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tty: Replace ASYNC_NORMAL_ACTIVE bit and update atomically

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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>
This commit is contained in:
Peter Hurley
2016-04-09 17:53:22 -07:00
committed by Greg Kroah-Hartman
parent 5604a98e2f
commit 807c8d81f4
11 changed files with 53 additions and 42 deletions
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6
drivers/tty/synclink_gt.c
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@@ -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;