From: Chris Wilson <chris@chris-wilson.co.uk>
To: dri-devel@lists.freedesktop.org
Cc: intel-gfx@lists.freedesktop.org, Chris Wilson <chris@chris-wilson.co.uk>
Subject: [PATCH 2/2] dma-buf/dma-fence: Add quick tests before dma_fence_remove_callback
Date: Wed, 15 Jul 2020 11:49:05 +0100 [thread overview]
Message-ID: <20200715104905.11006-2-chris@chris-wilson.co.uk> (raw)
In-Reply-To: <20200715104905.11006-1-chris@chris-wilson.co.uk>
When waiting with a callback on the stack, we must remove the callback
upon wait completion. Since this will be notified by the fence signal
callback, the removal often contends with the fence->lock being held by
the signaler. We can look at the list entry to see if the callback was
already signaled before we take the contended lock.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/dma-buf/dma-fence.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 8d5bdfce638e..b910d7bc0854 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -420,6 +420,9 @@ dma_fence_remove_callback(struct dma_fence *fence, struct dma_fence_cb *cb)
unsigned long flags;
bool ret;
+ if (list_empty(&cb->node))
+ return false;
+
spin_lock_irqsave(fence->lock, flags);
ret = !list_empty(&cb->node);
--
2.20.1
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next prev parent reply other threads:[~2020-07-15 10:49 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-15 10:49 [PATCH 1/2] dma-buf/dma-fence: Trim dma_fence_add_callback() Chris Wilson
2020-07-15 10:49 ` Chris Wilson [this message]
2020-07-15 12:10 ` [Intel-gfx] [PATCH 2/2] dma-buf/dma-fence: Add quick tests before dma_fence_remove_callback Daniel Vetter
2020-07-15 12:21 ` Chris Wilson
2020-07-15 12:40 ` Chris Wilson
2020-07-15 14:03 ` Daniel Vetter
2020-07-15 14:37 ` Chris Wilson
2020-07-15 14:46 ` Daniel Vetter
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