[Qemu-devel] [RFC PATCH 1/3] balloon: Allow nested inhibits

[Alex Williamson <alex.williamson@redhat.com>]

A simple true/false internal state does not allow multiple users.  Fix
this within the existing interface by converting to a counter, so long
as the counter is elevated, ballooning is inhibited.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 balloon.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/balloon.c b/balloon.c
index 6bf0a9681377..2a6a7e1a22a0 100644
--- a/balloon.c
+++ b/balloon.c
@@ -37,16 +37,17 @@
 static QEMUBalloonEvent *balloon_event_fn;
 static QEMUBalloonStatus *balloon_stat_fn;
 static void *balloon_opaque;
-static bool balloon_inhibited;
+static int balloon_inhibited;
 
 bool qemu_balloon_is_inhibited(void)
 {
-    return balloon_inhibited;
+    return balloon_inhibited > 0;
 }
 
 void qemu_balloon_inhibit(bool state)
 {
-    balloon_inhibited = state;
+    balloon_inhibited += (state ? 1 : -1);
+    assert(balloon_inhibited >= 0);
 }
 
 static bool have_balloon(Error **errp)