[Intel-gfx] [PATCH] drm/i915: Do a quick check on whether the fence is already signaled first

[Chris Wilson]

Now that we try to signal the fence from inside the interrupt handler,
when we reach the signaler thread, the fence is most likely already
signaled. Skip manipulating the bottom-half locks if this is so.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/intel_breadcrumbs.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c
index 8f52fd5f6102..5f79c8135b3f 100644
--- a/drivers/gpu/drm/i915/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c
@@ -616,9 +616,12 @@ static int intel_breadcrumbs_signaler(void *arg)
 			request = i915_gem_request_get_rcu(request);
 		rcu_read_unlock();
 		if (signal_complete(request)) {
-			local_bh_disable();
-			dma_fence_signal(&request->fence);
-			local_bh_enable(); /* kick start the tasklets */
+			if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
+				      &request->fence.flags)) {
+				local_bh_disable();
+				dma_fence_signal(&request->fence);
+				local_bh_enable(); /* kick start the tasklet */
+			}
 
 			spin_lock_irq(&b->rb_lock);
 
-- 
2.11.0