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>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
index 0b802cd..eb8311b 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);