[PATCH 2/2] dma-fence: Simply wrap dma_fence_signal_locked with dma_fence_signal

Chris Wilson chris at chris-wilson.co.uk
Fri Aug 16 15:21:52 UTC 2019


Currently dma_fence_signal() tries to avoid the spinlock and only takes
it if absolutely required to walk the callback list. However, to allow
for some users to surreptitiously insert lazy signal callbacks that
do not depend on enabling the signaling mechanism around every fence,
we always need to notify the callbacks on signaling. As such, we will
always need to take the spinlock and dma_fence_signal() effectively
becomes a clone of dma_fence_signal_locked().

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Christian König <christian.koenig at amd.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/dma-buf/dma-fence.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index ff0cd6eae766..f23eb9f19b4e 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -176,6 +176,7 @@ EXPORT_SYMBOL(dma_fence_signal_locked);
 int dma_fence_signal(struct dma_fence *fence)
 {
 	unsigned long flags;
+	int ret;
 
 	if (!fence)
 		return -EINVAL;
@@ -183,21 +184,11 @@ int dma_fence_signal(struct dma_fence *fence)
 	if (test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
 		return -EINVAL;
 
-	fence->timestamp = ktime_get();
-	set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
-	trace_dma_fence_signaled(fence);
-
-	if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags)) {
-		struct dma_fence_cb *cur, *tmp;
+	spin_lock_irqsave(fence->lock, flags);
+	ret = dma_fence_signal_locked(fence);
+	spin_unlock_irqrestore(fence->lock, flags);
 
-		spin_lock_irqsave(fence->lock, flags);
-		list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) {
-			list_del_init(&cur->node);
-			cur->func(fence, cur);
-		}
-		spin_unlock_irqrestore(fence->lock, flags);
-	}
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL(dma_fence_signal);
 
-- 
2.23.0.rc1



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