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authorAmit Shah <amit.shah@redhat.com>2011-07-27 12:28:19 +0530
committerAmit Shah <amit.shah@redhat.com>2011-07-28 15:09:49 +0530
commiteaa8b2778c182c8f795970dd46fef5b039fb741c (patch)
tree07c108072533289f525d8960dea2b741ee53f20c
parentvirtio-balloon: Fix header comment; add Copyright (diff)
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balloon: Don't allow multiple balloon handler registrations
Multiple balloon devices don't make sense; disallow more than one registration attempt to register handlers. Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com>
-rw-r--r--balloon.c12
-rw-r--r--balloon.h4
2 files changed, 12 insertions, 4 deletions
diff --git a/balloon.c b/balloon.c
index a93847527..5200565cb 100644
--- a/balloon.c
+++ b/balloon.c
@@ -36,12 +36,20 @@ static QEMUBalloonEvent *balloon_event_fn;
static QEMUBalloonStatus *balloon_stat_fn;
static void *balloon_opaque;
-void qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
- QEMUBalloonStatus *stat_func, void *opaque)
+int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
+ QEMUBalloonStatus *stat_func, void *opaque)
{
+ if (balloon_event_fn || balloon_stat_fn || balloon_opaque) {
+ /* We're already registered one balloon handler. How many can
+ * a guest really have?
+ */
+ error_report("Another balloon device already registered");
+ return -1;
+ }
balloon_event_fn = event_func;
balloon_stat_fn = stat_func;
balloon_opaque = opaque;
+ return 0;
}
static int qemu_balloon(ram_addr_t target)
diff --git a/balloon.h b/balloon.h
index a6c31d587..3df14e645 100644
--- a/balloon.h
+++ b/balloon.h
@@ -20,8 +20,8 @@ typedef void (QEMUBalloonEvent)(void *opaque, ram_addr_t target);
typedef void (QEMUBalloonStatus)(void *opaque, MonitorCompletion cb,
void *cb_data);
-void qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
- QEMUBalloonStatus *stat_func, void *opaque);
+int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
+ QEMUBalloonStatus *stat_func, void *opaque);
void monitor_print_balloon(Monitor *mon, const QObject *data);
int do_info_balloon(Monitor *mon, MonitorCompletion cb, void *opaque);