[PATCH V7 04/11] USB: f81232: change lock mechanism

Peter Hung
2015-02-24T10:18:52Z

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>
---
drivers/usb/serial/f81232.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 419e2d6..bf072fe 100644
--- 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>
@@ -51,7 +51,7 @@ 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;
};
@@ -306,17 +306,16 @@ 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);
}

@@ -360,7 +359,7 @@ 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);

--
1.9.1