From: Yegor Yefremov <yegorslists@googlemail.com>
Date: Fri, 29 Apr 2016 08:45:07 +0000 (+0200)
Subject: serial: mctrl_gpio: add IRQ locking
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d11df61853f1d45035b7f5a6702c9b48d5f09a49;p=linux-beck.git

serial: mctrl_gpio: add IRQ locking

uart_handle_cts_change should be called with port->lock held. And for
this to be save you must also disable irqs.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
index 02147361eaa9..9e1086f7f22a 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.c
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -125,9 +125,12 @@ static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
 	struct uart_port *port = gpios->port;
 	u32 mctrl = gpios->mctrl_prev;
 	u32 mctrl_diff;
+	unsigned long flags;
 
 	mctrl_gpio_get(gpios, &mctrl);
 
+	spin_lock_irqsave(&port->lock, flags);
+
 	mctrl_diff = mctrl ^ gpios->mctrl_prev;
 	gpios->mctrl_prev = mctrl;
 
@@ -147,6 +150,8 @@ static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
 		wake_up_interruptible(&port->state->port.delta_msr_wait);
 	}
 
+	spin_unlock_irqrestore(&port->lock, flags);
+
 	return IRQ_HANDLED;
 }