USB: serial: quatech2: use irqsave() in USB's complete callback

The USB completion callback does not disable interrupts while acquiring
the lock. We want to remove the local_irq_disable() invocation from
__usb_hcd_giveback_urb() and therefore it is required for the callback
handler to disable the interrupts while acquiring the lock.
The callback may be invoked either in IRQ or BH context depending on the
USB host controller.
Use the _irqsave() variant of the locking primitives.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c
index ff2322ea5e1498f125b7037a59d9e937c3807a9f..b61c2a9b6b1112baf2bb4a118028cf9d50a4fc60 100644 (file)
--- a/drivers/usb/serial/quatech2.c
+++ b/drivers/usb/serial/quatech2.c
@@ -621,16 +621,17 @@ static void qt2_write_bulk_callback(struct urb *urb)
 {
        struct usb_serial_port *port;
        struct qt2_port_private *port_priv;
+       unsigned long flags;
 
        port = urb->context;
        port_priv = usb_get_serial_port_data(port);
 
-       spin_lock(&port_priv->urb_lock);
+       spin_lock_irqsave(&port_priv->urb_lock, flags);
 
        port_priv->urb_in_use = false;
        usb_serial_port_softint(port);
 
-       spin_unlock(&port_priv->urb_lock);
+       spin_unlock_irqrestore(&port_priv->urb_lock, flags);
 
 }