diff options
| -rw-r--r-- | drivers/tty/tty_io.c | 39 | ||||
| -rw-r--r-- | include/linux/tty.h | 5 | ||||
| -rw-r--r-- | include/linux/tty_driver.h | 4 |
3 files changed, 36 insertions, 12 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index d4eb2a8b7047..b8ddfef6b5d8 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -919,18 +919,18 @@ void no_tty(void) * but not always. * * Locking: - * Uses the tty control lock internally + * ctrl_lock + * 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; + spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->link && tty->link->packet) { tty->ctrl_status &= ~TIOCPKT_START; tty->ctrl_status |= TIOCPKT_STOP; @@ -941,6 +941,14 @@ void stop_tty(struct tty_struct *tty) (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); /** @@ -954,17 +962,17 @@ EXPORT_SYMBOL(stop_tty); * * 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; + spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->link && tty->link->packet) { tty->ctrl_status &= ~TIOCPKT_STOP; tty->ctrl_status |= TIOCPKT_START; @@ -977,6 +985,14 @@ void start_tty(struct tty_struct *tty) 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. */ @@ -3019,6 +3035,7 @@ 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); diff --git a/include/linux/tty.h b/include/linux/tty.h index 4cfd4a82fc31..fd4148d3a261 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -252,6 +252,7 @@ struct tty_struct { struct rw_semaphore termios_rwsem; struct mutex winsize_mutex; spinlock_t ctrl_lock; + spinlock_t flow_lock; /* Termios values are protected by the termios rwsem */ struct ktermios termios, termios_locked; struct termiox *termiox; /* May be NULL for unsupported */ @@ -261,7 +262,7 @@ struct tty_struct { unsigned long flags; int count; struct winsize winsize; /* winsize_mutex */ - int stopped; + int stopped; /* flow_lock */ int flow_stopped; int hw_stopped; int packet; @@ -400,7 +401,9 @@ extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, extern char *tty_name(struct tty_struct *tty, char *buf); extern void tty_wait_until_sent(struct tty_struct *tty, long timeout); extern int tty_check_change(struct tty_struct *tty); +extern void __stop_tty(struct tty_struct *tty); extern void stop_tty(struct tty_struct *tty); +extern void __start_tty(struct tty_struct *tty); extern void start_tty(struct tty_struct *tty); extern int tty_register_driver(struct tty_driver *driver); extern int tty_unregister_driver(struct tty_driver *driver); diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index e48c608a8fa8..92e337c18839 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -152,6 +152,8 @@ * This routine notifies the tty driver that it should stop * outputting characters to the tty device. * + * Called with ->flow_lock held. Serialized with start() method. + * * Optional: * * Note: Call stop_tty not this method. @@ -161,6 +163,8 @@ * This routine notifies the tty driver that it resume sending * characters to the tty device. * + * Called with ->flow_lock held. Serialized with stop() method. + * * Optional: * * Note: Call start_tty not this method. |