--- zzzz-none-000/linux-3.10.107/drivers/xen/xen-pciback/xenbus.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/xen/xen-pciback/xenbus.c	2021-02-04 17:41:59.000000000 +0000
@@ -3,6 +3,9 @@
  *
  *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
  */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/list.h>
@@ -41,7 +44,6 @@
 	dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);
 
 	pdev->xdev = xdev;
-	dev_set_drvdata(&xdev->dev, pdev);
 
 	mutex_init(&pdev->dev_lock);
 
@@ -55,6 +57,9 @@
 		kfree(pdev);
 		pdev = NULL;
 	}
+
+	dev_set_drvdata(&xdev->dev, pdev);
+
 out:
 	return pdev;
 }
@@ -90,6 +95,8 @@
 
 	xen_pcibk_disconnect(pdev);
 
+	/* N.B. This calls pcistub_put_pci_dev which does the FLR on all
+	 * of the PCIe devices. */
 	xen_pcibk_release_devices(pdev);
 
 	dev_set_drvdata(&pdev->xdev->dev, NULL);
@@ -108,7 +115,7 @@
 		"Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
 		gnt_ref, remote_evtchn);
 
-	err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
+	err = xenbus_map_ring_valloc(pdev->xdev, &gnt_ref, 1, &vaddr);
 	if (err < 0) {
 		xenbus_dev_fatal(pdev->xdev, err,
 				"Error mapping other domain page in ours.");
@@ -169,6 +176,7 @@
 				 "version mismatch (%s/%s) with pcifront - "
 				 "halting " DRV_NAME,
 				 magic, XEN_PCI_MAGIC);
+		err = -EFAULT;
 		goto out;
 	}
 
@@ -241,7 +249,7 @@
 	if (err)
 		goto out;
 
-	dev_dbg(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
+	dev_info(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
 	if (xen_register_device_domain_owner(dev,
 					     pdev->xdev->otherend_id) != 0) {
 		dev_err(&dev->dev, "Stealing ownership from dom%d.\n",
@@ -283,7 +291,9 @@
 	dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
 	xen_unregister_device_domain_owner(dev);
 
-	xen_pcibk_release_pci_dev(pdev, dev);
+	/* N.B. This ends up calling pcistub_put_pci_dev which ends up
+	 * doing the FLR. */
+	xen_pcibk_release_pci_dev(pdev, dev, true /* use the lock. */);
 
 out:
 	return err;
@@ -711,11 +721,13 @@
 	{""},
 };
 
-static DEFINE_XENBUS_DRIVER(xen_pcibk, DRV_NAME,
+static struct xenbus_driver xen_pcibk_driver = {
+	.name                   = DRV_NAME,
+	.ids                    = xen_pcibk_ids,
 	.probe			= xen_pcibk_xenbus_probe,
 	.remove			= xen_pcibk_xenbus_remove,
 	.otherend_changed	= xen_pcibk_frontend_changed,
-);
+};
 
 const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
 
@@ -723,14 +735,13 @@
 {
 	xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
 	if (!xen_pcibk_wq) {
-		printk(KERN_ERR "%s: create"
-			"xen_pciback_workqueue failed\n", __func__);
+		pr_err("%s: create xen_pciback_workqueue failed\n", __func__);
 		return -EFAULT;
 	}
 	xen_pcibk_backend = &xen_pcibk_vpci_backend;
 	if (passthrough)
 		xen_pcibk_backend = &xen_pcibk_passthrough_backend;
-	pr_info(DRV_NAME ": backend is %s\n", xen_pcibk_backend->name);
+	pr_info("backend is %s\n", xen_pcibk_backend->name);
 	return xenbus_register_backend(&xen_pcibk_driver);
 }