[PATCH 23/36] 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 c80e11f56519..bdb6e28ef25e 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 020f2a5c8583..f494e65c5150 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1065,6 +1065,60 @@ void intel_engines_reset_default_submission(struct drm_i915_private *i915)
 		engine->set_default_submission(engine);
 }
 
+/**
+ * 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 2e73efd539e5..c029fc7462b9 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);
-- 
2.17.1