Commit d1c815e5 authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
Browse files

tty: relock epca 



Bring epca into line with the port locking.

Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 542f5482

drivers/char/epca.c

+104 −91
Original line number Diff line number Diff line
@@ -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 *);
@@ -419,41 +421,45 @@ 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 (ch == NULL)

		return;

	port = &ch->port;



	spin_lock_irqsave(&port->lock, flags);

	if (tty_hung_up_p(filp)) {

			spin_unlock_irqrestore(&epca_lock, flags);

		spin_unlock_irqrestore(&port->lock, flags);

		return;

	}

		if (ch->port.count-- > 1)  {

	if (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);

		spin_unlock_irqrestore(&port->lock, flags);

		return;

	}

	/* Port open only once go ahead with shutdown & reset */

		BUG_ON(ch->port.count < 0);

	WARN_ON(port->count < 0);



	/*

	 * Let the rest of the driver know the channel is being closed.

	 * This becomes important if an open is attempted before close

	 * is finished.

	 */

		ch->port.flags |= ASYNC_CLOSING;

	port->flags |= ASYNC_CLOSING;

	tty->closing = 1;



		spin_unlock_irqrestore(&epca_lock, flags);

	spin_unlock_irqrestore(&port->lock, flags);



		if (ch->port.flags & ASYNC_INITIALIZED)  {

	if (port->flags & ASYNC_INITIALIZED)  {

		/* Setup an event to indicate when the

		   transmit buffer empties */

		setup_empty_event(tty, ch);
@@ -461,34 +467,32 @@ static void pc_close(struct tty_struct *tty, struct file *filp) 
		tty_wait_until_sent(tty, 3000);

	}

	pc_flush_buffer(tty);



	tty_ldisc_flush(tty);

		shutdown(ch);

	shutdown(ch, tty);



		spin_lock_irqsave(&epca_lock, flags);

	spin_lock_irqsave(&port->lock, flags);

	tty->closing = 0;

	ch->event = 0;

		ch->port.tty = NULL;

		spin_unlock_irqrestore(&epca_lock, flags);

	port->tty = NULL;

	spin_unlock_irqrestore(&port->lock, flags);



		if (ch->port.blocked_open) {

	if (port->blocked_open) {

		if (ch->close_delay)

			msleep_interruptible(jiffies_to_msecs(ch->close_delay));

			wake_up_interruptible(&ch->port.open_wait);

		wake_up_interruptible(&port->open_wait);

	}

		ch->port.flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED |

	port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED |

							ASYNC_CLOSING);

		wake_up_interruptible(&ch->port.close_wait);

	}

	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);

		shutdown(ch, tty);



		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);

		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;

}