staging: gdm72xx: Fix spinlock recursion on gdm_usb_send_complete

This patch fixes a spinlock recursion bug on several call sites of
gdm_usb_send_complete by not calling spin_lock_irqsave on
urb->context->tx_cxt->lock when the lock has already been acquired.

Signed-off-by: Ben Chan <[e-mail]>
Cc: Sage Ahn <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/gdm72xx/gdm_usb.c

···
 	}
 }
 
-static void gdm_usb_send_complete(struct urb *urb)
+static void gdm_usb_send_complete_impl(struct urb *urb, bool need_lock)
 {
 	struct usb_tx *t = urb->context;
 	struct tx_cxt *tx = t->tx_cxt;
···
 	if (urb->status == -ECONNRESET)
 		return;
 
-	spin_lock_irqsave(&tx->lock, flags);
+	if (need_lock)
+		spin_lock_irqsave(&tx->lock, flags);
 
 	if (t->callback)
 		t->callback(t->cb_data);
···
 	else
 		free_tx_struct(t);
 
-	spin_unlock_irqrestore(&tx->lock, flags);
+	if (need_lock)
+		spin_unlock_irqrestore(&tx->lock, flags);
+}
+
+static void gdm_usb_send_complete(struct urb *urb)
+{
+	gdm_usb_send_complete_impl(urb, true);
+}
+
+static void gdm_usb_send_complete_no_lock(struct urb *urb)
+{
+	gdm_usb_send_complete_impl(urb, false);
 }
 
 static int gdm_usb_send(void *priv_dev, void *data, int len,
···
 
 send_fail:
 	t->callback = NULL;
-	gdm_usb_send_complete(t->urb);
+	gdm_usb_send_complete_no_lock(t->urb);
 	spin_unlock_irqrestore(&tx->lock, flags);
 	return ret;
 }
···
 
 			if (ret) {
 				t->callback = NULL;
-				gdm_usb_send_complete(t->urb);
+				gdm_usb_send_complete_no_lock(t->urb);
 			}
 		}
 	}
···
 
 				if (ret) {
 					t->callback = NULL;
-					gdm_usb_send_complete(t->urb);
+					gdm_usb_send_complete_no_lock(t->urb);
 				}
 			}