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authorStefan Hajnoczi <stefanha@redhat.com>2013-06-24 17:13:09 +0200
committerKevin Wolf <kwolf@redhat.com>2013-06-28 09:20:26 +0200
commit5dae8e5fb803f53fadc116cefe353953b938cbe1 (patch)
tree65f12d6da71012da6e771a0c2d6c4bb0c9df7d43 /util/notify.c
parenta5c5ea3f60c000bf18c99435439533728a5f34a2 (diff)
notify: add NotiferWithReturn so notifier list can abort
notifier_list_notify() has no return value. This is fine when we just want to invoke side-effects. Sometimes it's useful for notifiers to produce a return value. This allows notifiers to "veto" an operation and will be used by the block layer before-write notifier. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'util/notify.c')
-rw-r--r--util/notify.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/util/notify.c b/util/notify.c
index 7b7692acb2..f215dfc214 100644
--- a/util/notify.c
+++ b/util/notify.c
@@ -39,3 +39,33 @@ void notifier_list_notify(NotifierList *list, void *data)
notifier->notify(notifier, data);
}
}
+
+void notifier_with_return_list_init(NotifierWithReturnList *list)
+{
+ QLIST_INIT(&list->notifiers);
+}
+
+void notifier_with_return_list_add(NotifierWithReturnList *list,
+ NotifierWithReturn *notifier)
+{
+ QLIST_INSERT_HEAD(&list->notifiers, notifier, node);
+}
+
+void notifier_with_return_remove(NotifierWithReturn *notifier)
+{
+ QLIST_REMOVE(notifier, node);
+}
+
+int notifier_with_return_list_notify(NotifierWithReturnList *list, void *data)
+{
+ NotifierWithReturn *notifier, *next;
+ int ret = 0;
+
+ QLIST_FOREACH_SAFE(notifier, &list->notifiers, node, next) {
+ ret = notifier->notify(notifier, data);
+ if (ret != 0) {
+ break;
+ }
+ }
+ return ret;
+}