From: Claudio Scordino <claudio@evidence.eu.com>
Date: Fri, 16 Dec 2011 14:08:49 +0000 (+0100)
Subject: atmel_serial: fix spinlock lockup in RS485 code
X-Git-Tag: v3.1.9~24
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cf2f03e57c607a7863e6010ca9e5c4d08bc5b48c;p=thirdparty%2Fkernel%2Fstable.git

atmel_serial: fix spinlock lockup in RS485 code

commit dbf1115d3f8c7052788aa4e6e46abd27f3b3eeba upstream.

Patch to fix a spinlock lockup in the driver that sometimes happens when the
tasklet starts.

Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Signed-off-by: Dave Bender <codehero@gmail.com>
Tested-by: Dave Bender <codehero@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index b922f5d2e61e0..948fc77b647a1 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -199,8 +199,9 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	unsigned int mode;
+	unsigned long flags;
 
-	spin_lock(&port->lock);
+	spin_lock_irqsave(&port->lock, flags);
 
 	/* Disable interrupts */
 	UART_PUT_IDR(port, atmel_port->tx_done_mask);
@@ -231,7 +232,7 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 	/* Enable interrupts */
 	UART_PUT_IER(port, atmel_port->tx_done_mask);
 
-	spin_unlock(&port->lock);
+	spin_unlock_irqrestore(&port->lock, flags);
 
 }