USB: f81232: change lock mechanism

The original driver lock with spin_lock_irqsave()/spin_unlock_irqrestore()
because of it's maybe used in interrupt context f81232_process_read_urb().

We had remove it from previous patch "implement RX bulk-in EP", so we can
change it from busying loop spin_lock to sleepable mutex_lock.

Signed-off-by: Peter Hung <hpeter+linux_kernel@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 4664cf4cc7a8fdf81f752d8cf62d37cbfddf7334..12840cdc8532e7462973db462d7acb170a1adf2f 100644 (file)
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -19,7 +19,7 @@
 #include <linux/serial.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
-#include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/uaccess.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
@@ -46,7 +46,7 @@ MODULE_DEVICE_TABLE(usb, id_table);
 #define UART_CTS                       0x80
 
 struct f81232_private {
-       spinlock_t lock;
+       struct mutex lock;
        u8 line_control;
        u8 modem_status;
 };
@@ -231,17 +231,16 @@ static void f81232_close(struct usb_serial_port *port)
 static void f81232_dtr_rts(struct usb_serial_port *port, int on)
 {
        struct f81232_private *priv = usb_get_serial_port_data(port);
-       unsigned long flags;
        u8 control;
 
-       spin_lock_irqsave(&priv->lock, flags);
+       mutex_lock(&priv->lock);
        /* Change DTR and RTS */
        if (on)
                priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
        else
                priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
        control = priv->line_control;
-       spin_unlock_irqrestore(&priv->lock, flags);
+       mutex_unlock(&priv->lock);
        set_control_lines(port->serial->dev, control);
 }
 
@@ -285,7 +284,7 @@ static int f81232_port_probe(struct usb_serial_port *port)
        if (!priv)
                return -ENOMEM;
 
-       spin_lock_init(&priv->lock);
+       mutex_init(&priv->lock);
 
        usb_set_serial_port_data(port, priv);