From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: [PATCH 3/4] serial: trim locking on the helpers Date: Wed, 19 May 2010 13:14:09 +0100 Message-ID: <20100519121408.18011.34543.stgit@localhost.localdomain> References: <20100519121234.18011.51870.stgit@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:36527 "EHLO bob.linux.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758052Ab0ESM4h (ORCPT ); Wed, 19 May 2010 08:56:37 -0400 In-Reply-To: <20100519121234.18011.51870.stgit@localhost.localdomain> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: greg@kroah.com, linux-serial@vger.kernel.org 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 --- 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); } /*