If the runcount is non-zero in eventhandler_deregister() then one or more

threads are executing the eventhandler, sleep in this case to make it safe for
module unload. If the runcount was up then an entry would have been marked
EHE_DEAD_PRIORITY so use this as a trigger to do the wakeup in
eventhandler_prune_list().

Reviewed by:	jhb

1 files changed, 7 insertions, 4 deletions

diff --git a/sys/kern/subr_eventhandler.c b/sys/kern/subr_eventhandler.c
index f9c8ead..37c482c 100644
--- a/sys/kern/subr_eventhandler.c
+++ b/sys/kern/subr_eventhandler.c
@@ -178,6 +178,8 @@ eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag)
 		ep->ee_priority = EHE_DEAD_PRIORITY;
 	}
     }
+    while (list->el_runcount > 0)
+	    mtx_sleep(list, &list->el_lock, 0, "evhrm", 0);
     EHL_UNLOCK(list);
 }
 
@@ -225,16 +227,17 @@ void
 eventhandler_prune_list(struct eventhandler_list *list)
 {
     struct eventhandler_entry *ep, *en;
+    int pruned = 0;
 
     CTR2(KTR_EVH, "%s: pruning list \"%s\"", __func__, list->el_name);
     EHL_LOCK_ASSERT(list, MA_OWNED);
-    ep = TAILQ_FIRST(&list->el_entries);
-    while (ep != NULL) {
-	en = TAILQ_NEXT(ep, ee_link);
+    TAILQ_FOREACH_SAFE(ep, &list->el_entries, ee_link, en) {
 	if (ep->ee_priority == EHE_DEAD_PRIORITY) {
 	    TAILQ_REMOVE(&list->el_entries, ep, ee_link);
 	    free(ep, M_EVENTHANDLER);
+	    pruned++;
 	}
-	ep = en;
     }
+    if (pruned > 0)
+	    wakeup(list);
 }