[PATCH 55/69] drm/i915: Only signal from interrupt when requested

Chris Wilson chris at chris-wilson.co.uk
Fri May 4 10:22:14 UTC 2018


Avoid calling dma_fence_signal() from inside the interrupt if we haven't
enabled signaling on the request.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_irq.c         | 8 ++++++--
 drivers/gpu/drm/i915/i915_request.c     | 2 +-
 drivers/gpu/drm/i915/intel_ringbuffer.h | 5 ++---
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 1c073de0c62c..bf9d6de81107 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -915,7 +915,8 @@ static void notify_ring(struct intel_engine_cs *engine)
 		if (i915_seqno_passed(seqno, wait->seqno)) {
 			struct i915_request *waiter = wait->request;
 
-			if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
+			if (waiter &&
+			    !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
 				      &waiter->fence.flags) &&
 			    intel_wait_check_request(wait, waiter))
 				rq = i915_request_get(waiter);
@@ -936,8 +937,11 @@ static void notify_ring(struct intel_engine_cs *engine)
 	spin_unlock(&engine->breadcrumbs.irq_lock);
 
 	if (rq) {
-		dma_fence_signal(&rq->fence);
+		spin_lock(&rq->lock);
+		dma_fence_signal_locked(&rq->fence);
 		GEM_BUG_ON(!i915_request_completed(rq));
+		spin_unlock(&rq->lock);
+
 		i915_request_put(rq);
 	}
 
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index f472a34735aa..a6caa8ac995d 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1296,7 +1296,7 @@ long i915_request_wait(struct i915_request *rq,
 	if (flags & I915_WAIT_LOCKED)
 		add_wait_queue(errq, &reset);
 
-	intel_wait_init(&wait, rq);
+	intel_wait_init(&wait);
 
 restart:
 	do {
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index ad2980d9b708..03ac5d89a3dd 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -928,11 +928,10 @@ static inline u32 intel_hws_preempt_done_address(struct intel_engine_cs *engine)
 /* intel_breadcrumbs.c -- user interrupt bottom-half for waiters */
 int intel_engine_init_breadcrumbs(struct intel_engine_cs *engine);
 
-static inline void intel_wait_init(struct intel_wait *wait,
-				   struct i915_request *rq)
+static inline void intel_wait_init(struct intel_wait *wait)
 {
 	wait->tsk = current;
-	wait->request = rq;
+	wait->request = NULL;
 }
 
 static inline void intel_wait_init_for_seqno(struct intel_wait *wait, u32 seqno)
-- 
2.17.0



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