pty: Don't claim slave's ctrl_lock for master's packet mode

[firefly-linux-kernel-4.4.55.git] / drivers / tty / pty.c

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 29b5eeb018560e6f763cd68a6d28e987d5bcebcd..e554393d5551192997dc1048194b76bcc70b62e4 100644 (file)
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -339,26 +339,26 @@ static void pty_start(struct tty_struct *tty)
 {
        unsigned long flags;
 
-       spin_lock_irqsave(&tty->ctrl_lock, flags);
        if (tty->link && tty->link->packet) {
+               spin_lock_irqsave(&tty->ctrl_lock, flags);
                tty->ctrl_status &= ~TIOCPKT_STOP;
                tty->ctrl_status |= TIOCPKT_START;
+               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
                wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
        }
-       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 }
 
 static void pty_stop(struct tty_struct *tty)
 {
        unsigned long flags;
 
-       spin_lock_irqsave(&tty->ctrl_lock, flags);
        if (tty->link && tty->link->packet) {
+               spin_lock_irqsave(&tty->ctrl_lock, flags);
                tty->ctrl_status &= ~TIOCPKT_START;
                tty->ctrl_status |= TIOCPKT_STOP;
+               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
                wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
        }
-       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 }
 
 /**