[RFC 11/44] drm/i915: Added scheduler hook into i915_seqno_passed()

[John.C.Harrison@Intel.com]

From: John Harrison <John.C.Harrison@Intel.com>

The GPU scheduler can cause seqno values to become out of order. This means that
a straight forward 'is seqno X > seqno Y' test is no longer valid. Instead, a
call into the scheduler must be made to see if the value being queried is known
to be out of order.
---
 drivers/gpu/drm/i915/i915_drv.h       |   23 ++++++++++++++++++++++-
 drivers/gpu/drm/i915/i915_gem.c       |   14 +++++++-------
 drivers/gpu/drm/i915/i915_irq.c       |    4 ++--
 drivers/gpu/drm/i915/i915_scheduler.c |   20 ++++++++++++++++++++
 drivers/gpu/drm/i915/i915_scheduler.h |    3 +++
 5 files changed, 54 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 6e592d3..0977653 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2214,14 +2214,35 @@ int i915_gem_dumb_create(struct drm_file *file_priv,
 			 struct drm_mode_create_dumb *args);
 int i915_gem_mmap_gtt(struct drm_file *file_priv, struct drm_device *dev,
 		      uint32_t handle, uint64_t *offset);
+
+bool i915_scheduler_is_seqno_in_flight(struct intel_engine_cs *ring,
+				uint32_t seqno, bool *completed);
+
 /**
  * Returns true if seq1 is later than seq2.
  */
 static inline bool
-i915_seqno_passed(uint32_t seq1, uint32_t seq2)
+i915_seqno_passed(struct intel_engine_cs *ring, uint32_t seq1, uint32_t seq2)
 {
+#ifdef CONFIG_DRM_I915_SCHEDULER
+	bool    completed;
+
+	if (i915_scheduler_is_seqno_in_flight(ring, seq2, &completed))
+		return completed;
+#endif
+
 	return (int32_t)(seq1 - seq2) >= 0;
 }
+static inline int32_t
+i915_compare_seqno_values(uint32_t seq1, uint32_t seq2)
+{
+	int32_t	diff = seq1 - seq2;
+
+	if (!diff)
+		return 0;
+
+	return (diff > 0) ? 1 : -1;
+}
 
 int __must_check i915_gem_get_seqno(struct drm_device *dev, u32 *seqno);
 int __must_check i915_gem_set_seqno(struct drm_device *dev, u32 seqno);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7e53446..fece5e7 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1165,7 +1165,7 @@ static int __wait_seqno(struct intel_engine_cs *ring, u32 seqno,
 
 	WARN(dev_priv->pm.irqs_disabled, "IRQs disabled\n");
 
-	if (i915_seqno_passed(ring->get_seqno(ring, true), seqno))
+	if (i915_seqno_passed(ring, ring->get_seqno(ring, true), seqno))
 		return 0;
 
 	timeout_expire = timeout ? jiffies + timespec_to_jiffies_timeout(timeout) : 0;
@@ -1201,7 +1201,7 @@ static int __wait_seqno(struct intel_engine_cs *ring, u32 seqno,
 			break;
 		}
 
-		if (i915_seqno_passed(ring->get_seqno(ring, false), seqno)) {
+		if (i915_seqno_passed(ring, ring->get_seqno(ring, false), seqno)) {
 			ret = 0;
 			break;
 		}
@@ -2243,7 +2243,7 @@ i915_gem_object_retire(struct drm_i915_gem_object *obj)
 	if (ring == NULL)
 		return;
 
-	if (i915_seqno_passed(ring->get_seqno(ring, true),
+	if (i915_seqno_passed(ring, ring->get_seqno(ring, true),
 			      obj->last_read_seqno))
 		i915_gem_object_move_to_inactive(obj);
 }
@@ -2489,7 +2489,7 @@ i915_gem_find_active_request(struct intel_engine_cs *ring)
 	completed_seqno = ring->get_seqno(ring, false);
 
 	list_for_each_entry(request, &ring->request_list, list) {
-		if (i915_seqno_passed(completed_seqno, request->seqno))
+		if (i915_seqno_passed(ring, completed_seqno, request->seqno))
 			continue;
 
 		return request;
@@ -2620,7 +2620,7 @@ i915_gem_retire_requests_ring(struct intel_engine_cs *ring)
 	 */
 
 	list_for_each_entry_safe(req, req_next, &ring->request_list, list) {
-		if (!i915_seqno_passed(seqno, req->seqno))
+		if (!i915_seqno_passed(ring, seqno, req->seqno))
 			continue;
 
 		trace_i915_gem_request_retire(ring, req->seqno);
@@ -2639,14 +2639,14 @@ i915_gem_retire_requests_ring(struct intel_engine_cs *ring)
 	 * before we free the context associated with the requests.
 	 */
 	list_for_each_entry_safe(obj, obj_next, &ring->active_list, ring_list) {
-		if (!i915_seqno_passed(seqno, obj->last_read_seqno))
+		if (!i915_seqno_passed(ring, seqno, obj->last_read_seqno))
 			continue;
 
 		i915_gem_object_move_to_inactive(obj);
 	}
 
 	if (unlikely(ring->trace_irq_seqno &&
-		     i915_seqno_passed(seqno, ring->trace_irq_seqno))) {
+		     i915_seqno_passed(ring, seqno, ring->trace_irq_seqno))) {
 		ring->irq_put(ring);
 		ring->trace_irq_seqno = 0;
 	}
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 00358f9..eff08a3e 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2750,7 +2750,7 @@ static bool
 ring_idle(struct intel_engine_cs *ring, u32 seqno)
 {
 	return (list_empty(&ring->request_list) ||
-		i915_seqno_passed(seqno, ring_last_seqno(ring)));
+		i915_seqno_passed(ring, seqno, ring_last_seqno(ring)));
 }
 
 static bool
@@ -2862,7 +2862,7 @@ static int semaphore_passed(struct intel_engine_cs *ring)
 	if (ctl & RING_WAIT_SEMAPHORE && semaphore_passed(signaller) < 0)
 		return -1;
 
-	return i915_seqno_passed(signaller->get_seqno(signaller, false), seqno);
+	return i915_seqno_passed(ring, signaller->get_seqno(signaller, false), seqno);
 }
 
 static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index 9ec0225..e9aa566 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -49,6 +49,26 @@ int i915_scheduler_init(struct drm_device *dev)
 	return 0;
 }
 
+bool i915_scheduler_is_seqno_in_flight(struct intel_engine_cs *ring,
+			       uint32_t seqno, bool *completed)
+{
+	struct drm_i915_private *dev_priv = ring->dev->dev_private;
+	struct i915_scheduler   *scheduler = dev_priv->scheduler;
+	bool                    found = false;
+	unsigned long           flags;
+
+	if (!scheduler)
+		return false;
+
+	spin_lock_irqsave(&scheduler->lock, flags);
+
+	/* Do stuff... */
+
+	spin_unlock_irqrestore(&scheduler->lock, flags);
+
+	return found;
+}
+
 #else   /* CONFIG_DRM_I915_SCHEDULER */
 
 int i915_scheduler_init(struct drm_device *dev)
diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
index bbe1934..67260b7 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.h
+++ b/drivers/gpu/drm/i915/i915_scheduler.h
@@ -35,6 +35,9 @@ struct i915_scheduler {
 	uint32_t    index;
 };
 
+bool        i915_scheduler_is_seqno_in_flight(struct intel_engine_cs *ring,
+					      uint32_t seqno, bool *completed);
+
 #endif  /* CONFIG_DRM_I915_SCHEDULER */
 
 #endif  /* _I915_SCHEDULER_H_ */
-- 
1.7.9.5