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Message-Id: <1362098606-26469-16-git-send-email-john.stultz@linaro.org>
Date: Thu, 28 Feb 2013 16:43:11 -0800
From: John Stultz <john.stultz@...aro.org>
To: lkml <linux-kernel@...r.kernel.org>
Cc: Erik Gilling <konkers@...roid.com>,
Maarten Lankhorst <maarten.lankhorst@...onical.com>,
Daniel Vetter <daniel.vetter@...ll.ch>,
Rob Clark <robclark@...il.com>,
Sumit Semwal <sumit.semwal@...aro.org>,
Greg KH <gregkh@...uxfoundation.org>,
dri-devel@...ts.freedesktop.org,
Android Kernel Team <kernel-team@...roid.com>,
John Stultz <john.stultz@...aro.org>
Subject: [PATCH 15/30] staging: sync: Add reference counting to timelines
From: Erik Gilling <konkers@...roid.com>
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.
Cc: Maarten Lankhorst <maarten.lankhorst@...onical.com>
Cc: Erik Gilling <konkers@...roid.com>
Cc: Daniel Vetter <daniel.vetter@...ll.ch>
Cc: Rob Clark <robclark@...il.com>
Cc: Sumit Semwal <sumit.semwal@...aro.org>
Cc: Greg KH <gregkh@...uxfoundation.org>
Cc: dri-devel@...ts.freedesktop.org
Cc: Android Kernel Team <kernel-team@...roid.com>
Signed-off-by: Erik Gilling <konkers@...roid.com>
[jstultz: Squished in compiler warning fix]
Signed-off-by: John Stultz <john.stultz@...aro.org>
---
drivers/staging/android/sync.c | 29 +++++++++++++----------------
drivers/staging/android/sync.h | 2 ++
2 files changed, 15 insertions(+), 16 deletions(-)
diff --git a/drivers/staging/android/sync.c b/drivers/staging/android/sync.c
index 7d4e9aa..61c27bd 100644
--- a/drivers/staging/android/sync.c
+++ b/drivers/staging/android/sync.c
@@ -51,6 +51,7 @@ struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
if (obj == NULL)
return NULL;
+ kref_init(&obj->kref);
obj->ops = ops;
strlcpy(obj->name, name, sizeof(obj->name));
@@ -68,8 +69,10 @@ struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
}
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)
@@ -84,17 +87,14 @@ static void sync_timeline_free(struct sync_timeline *obj)
void sync_timeline_destroy(struct sync_timeline *obj)
{
- 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);
@@ -114,7 +114,6 @@ static void sync_timeline_remove_pt(struct sync_pt *pt)
{
struct sync_timeline *obj = pt->parent;
unsigned long flags;
- bool needs_freeing = false;
spin_lock_irqsave(&obj->active_list_lock, flags);
if (!list_empty(&pt->active_list))
@@ -124,13 +123,8 @@ static void sync_timeline_remove_pt(struct sync_pt *pt)
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 +171,7 @@ struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size)
return NULL;
INIT_LIST_HEAD(&pt->active_list);
+ kref_get(&parent->kref);
sync_timeline_add_pt(parent, pt);
return pt;
@@ -190,6 +185,8 @@ void sync_pt_free(struct sync_pt *pt)
sync_timeline_remove_pt(pt);
+ kref_put(&pt->parent->kref, sync_timeline_free);
+
kfree(pt);
}
EXPORT_SYMBOL(sync_pt_free);
diff --git a/drivers/staging/android/sync.h b/drivers/staging/android/sync.h
index 00c9bae..15863a6 100644
--- a/drivers/staging/android/sync.h
+++ b/drivers/staging/android/sync.h
@@ -80,6 +80,7 @@ struct sync_timeline_ops {
/**
* struct sync_timeline - sync object
+ * @kref: reference count on fence.
* @ops: ops that define the implementaiton of the sync_timeline
* @name: name of the sync_timeline. Useful for debugging
* @destoryed: set when sync_timeline is destroyed
@@ -90,6 +91,7 @@ struct sync_timeline_ops {
* @sync_timeline_list: membership in global sync_timeline_list
*/
struct sync_timeline {
+ struct kref kref;
const struct sync_timeline_ops *ops;
char name[32];
--
1.7.10.4
--
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