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From arnd@arndb.de Wed Jun 16 13:36:19 2010
From: Alan Cox <alan@linux.intel.com>
Date: Tue, 1 Jun 2010 22:52:59 +0200
Subject: serial: trim locking on the helpers
To: Greg KH <gregkh@suse.de>
Cc: linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>, Alan Cox <alan@lxorguk.ukuu.org.uk>, Frederic Weisbecker <fweisbec@gmail.com>, John Kacur <jkacur@redhat.com>, Alan Cox <alan@linux.intel.com>
Message-ID: <1275425591-8803-20-git-send-email-arnd@arndb.de>
From: Alan Cox <alan@linux.intel.com>
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>
---
drivers/serial/serial_core.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1506,12 +1506,10 @@ static int uart_carrier_raised(struct tt
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
{
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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