sync: add reference counting to timelines
If a timeline is destroyed while fences still hold pts on it, the reworked
fence release handler can cause the timeline to be freed before all it's points
are freed.
Change-Id: I1cd8ddb638eded7db9db446ff6b37f3dd165d6c4
Signed-off-by: Erik Gilling <konkers@android.com>
Signed-off-by: Ajay Dudani <adudani@codeaurora.org>
diff --git a/drivers/base/sync.c b/drivers/base/sync.c
index be808b0..ad3fee0 100644
--- a/drivers/base/sync.c
+++ b/drivers/base/sync.c
@@ -51,6 +51,7 @@
if (obj == NULL)
return NULL;
+ kref_init(&obj->kref);
obj->ops = ops;
strlcpy(obj->name, name, sizeof(obj->name));
@@ -68,8 +69,10 @@
}
EXPORT_SYMBOL(sync_timeline_create);
-static void sync_timeline_free(struct sync_timeline *obj)
+static void sync_timeline_free(struct kref *kref)
{
+ struct sync_timeline *obj =
+ container_of(kref, struct sync_timeline, kref);
unsigned long flags;
if (obj->ops->release_obj)
@@ -87,14 +90,14 @@
unsigned long flags;
bool needs_freeing;
- spin_lock_irqsave(&obj->child_list_lock, flags);
obj->destroyed = true;
- needs_freeing = list_empty(&obj->child_list_head);
- spin_unlock_irqrestore(&obj->child_list_lock, flags);
- if (needs_freeing)
- sync_timeline_free(obj);
- else
+ /*
+ * If this is not the last reference, signal any children
+ * that their parent is going away.
+ */
+
+ if (!kref_put(&obj->kref, sync_timeline_free))
sync_timeline_signal(obj);
}
EXPORT_SYMBOL(sync_timeline_destroy);
@@ -124,13 +127,8 @@
spin_lock_irqsave(&obj->child_list_lock, flags);
if (!list_empty(&pt->child_list)) {
list_del_init(&pt->child_list);
- needs_freeing = obj->destroyed &&
- list_empty(&obj->child_list_head);
}
spin_unlock_irqrestore(&obj->child_list_lock, flags);
-
- if (needs_freeing)
- sync_timeline_free(obj);
}
void sync_timeline_signal(struct sync_timeline *obj)
@@ -177,6 +175,7 @@
return NULL;
INIT_LIST_HEAD(&pt->active_list);
+ kref_get(&parent->kref);
sync_timeline_add_pt(parent, pt);
return pt;
@@ -190,6 +189,8 @@
sync_timeline_remove_pt(pt);
+ kref_put(&pt->parent->kref, sync_timeline_free);
+
kfree(pt);
}
EXPORT_SYMBOL(sync_pt_free);