[11/12] usb: serial: ti_usb_3410_5052: use irqsave() in USB's complete callback

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2018-06-23 22:32:14
Subsystem: the rest, usb serial subsystem, usb subsystem · Maintainers: Linus Torvalds, Johan Hovold, Greg Kroah-Hartman

From: John Ogness <john.ogness@linutronix.de>

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.

Cc: Johan Hovold <johan@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/usb/serial/ti_usb_3410_5052.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index 6b22857f6e52..3010878f7f8e 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -1215,6 +1215,7 @@ static void ti_bulk_in_callback(struct urb *urb)
 	struct usb_serial_port *port = tport->tp_port;
 	struct device *dev = &urb->dev->dev;
 	int status = urb->status;
+	unsigned long flags;
 	int retval = 0;
 
 	switch (status) {
@@ -1247,20 +1248,20 @@ static void ti_bulk_in_callback(struct urb *urb)
 				__func__);
 		else
 			ti_recv(port, urb->transfer_buffer, urb->actual_length);
-		spin_lock(&tport->tp_lock);
+		spin_lock_irqsave(&tport->tp_lock, flags);
 		port->icount.rx += urb->actual_length;
-		spin_unlock(&tport->tp_lock);
+		spin_unlock_irqrestore(&tport->tp_lock, flags);
 	}
 
 exit:
 	/* continue to read unless stopping */
-	spin_lock(&tport->tp_lock);
+	spin_lock_irqsave(&tport->tp_lock, flags);
 	if (tport->tp_read_urb_state == TI_READ_URB_RUNNING)
 		retval = usb_submit_urb(urb, GFP_ATOMIC);
 	else if (tport->tp_read_urb_state == TI_READ_URB_STOPPING)
 		tport->tp_read_urb_state = TI_READ_URB_STOPPED;
 
-	spin_unlock(&tport->tp_lock);
+	spin_unlock_irqrestore(&tport->tp_lock, flags);
 	if (retval)
 		dev_err(dev, "%s - resubmit read urb failed, %d\n",
 			__func__, retval);
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