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, 3 deletions

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;
 }