serial: core: Remove unsafe x_char optimization

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

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 0742f77ac4104e98b29e8d9ab9a50cda9054bf97..bdc543caf069a6f4a4d1dfa18f7309d44f15e02b 100644 (file)
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -600,12 +600,11 @@ static void uart_send_xchar(struct tty_struct *tty, char ch)
        if (port->ops->send_xchar)
                port->ops->send_xchar(port, ch);
        else {
+               spin_lock_irqsave(&port->lock, flags);
                port->x_char = ch;
-               if (ch) {
-                       spin_lock_irqsave(&port->lock, flags);
+               if (ch)
                        port->ops->start_tx(port);
-                       spin_unlock_irqrestore(&port->lock, flags);
-               }
+               spin_unlock_irqrestore(&port->lock, flags);
        }
 }
 
@@ -648,12 +647,8 @@ static void uart_unthrottle(struct tty_struct *tty)
                mask &= ~port->flags;
        }
 
-       if (mask & UPF_SOFT_FLOW) {
-               if (port->x_char)
-                       port->x_char = 0;
-               else
-                       uart_send_xchar(tty, START_CHAR(tty));
-       }
+       if (mask & UPF_SOFT_FLOW)
+               uart_send_xchar(tty, START_CHAR(tty));
 
        if (mask & UPF_HARD_FLOW)
                uart_set_mctrl(port, TIOCM_RTS);