Merge tag 'uuid-for-4.13-2' of git://git.infradead.org/users/hch/uuid

[linux.git] / drivers / xen / xen-balloon.c

diff --git a/drivers/xen/xen-balloon.c b/drivers/xen/xen-balloon.c
index e7715cb62eefc307a354a77902baaaa5916a157c..e89136ab851e30c1aff97893615f72f2d5bf3cd7 100644 (file)
--- a/drivers/xen/xen-balloon.c
+++ b/drivers/xen/xen-balloon.c
@@ -59,6 +59,8 @@ static void watch_target(struct xenbus_watch *watch,
 {
        unsigned long long new_target;
        int err;
+       static bool watch_fired;
+       static long target_diff;
 
        err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
        if (err != 1) {
@@ -69,7 +71,14 @@ static void watch_target(struct xenbus_watch *watch,
        /* The given memory/target value is in KiB, so it needs converting to
         * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
         */
-       balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
+       new_target >>= PAGE_SHIFT - 10;
+       if (watch_fired) {
+               balloon_set_new_target(new_target - target_diff);
+               return;
+       }
+
+       watch_fired = true;
+       target_diff = new_target - balloon_stats.target_pages;
 }
 static struct xenbus_watch target_watch = {
        .node = "memory/target",
@@ -94,22 +103,15 @@ static struct notifier_block xenstore_notifier = {
        .notifier_call = balloon_init_watcher,
 };
 
-static int __init balloon_init(void)
+void xen_balloon_init(void)
 {
-       if (!xen_domain())
-               return -ENODEV;
-
-       pr_info("Initialising balloon driver\n");
-
        register_balloon(&balloon_dev);
 
        register_xen_selfballooning(&balloon_dev);
 
        register_xenstore_notifier(&xenstore_notifier);
-
-       return 0;
 }
-subsys_initcall(balloon_init);
+EXPORT_SYMBOL_GPL(xen_balloon_init);
 
 #define BALLOON_SHOW(name, format, args...)                            \
        static ssize_t show_##name(struct device *dev,                  \