serial: trim locking on the helpers

The port mutex protects port->tty, but these paths never need to walk from
port->tty. They do need the low level lock as the API expects that but they
already also take it.

Thus we can drop the extra mutex lock calls here.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 1 insertions, 4 deletions

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 2379045e0871..0603e0d46d33 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1506,12 +1506,10 @@ static int uart_carrier_raised(struct tty_port *port)
         struct uart_state *state = container_of(port, struct uart_state, port);
         struct uart_port *uport = state->uart_port;
         int mctrl;
-        mutex_lock(&port->mutex);
         spin_lock_irq(&uport->lock);
         uport->ops->enable_ms(uport);
         mctrl = uport->ops->get_mctrl(uport);
         spin_unlock_irq(&uport->lock);
-        mutex_unlock(&port->mutex);
         if (mctrl & TIOCM_CAR)
                 return 1;
         return 0;
@@ -1521,12 +1519,11 @@ static void uart_dtr_rts(struct tty_port *port, int onoff)
 {
         struct uart_state *state = container_of(port, struct uart_state, port);
         struct uart_port *uport = state->uart_port;
-        mutex_lock(&port->mutex);
+
         if (onoff)
                 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
         else
                 uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
-        mutex_unlock(&port->mutex);
 }
 
 /*