 0; } out: return retval; @@ -3018,6 +3051,7 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx) INIT_WORK(&tty->hangup_work, do_tty_hangup); mutex_init(&tty->atomic_write_lock); spin_lock_init(&tty->ctrl_lock); + spin_lock_init(&tty->flow_lock); INIT_LIST_HEAD(&tty->tty_files); INIT_WORK(&tty->SAK_work, do_SAK_work); |