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From: Alan Cox on 5 May 2010 06:50
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(a)linux.intel.com>
---

drivers/serial/serial_core.c | 5 +----
1 files changed, 1 insertions(+), 4 deletions(-)


diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 2379045..0603e0d 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);
}

/*

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