[PATCH 08/24] drm/i915: Move engine request retirement to intel_engine_cs

[Chris Wilson]

In the next patch, we will move ownership of the fence reference to the
submission backend and will want to drop its final reference when
retiring it from the submission backend. We will also need a catch up
when parking the engine to cleanup any residual entries in the engine
timeline. In short, move the engine retirement from i915_request.c to
intel_engine_cs.c for future use.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_request.c     | 47 +--------------------
 drivers/gpu/drm/i915/intel_engine_cs.c  | 54 +++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_ringbuffer.h |  2 +
 3 files changed, 57 insertions(+), 46 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index e6e5eea87629..4e1542a082c8 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -344,50 +344,6 @@ static void free_capture_list(struct i915_request *request)
 	}
 }
 
-static void __retire_engine_request(struct intel_engine_cs *engine,
-				    struct i915_request *rq)
-{
-	GEM_TRACE("%s(%s) fence %llx:%d, global=%d, current %d\n",
-		  __func__, engine->name,
-		  rq->fence.context, rq->fence.seqno,
-		  rq->global_seqno,
-		  intel_engine_get_seqno(engine));
-
-	GEM_BUG_ON(!i915_request_completed(rq));
-
-	local_irq_disable();
-
-	spin_lock(&engine->timeline.lock);
-	GEM_BUG_ON(!list_is_first(&rq->link, &engine->timeline.requests));
-	list_del_init(&rq->link);
-	spin_unlock(&engine->timeline.lock);
-
-	spin_lock(&rq->lock);
-	if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags))
-		dma_fence_signal_locked(&rq->fence);
-	if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &rq->fence.flags))
-		intel_engine_cancel_signaling(rq);
-	if (rq->waitboost) {
-		GEM_BUG_ON(!atomic_read(&rq->i915->gt_pm.rps.num_waiters));
-		atomic_dec(&rq->i915->gt_pm.rps.num_waiters);
-	}
-	spin_unlock(&rq->lock);
-
-	local_irq_enable();
-
-	/*
-	 * The backing object for the context is done after switching to the
-	 * *next* context. Therefore we cannot retire the previous context until
-	 * the next context has already started running. However, since we
-	 * cannot take the required locks at i915_request_submit() we
-	 * defer the unpinning of the active context to now, retirement of
-	 * the subsequent request.
-	 */
-	if (engine->last_retired_context)
-		intel_context_unpin(engine->last_retired_context);
-	engine->last_retired_context = rq->hw_context;
-}
-
 static void __retire_engine_upto(struct intel_engine_cs *engine,
 				 struct i915_request *rq)
 {
@@ -400,8 +356,7 @@ static void __retire_engine_upto(struct intel_engine_cs *engine,
 		tmp = list_first_entry(&engine->timeline.requests,
 				       typeof(*tmp), link);
 
-		GEM_BUG_ON(tmp->engine != engine);
-		__retire_engine_request(engine, tmp);
+		intel_engine_retire_request(engine, tmp);
 	} while (tmp != rq);
 }
 
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index ace93958689e..ad59499b2145 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1089,6 +1089,60 @@ void intel_engines_sanitize(struct drm_i915_private *i915)
 	}
 }
 
+/**
+ * intel_engines_retire_request: drop the request reference from the engine
+ * @engine: the engine
+ * @rq: the request
+ *
+ * This request has been completed and is part of the chain being retired by
+ * the caller, so drop any reference to it from the engine.
+ */
+void intel_engine_retire_request(struct intel_engine_cs *engine,
+				 struct i915_request *rq)
+{
+	GEM_TRACE("%s(%s) fence %llx:%d, global=%d, current %d\n",
+		  __func__, engine->name,
+		  rq->fence.context, rq->fence.seqno,
+		  rq->global_seqno,
+		  intel_engine_get_seqno(engine));
+
+	lockdep_assert_held(&engine->i915->drm.struct_mutex);
+	GEM_BUG_ON(rq->engine != engine);
+	GEM_BUG_ON(!i915_request_completed(rq));
+
+	local_irq_disable();
+
+	spin_lock(&engine->timeline.lock);
+	GEM_BUG_ON(!list_is_first(&rq->link, &engine->timeline.requests));
+	list_del_init(&rq->link);
+	spin_unlock(&engine->timeline.lock);
+
+	spin_lock(&rq->lock);
+	if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags))
+		dma_fence_signal_locked(&rq->fence);
+	if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &rq->fence.flags))
+		intel_engine_cancel_signaling(rq);
+	if (rq->waitboost) {
+		GEM_BUG_ON(!atomic_read(&rq->i915->gt_pm.rps.num_waiters));
+		atomic_dec(&rq->i915->gt_pm.rps.num_waiters);
+	}
+	spin_unlock(&rq->lock);
+
+	local_irq_enable();
+
+	/*
+	 * The backing object for the context is done after switching to the
+	 * *next* context. Therefore we cannot retire the previous context until
+	 * the next context has already started running. However, since we
+	 * cannot take the required locks at i915_request_submit() we
+	 * defer the unpinning of the active context to now, retirement of
+	 * the subsequent request.
+	 */
+	if (engine->last_retired_context)
+		intel_context_unpin(engine->last_retired_context);
+	engine->last_retired_context = rq->hw_context;
+}
+
 /**
  * intel_engines_park: called when the GT is transitioning from busy->idle
  * @i915: the i915 device
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 381c243bfc6f..95a28be1653b 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -891,6 +891,8 @@ int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine);
 int intel_init_blt_ring_buffer(struct intel_engine_cs *engine);
 int intel_init_vebox_ring_buffer(struct intel_engine_cs *engine);
 
+void intel_engine_retire_request(struct intel_engine_cs *engine,
+				 struct i915_request *rq);
 int intel_engine_stop_cs(struct intel_engine_cs *engine);
 
 u64 intel_engine_get_active_head(const struct intel_engine_cs *engine);
-- 
2.18.0.rc2