diff options
| -rw-r--r-- | drivers/char/epca.c | 195 |
1 files changed, 104 insertions, 91 deletions
diff --git a/drivers/char/epca.c b/drivers/char/epca.c index da2d2cf16f55..e07d7925c300 100644 --- a/drivers/char/epca.c +++ b/drivers/char/epca.c @@ -69,7 +69,9 @@ static int invalid_lilo_config; /* * The ISA boards do window flipping into the same spaces so its only sane with - * a single lock. It's still pretty efficient. + * a single lock. It's still pretty efficient. This lock guards the hardware + * and the tty_port lock guards the kernel side stuff like use counts. Take + * this lock inside the port lock if you must take both. */ static DEFINE_SPINLOCK(epca_lock); @@ -156,7 +158,7 @@ static struct channel *verifyChannel(struct tty_struct *); static void pc_sched_event(struct channel *, int); static void epca_error(int, char *); static void pc_close(struct tty_struct *, struct file *); -static void shutdown(struct channel *); +static void shutdown(struct channel *, struct tty_struct *tty); static void pc_hangup(struct tty_struct *); static int pc_write_room(struct tty_struct *); static int pc_chars_in_buffer(struct tty_struct *); @@ -419,76 +421,78 @@ static void epca_error(int line, char *msg) static void pc_close(struct tty_struct *tty, struct file *filp) { struct channel *ch; + struct tty_port *port; unsigned long flags; /* * verifyChannel returns the channel from the tty struct if it is * valid. This serves as a sanity check. */ ch = verifyChannel(tty); - if (ch != NULL) { - spin_lock_irqsave(&epca_lock, flags); - if (tty_hung_up_p(filp)) { - spin_unlock_irqrestore(&epca_lock, flags); - return; - } - if (ch->port.count-- > 1) { - /* Begin channel is open more than once */ - /* - * Return without doing anything. Someone might still - * be using the channel. - */ - spin_unlock_irqrestore(&epca_lock, flags); - return; - } - /* Port open only once go ahead with shutdown & reset */ - BUG_ON(ch->port.count < 0); + if (ch == NULL) + return; + port = &ch->port; + spin_lock_irqsave(&port->lock, flags); + if (tty_hung_up_p(filp)) { + spin_unlock_irqrestore(&port->lock, flags); + return; + } + if (port->count-- > 1) { + /* Begin channel is open more than once */ /* - * Let the rest of the driver know the channel is being closed. - * This becomes important if an open is attempted before close - * is finished. + * Return without doing anything. Someone might still + * be using the channel. */ - ch->port.flags |= ASYNC_CLOSING; - tty->closing = 1; - - spin_unlock_irqrestore(&epca_lock, flags); - - if (ch->port.flags & ASYNC_INITIALIZED) { - /* Setup an event to indicate when the - transmit buffer empties */ - setup_empty_event(tty, ch); - /* 30 seconds timeout */ - tty_wait_until_sent(tty, 3000); - } - pc_flush_buffer(tty); + spin_unlock_irqrestore(&port->lock, flags); + return; + } + /* Port open only once go ahead with shutdown & reset */ + WARN_ON(port->count < 0); - tty_ldisc_flush(tty); - shutdown(ch); + /* + * Let the rest of the driver know the channel is being closed. + * This becomes important if an open is attempted before close + * is finished. + */ + port->flags |= ASYNC_CLOSING; + tty->closing = 1; - spin_lock_irqsave(&epca_lock, flags); - tty->closing = 0; - ch->event = 0; - ch->port.tty = NULL; - spin_unlock_irqrestore(&epca_lock, flags); + spin_unlock_irqrestore(&port->lock, flags); - if (ch->port.blocked_open) { - if (ch->close_delay) - msleep_interruptible(jiffies_to_msecs(ch->close_delay)); - wake_up_interruptible(&ch->port.open_wait); - } - ch->port.flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED | - ASYNC_CLOSING); - wake_up_interruptible(&ch->port.close_wait); + if (port->flags & ASYNC_INITIALIZED) { + /* Setup an event to indicate when the + transmit buffer empties */ + setup_empty_event(tty, ch); + /* 30 seconds timeout */ + tty_wait_until_sent(tty, 3000); + } + pc_flush_buffer(tty); + tty_ldisc_flush(tty); + shutdown(ch, tty); + + spin_lock_irqsave(&port->lock, flags); + tty->closing = 0; + ch->event = 0; + port->tty = NULL; + spin_unlock_irqrestore(&port->lock, flags); + + if (port->blocked_open) { + if (ch->close_delay) + msleep_interruptible(jiffies_to_msecs(ch->close_delay)); + wake_up_interruptible(&port->open_wait); } + port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED | + ASYNC_CLOSING); + wake_up_interruptible(&port->close_wait); } -static void shutdown(struct channel *ch) +static void shutdown(struct channel *ch, struct tty_struct *tty) { unsigned long flags; - struct tty_struct *tty; struct board_chan __iomem *bc; + struct tty_port *port = &ch->port; - if (!(ch->port.flags & ASYNC_INITIALIZED)) + if (!(port->flags & ASYNC_INITIALIZED)) return; spin_lock_irqsave(&epca_lock, flags); @@ -503,7 +507,6 @@ static void shutdown(struct channel *ch) */ if (bc) writeb(0, &bc->idata); - tty = ch->port.tty; /* If we're a modem control device and HUPCL is on, drop RTS & DTR. */ if (tty->termios->c_cflag & HUPCL) { @@ -517,13 +520,15 @@ static void shutdown(struct channel *ch) * will have to reinitialized. Set a flag to indicate this. */ /* Prevent future Digi programmed interrupts from coming active */ - ch->port.flags &= ~ASYNC_INITIALIZED; + port->flags &= ~ASYNC_INITIALIZED; spin_unlock_irqrestore(&epca_lock, flags); } static void pc_hangup(struct tty_struct *tty) { struct channel *ch; + struct tty_port *port; + /* * verifyChannel returns the channel from the tty struct if it is * valid. This serves as a sanity check. @@ -531,18 +536,19 @@ static void pc_hangup(struct tty_struct *tty) ch = verifyChannel(tty); if (ch != NULL) { unsigned long flags; + port = &ch->port; pc_flush_buffer(tty); tty_ldisc_flush(tty); - shutdown(ch); - - spin_lock_irqsave(&epca_lock, flags); - ch->port.tty = NULL; - ch->event = 0; - ch->port.count = 0; - ch->port.flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED); - spin_unlock_irqrestore(&epca_lock, flags); - wake_up_interruptible(&ch->port.open_wait); + shutdown(ch, tty); + + spin_lock_irqsave(&port->lock, flags); + port->tty = NULL; + ch->event = 0; /* FIXME: review locking of ch->event */ + port->count = 0; + port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED); + spin_unlock_irqrestore(&port->lock, flags); + wake_up_interruptible(&port->open_wait); } } @@ -792,9 +798,10 @@ static int block_til_ready(struct tty_struct *tty, DECLARE_WAITQUEUE(wait, current); int retval, do_clocal = 0; unsigned long flags; + struct tty_port *port = &ch->port; if (tty_hung_up_p(filp)) { - if (ch->port.flags & ASYNC_HUP_NOTIFY) + if (port->flags & ASYNC_HUP_NOTIFY) retval = -EAGAIN; else retval = -ERESTARTSYS; @@ -805,10 +812,10 @@ static int block_til_ready(struct tty_struct *tty, * If the device is in the middle of being closed, then block until * it's done, and then try again. */ - if (ch->port.flags & ASYNC_CLOSING) { - interruptible_sleep_on(&ch->port.close_wait); + if (port->flags & ASYNC_CLOSING) { + interruptible_sleep_on(&port->close_wait); - if (ch->port.flags & ASYNC_HUP_NOTIFY) + if (port->flags & ASYNC_HUP_NOTIFY) return -EAGAIN; else return -ERESTARTSYS; @@ -819,7 +826,7 @@ static int block_til_ready(struct tty_struct *tty, * If non-blocking mode is set, then make the check up front * and then exit. */ - ch->port.flags |= ASYNC_NORMAL_ACTIVE; + port->flags |= ASYNC_NORMAL_ACTIVE; return 0; } if (tty->termios->c_cflag & CLOCAL) @@ -827,31 +834,31 @@ static int block_til_ready(struct tty_struct *tty, /* Block waiting for the carrier detect and the line to become free */ retval = 0; - add_wait_queue(&ch->port.open_wait, &wait); + add_wait_queue(&port->open_wait, &wait); - spin_lock_irqsave(&epca_lock, flags); + spin_lock_irqsave(&port->lock, flags); /* We dec count so that pc_close will know when to free things */ if (!tty_hung_up_p(filp)) - ch->port.count--; - ch->port.blocked_open++; + port->count--; + port->blocked_open++; while (1) { set_current_state(TASK_INTERRUPTIBLE); if (tty_hung_up_p(filp) || - !(ch->port.flags & ASYNC_INITIALIZED)) { - if (ch->port.flags & ASYNC_HUP_NOTIFY) + !(port->flags & ASYNC_INITIALIZED)) { + if (port->flags & ASYNC_HUP_NOTIFY) retval = -EAGAIN; else retval = -ERESTARTSYS; break; } - if (!(ch->port.flags & ASYNC_CLOSING) && + if (!(port->flags & ASYNC_CLOSING) && (do_clocal || (ch->imodem & ch->dcd))) break; if (signal_pending(current)) { retval = -ERESTARTSYS; break; } - spin_unlock_irqrestore(&epca_lock, flags); + spin_unlock_irqrestore(&port->lock, flags); /* * Allow someone else to be scheduled. We will occasionally go * through this loop until one of the above conditions change. @@ -859,27 +866,28 @@ static int block_til_ready(struct tty_struct *tty, * and prevent this loop from hogging the cpu. */ schedule(); - spin_lock_irqsave(&epca_lock, flags); + spin_lock_irqsave(&port->lock, flags); } __set_current_state(TASK_RUNNING); - remove_wait_queue(&ch->port.open_wait, &wait); + remove_wait_queue(&port->open_wait, &wait); if (!tty_hung_up_p(filp)) - ch->port.count++; - ch->port.blocked_open--; + port->count++; + port->blocked_open--; - spin_unlock_irqrestore(&epca_lock, flags); + spin_unlock_irqrestore(&port->lock, flags); if (retval) return retval; - ch->port.flags |= ASYNC_NORMAL_ACTIVE; + port->flags |= ASYNC_NORMAL_ACTIVE; return 0; } static int pc_open(struct tty_struct *tty, struct file *filp) { struct channel *ch; + struct tty_port *port; unsigned long flags; int line, retval, boardnum; struct board_chan __iomem *bc; @@ -890,6 +898,7 @@ static int pc_open(struct tty_struct *tty, struct file *filp) return -ENODEV; ch = &digi_channels[line]; + port = &ch->port; boardnum = ch->boardnum; /* Check status of board configured in system. */ @@ -926,22 +935,24 @@ static int pc_open(struct tty_struct *tty, struct file *filp) return -ENODEV; } - spin_lock_irqsave(&epca_lock, flags); + spin_lock_irqsave(&port->lock, flags); /* * Every time a channel is opened, increment a counter. This is * necessary because we do not wish to flush and shutdown the channel * until the last app holding the channel open, closes it. */ - ch->port.count++; + port->count++; /* * Set a kernel structures pointer to our local channel structure. This * way we can get to it when passed only a tty struct. */ tty->driver_data = ch; + port->tty = tty; /* * If this is the first time the channel has been opened, initialize * the tty->termios struct otherwise let pc_close handle it. */ + spin_lock(&epca_lock); globalwinon(ch); ch->statusflags = 0; @@ -956,16 +967,16 @@ static int pc_open(struct tty_struct *tty, struct file *filp) writew(head, &bc->rout); /* Set the channels associated tty structure */ - ch->port.tty = tty; /* * The below routine generally sets up parity, baud, flow control * issues, etc.... It effect both control flags and input flags. */ epcaparam(tty, ch); - ch->port.flags |= ASYNC_INITIALIZED; memoff(ch); - spin_unlock_irqrestore(&epca_lock, flags); + spin_unlock(&epca_lock); + port->flags |= ASYNC_INITIALIZED; + spin_unlock_irqrestore(&port->lock, flags); retval = block_til_ready(tty, filp, ch); if (retval) @@ -974,13 +985,15 @@ static int pc_open(struct tty_struct *tty, struct file *filp) * Set this again in case a hangup set it to zero while this open() was * waiting for the line... */ - spin_lock_irqsave(&epca_lock, flags); - ch->port.tty = tty; + spin_lock_irqsave(&port->lock, flags); + port->tty = tty; + spin_lock(&epca_lock); globalwinon(ch); /* Enable Digi Data events */ writeb(1, &bc->idata); memoff(ch); - spin_unlock_irqrestore(&epca_lock, flags); + spin_unlock(&epca_lock); + spin_unlock_irqrestore(&port->lock, flags); return 0; } |