From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 27 Jun 2018 21:13:04 +0100
Subject: drm/i915: Only signal from interrupt when requested
Git-commit: e3be4079ea91c8b7bcb97cf44889ec5663c55fb4
Patch-mainline: v4.19-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

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

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180627201304.15817-4-chris@chris-wilson.co.uk

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 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(-)

--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1182,7 +1182,8 @@ static void notify_ring(struct intel_eng
 		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);
@@ -1205,8 +1206,11 @@ static void notify_ring(struct intel_eng
 	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);
 	}
 
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1285,7 +1285,7 @@ long i915_request_wait(struct i915_reque
 	if (flags & I915_WAIT_LOCKED)
 		add_wait_queue(errq, &reset);
 
-	intel_wait_init(&wait, rq);
+	intel_wait_init(&wait);
 
 restart:
 	do {
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -927,11 +927,10 @@ static inline u32 intel_hws_preempt_done
 /* 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)