tty: Replace ASYNC_NORMAL_ACTIVE bit and update atomically

Replace ASYNC_NORMAL_ACTIVE bit in the tty_port::flags field with
TTY_PORT_ACTIVE bit in the tty_port::iflags field. Introduce helpers
tty_port_set_active() and tty_port_active() to abstract atomic bit ops.

Extract state changes from port lock sections, as this usage is
broken and confused; the state transitions are protected by the
tty lock (which mutually excludes parallel open/close/hangup),
and no user tests the active state while holding the port lock.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

8 files changed, 27 insertions, 26 deletions

diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index 92717b088959..80d61658efb0 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -1493,7 +1493,7 @@ static void rs_hangup(struct tty_struct *tty)
 	rs_flush_buffer(tty);
 	shutdown(tty, info);
 	info->tport.count = 0;
-	info->tport.flags &= ~ASYNC_NORMAL_ACTIVE;
+	tty_port_set_active(&info->tport, 0);
 	info->tport.tty = NULL;
 	wake_up_interruptible(&info->tport.open_wait);
 }
diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
index 0b802cdd70d0..eb8311b20782 100644
--- a/drivers/tty/rocket.c
+++ b/drivers/tty/rocket.c
@@ -1042,9 +1042,10 @@ static void rp_close(struct tty_struct *tty, struct file *filp)
 		}
 	}
 	spin_lock_irq(&port->lock);
-	info->port.flags &= ~(ASYNC_INITIALIZED | ASYNC_NORMAL_ACTIVE);
+	port->flags &= ~ASYNC_INITIALIZED;
 	tty->closing = 0;
 	spin_unlock_irq(&port->lock);
+	tty_port_set_active(port, 0);
 	mutex_unlock(&port->mutex);
 	tty_port_tty_set(port, NULL);
 
@@ -1624,7 +1625,7 @@ static int rp_write(struct tty_struct *tty,
 	/*  Write remaining data into the port's xmit_buf */
 	while (1) {
 		/* Hung up ? */
-		if (!test_bit(ASYNCB_NORMAL_ACTIVE, &info->port.flags))
+		if (!tty_port_active(&info->port))
 			goto end;
 		c = min(count, XMIT_BUF_SIZE - info->xmit_cnt - 1);
 		c = min(c, XMIT_BUF_SIZE - info->xmit_head);
diff --git a/drivers/tty/serial/crisv10.c b/drivers/tty/serial/crisv10.c
index 546990334815..92c8c628e00e 100644
--- a/drivers/tty/serial/crisv10.c
+++ b/drivers/tty/serial/crisv10.c
@@ -3648,8 +3648,8 @@ rs_close(struct tty_struct *tty, struct file * filp)
 			schedule_timeout_interruptible(info->port.close_delay);
 		wake_up_interruptible(&info->port.open_wait);
 	}
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
 	local_irq_restore(flags);
+	tty_port_set_active(&info->port, 0);
 
 	/* port closed */
 
@@ -3732,7 +3732,7 @@ rs_hangup(struct tty_struct *tty)
 	shutdown(info);
 	info->event = 0;
 	info->port.count = 0;
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
+	tty_port_set_active(&info->port, 0);
 	info->port.tty = NULL;
 	wake_up_interruptible(&info->port.open_wait);
 }
@@ -3756,7 +3756,7 @@ block_til_ready(struct tty_struct *tty, struct file * filp,
 	 * then make the check up front and then exit.
 	 */
 	if ((filp->f_flags & O_NONBLOCK) || tty_io_error(tty)) {
-		info->port.flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(&info->port, 1);
 		return 0;
 	}
 
@@ -3825,7 +3825,7 @@ block_til_ready(struct tty_struct *tty, struct file * filp,
 #endif
 	if (retval)
 		return retval;
-	info->port.flags |= ASYNC_NORMAL_ACTIVE;
+	tty_port_set_active(&info->port, 1);
 	return 0;
 }
 
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 64a5c00d7468..2471380fb92e 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1418,12 +1418,12 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
 		uart_change_pm(state, UART_PM_STATE_OFF);
 		spin_lock_irq(&port->lock);
 	}
+	spin_unlock_irq(&port->lock);
+	tty_port_set_active(port, 0);
 
 	/*
 	 * Wake up anyone trying to open this port.
 	 */
-	clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
-	spin_unlock_irq(&port->lock);
 	wake_up_interruptible(&port->open_wait);
 
 	mutex_unlock(&port->mutex);
@@ -1501,13 +1501,13 @@ static void uart_hangup(struct tty_struct *tty)
 	pr_debug("uart_hangup(%d)\n", tty->index);
 
 	mutex_lock(&port->mutex);
-	if (port->flags & ASYNC_NORMAL_ACTIVE) {
+	if (tty_port_active(port)) {
 		uart_flush_buffer(tty);
 		uart_shutdown(tty, state);
 		spin_lock_irqsave(&port->lock, flags);
 		port->count = 0;
-		clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
 		spin_unlock_irqrestore(&port->lock, flags);
+		tty_port_set_active(port, 0);
 		tty_port_tty_set(port, NULL);
 		if (!uart_console(state->uart_port))
 			uart_change_pm(state, UART_PM_STATE_OFF);
diff --git a/drivers/tty/synclink.c b/drivers/tty/synclink.c
index 0e4290183280..b55f8468cde5 100644
--- a/drivers/tty/synclink.c
+++ b/drivers/tty/synclink.c
@@ -3201,7 +3201,7 @@ static void mgsl_hangup(struct tty_struct *tty)
 	shutdown(info);
 	
 	info->port.count = 0;	
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
+	tty_port_set_active(&info->port, 0);
 	info->port.tty = NULL;
 
 	wake_up_interruptible(&info->port.open_wait);
@@ -3269,7 +3269,7 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
 
 	if (filp->f_flags & O_NONBLOCK || tty_io_error(tty)) {
 		/* nonblock mode is set or port is not enabled */
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 
@@ -3338,7 +3338,7 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
 			 __FILE__,__LINE__, tty->driver->name, port->count );
 			 
 	if (!retval)
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		
 	return retval;
 	
diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index 5da69d30f816..c76f546697dc 100644
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -756,9 +756,9 @@ static void hangup(struct tty_struct *tty)
 
 	spin_lock_irqsave(&info->port.lock, flags);
 	info->port.count = 0;
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
 	info->port.tty = NULL;
 	spin_unlock_irqrestore(&info->port.lock, flags);
+	tty_port_set_active(&info->port, 0);
 	mutex_unlock(&info->port.mutex);
 
 	wake_up_interruptible(&info->port.open_wait);
@@ -3268,7 +3268,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 
 	if (filp->f_flags & O_NONBLOCK || tty_io_error(tty)) {
 		/* nonblock mode is set or port is not enabled */
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 
@@ -3325,7 +3325,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 	port->blocked_open--;
 
 	if (!retval)
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 
 	DBGINFO(("%s block_til_ready ready, rc=%d\n", tty->driver->name, retval));
 	return retval;
diff --git a/drivers/tty/synclinkmp.c b/drivers/tty/synclinkmp.c
index 7a21491d0c0d..95eddc4d9eb8 100644
--- a/drivers/tty/synclinkmp.c
+++ b/drivers/tty/synclinkmp.c
@@ -849,9 +849,9 @@ static void hangup(struct tty_struct *tty)
 
 	spin_lock_irqsave(&info->port.lock, flags);
 	info->port.count = 0;
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
 	info->port.tty = NULL;
 	spin_unlock_irqrestore(&info->port.lock, flags);
+	tty_port_set_active(&info->port, 1);
 	mutex_unlock(&info->port.mutex);
 
 	wake_up_interruptible(&info->port.open_wait);
@@ -3285,7 +3285,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 	if (filp->f_flags & O_NONBLOCK || tty_io_error(tty)) {
 		/* nonblock mode is set or port is not enabled */
 		/* just verify that callout device is not active */
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 
@@ -3352,7 +3352,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 			 __FILE__,__LINE__, tty->driver->name, port->count );
 
 	if (!retval)
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 
 	return retval;
 }
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 9127c54b803e..130c8cf520cb 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -236,12 +236,12 @@ void tty_port_hangup(struct tty_port *port)
 
 	spin_lock_irqsave(&port->lock, flags);
 	port->count = 0;
-	port->flags &= ~ASYNC_NORMAL_ACTIVE;
 	tty = port->tty;
 	if (tty)
 		set_bit(TTY_IO_ERROR, &tty->flags);
 	port->tty = NULL;
 	spin_unlock_irqrestore(&port->lock, flags);
+	tty_port_set_active(port, 0);
 	tty_port_shutdown(port, tty);
 	tty_kref_put(tty);
 	wake_up_interruptible(&port->open_wait);
@@ -365,14 +365,14 @@ int tty_port_block_til_ready(struct tty_port *port,
 	/* if non-blocking mode is set we can pass directly to open unless
 	   the port has just hung up or is in another error state */
 	if (tty_io_error(tty)) {
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 	if (filp->f_flags & O_NONBLOCK) {
 		/* Indicate we are open */
 		if (C_BAUD(tty))
 			tty_port_raise_dtr_rts(port);
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 
@@ -430,9 +430,9 @@ int tty_port_block_til_ready(struct tty_port *port,
 	if (!tty_hung_up_p(filp))
 		port->count++;
 	port->blocked_open--;
-	if (retval == 0)
-		port->flags |= ASYNC_NORMAL_ACTIVE;
 	spin_unlock_irqrestore(&port->lock, flags);
+	if (retval == 0)
+		tty_port_set_active(port, 1);
 	return retval;
 }
 EXPORT_SYMBOL(tty_port_block_til_ready);
@@ -514,8 +514,8 @@ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
 		spin_lock_irqsave(&port->lock, flags);
 		wake_up_interruptible(&port->open_wait);
 	}
-	port->flags &= ~ASYNC_NORMAL_ACTIVE;
 	spin_unlock_irqrestore(&port->lock, flags);
+	tty_port_set_active(port, 0);
 }
 EXPORT_SYMBOL(tty_port_close_end);