CA-87824-reorder-netback-closing-opening.patch

# HG changeset patch
# Parent 41f82ccc206109d3c9bed0c6468873b1646b009c
CA-87824: Reorder the opening and closing for the netback sysfs interfaces in order to minimise the chances of being able to access a NULL sysfs entry.

diff -r 41f82ccc2061 drivers/xen/netback/xenbus.c
--- a/drivers/xen/netback/xenbus.c
+++ b/drivers/xen/netback/xenbus.c
@@ -48,11 +48,10 @@ static int netback_remove(struct xenbus_
 
 	netback_remove_accelerators(be, dev);
 
-	netif_sysfs_delif(dev);
 	unregister_hotplug_status_watch(be);
 	disconnect_backend(be);
+	dev_set_drvdata(&dev->dev, NULL);
 	kfree(be);
-	dev_set_drvdata(&dev->dev, NULL);
 	return 0;
 }
 
@@ -78,12 +77,6 @@ static int netback_probe(struct xenbus_d
 	be->dev = dev;
 	dev_set_drvdata(&dev->dev, be);
 
-	err = netif_sysfs_addif(dev);
-	if (err) {
-		xenbus_dev_fatal(dev, err, "creating sysfs entries");
-		goto fail;
-	}
-
 	sg = 1;
 	if (netbk_copy_skb_mode == NETBK_ALWAYS_COPY_SKB)
 		sg = 0;
@@ -261,6 +254,10 @@ static void backend_create_netif(struct 
 		return;
 	}
 
+	err = netif_sysfs_addif(dev);
+	if (err) {
+		dev_warn(dev, "failed to create sysfs entries");
+	}
 	kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
 }
 
@@ -271,6 +268,7 @@ static void disconnect_backend(struct ba
 
 	if (be->netif) {
 		kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
+		netif_sysfs_delif(dev);
 		unregister_gso_watch(be);
 		unregister_gso_prefix_watch(be);
 		xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");