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>

2 files changed, 8 insertions, 8 deletions

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);