usb: gadget: pch_udc: Revert d3cb25a1 completely

The commit d3cb25a1 ("usb: gadget: udc: fix spin_lock in pch_udc")
obviously was not thought through and had made the situation even worse
than it was before. Two changes after almost reverted it. but a few
leftovers have been left as it. With this revert d3cb25a1 completely.

While at it, narrow down the scope of unlocked section to prevent
potential race when prot_stall is assigned.

Fixes: d3cb25a1 ("usb: gadget: udc: fix spin_lock in pch_udc")
Fixes: 9903b6be ("usb: gadget: pch-udc: fix lock")
Fixes: 1d23d16a ("usb: gadget: pch_udc: reorder spin_[un]lock to avoid deadlock")
Cc: Iago Abal <mail@iagoabal.eu>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210323153626.54908-5-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/pch_udc.c

@@ -597,18 +597,22 @@ static void pch_udc_reconnect(struct pch_udc_dev *dev)
 static inline void pch_udc_vbus_session(struct pch_udc_dev *dev,
 					  int is_active)
 {
+	unsigned long		iflags;
+
+	spin_lock_irqsave(&dev->lock, iflags);
 	if (is_active) {
 		pch_udc_reconnect(dev);
 		dev->vbus_session = 1;
 	} else {
 		if (dev->driver && dev->driver->disconnect) {
-			spin_lock(&dev->lock);
+			spin_unlock_irqrestore(&dev->lock, iflags);
 			dev->driver->disconnect(&dev->gadget);
-			spin_unlock(&dev->lock);
+			spin_lock_irqsave(&dev->lock, iflags);
 		}
 		pch_udc_set_disconnect(dev);
 		dev->vbus_session = 0;
 	}
+	spin_unlock_irqrestore(&dev->lock, iflags);
 }
 
 /**
@@ -1167,20 +1171,25 @@ static int pch_udc_pcd_selfpowered(struct usb_gadget *gadget, int value)
 static int pch_udc_pcd_pullup(struct usb_gadget *gadget, int is_on)
 {
 	struct pch_udc_dev	*dev;
+	unsigned long		iflags;
 
 	if (!gadget)
 		return -EINVAL;
+
 	dev = container_of(gadget, struct pch_udc_dev, gadget);
+
+	spin_lock_irqsave(&dev->lock, iflags);
 	if (is_on) {
 		pch_udc_reconnect(dev);
 	} else {
 		if (dev->driver && dev->driver->disconnect) {
-			spin_lock(&dev->lock);
+			spin_unlock_irqrestore(&dev->lock, iflags);
 			dev->driver->disconnect(&dev->gadget);
-			spin_unlock(&dev->lock);
+			spin_lock_irqsave(&dev->lock, iflags);
 		}
 		pch_udc_set_disconnect(dev);
 	}
+	spin_unlock_irqrestore(&dev->lock, iflags);
 
 	return 0;
 }