4 files changed, 57 insertions, 34 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
index cbedba857d43..d907d538176e 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -142,6 +142,18 @@ static void add_retire(struct intel_breadcrumbs *b, struct intel_timeline *tl)
 	intel_engine_add_retire(engine, tl);
 }
 
+static void __signal_request(struct i915_request *rq, struct list_head *signals)
+{
+	GEM_BUG_ON(!test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags));
+	clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);
+
+	if (!__dma_fence_signal(&rq->fence))
+		return;
+
+	i915_request_get(rq);
+	list_add_tail(&rq->signal_link, signals);
+}
+
 static void signal_irq_work(struct irq_work *work)
 {
 	struct intel_breadcrumbs *b = container_of(work, typeof(*b), irq_work);
@@ -155,6 +167,8 @@ static void signal_irq_work(struct irq_work *work)
 	if (b->irq_armed && list_empty(&b->signalers))
 		__intel_breadcrumbs_disarm_irq(b);
 
+	list_splice_init(&b->signaled_requests, &signal);
+
 	list_for_each_entry_safe(ce, cn, &b->signalers, signal_link) {
 		GEM_BUG_ON(list_empty(&ce->signals));
 
@@ -163,24 +177,15 @@ static void signal_irq_work(struct irq_work *work)
 				list_entry(pos, typeof(*rq), signal_link);
 
 			GEM_BUG_ON(!check_signal_order(ce, rq));
-
 			if (!__request_completed(rq))
 				break;
 
-			GEM_BUG_ON(!test_bit(I915_FENCE_FLAG_SIGNAL,
-					     &rq->fence.flags));
-			clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);
-
-			if (!__dma_fence_signal(&rq->fence))
-				continue;
-
 			/*
 			 * Queue for execution after dropping the signaling
 			 * spinlock as the callback chain may end up adding
 			 * more signalers to the same context or engine.
 			 */
-			i915_request_get(rq);
-			list_add_tail(&rq->signal_link, &signal);
+			__signal_request(rq, &signal);
 		}
 
 		/*
@@ -255,6 +260,7 @@ void intel_engine_init_breadcrumbs(struct intel_engine_cs *engine)
 
 	spin_lock_init(&b->irq_lock);
 	INIT_LIST_HEAD(&b->signalers);
+	INIT_LIST_HEAD(&b->signaled_requests);
 
 	init_irq_work(&b->irq_work, signal_irq_work);
 }
@@ -274,6 +280,32 @@ void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine)
 	spin_unlock_irqrestore(&b->irq_lock, flags);
 }
 
+void intel_engine_transfer_stale_breadcrumbs(struct intel_engine_cs *engine,
+					     struct intel_context *ce)
+{
+	struct intel_breadcrumbs *b = &engine->breadcrumbs;
+	unsigned long flags;
+
+	spin_lock_irqsave(&b->irq_lock, flags);
+	if (!list_empty(&ce->signals)) {
+		struct i915_request *rq, *next;
+
+		/* Queue for executing the signal callbacks in the irq_work */
+		list_for_each_entry_safe(rq, next, &ce->signals, signal_link) {
+			GEM_BUG_ON(rq->engine != engine);
+			GEM_BUG_ON(!__request_completed(rq));
+
+			__signal_request(rq, &b->signaled_requests);
+		}
+
+		INIT_LIST_HEAD(&ce->signals);
+		list_del_init(&ce->signal_link);
+
+		irq_work_queue(&b->irq_work);
+	}
+	spin_unlock_irqrestore(&b->irq_lock, flags);
+}
+
 void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine)
 {
 }
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h
index cb789c8bf06b..9bf6d4989968 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine.h
@@ -238,6 +238,9 @@ intel_engine_signal_breadcrumbs(struct intel_engine_cs *engine)
 void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine);
 void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);
 
+void intel_engine_transfer_stale_breadcrumbs(struct intel_engine_cs *engine,
+					     struct intel_context *ce);
+
 void intel_engine_print_breadcrumbs(struct intel_engine_cs *engine,
 				    struct drm_printer *p);
 
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index c39db7e249e2..2b6cdf47d428 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -377,6 +377,8 @@ struct intel_engine_cs {
 		spinlock_t irq_lock;
 		struct list_head signalers;
 
+		struct list_head signaled_requests;
+
 		struct irq_work irq_work; /* for use from inside irq_lock */
 
 		unsigned int irq_enabled;
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 32fdb7cb3ae8..87e6c5bdd2dc 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1812,30 +1812,16 @@ static bool virtual_matches(const struct virtual_engine *ve,
 	return true;
 }
 
-static void virtual_xfer_breadcrumbs(struct virtual_engine *ve,
-				     struct i915_request *rq)
+static void virtual_xfer_breadcrumbs(struct virtual_engine *ve)
 {
-	struct intel_engine_cs *old = ve->siblings[0];
-
-	/* All unattached (rq->engine == old) must already be completed */
-
-	spin_lock(&old->breadcrumbs.irq_lock);
-	if (!list_empty(&ve->context.signal_link)) {
-		list_del_init(&ve->context.signal_link);
-
-		/*
-		 * We cannot acquire the new engine->breadcrumbs.irq_lock
-		 * (as we are holding a breadcrumbs.irq_lock already),
-		 * so attach this request to the signaler on submission.
-		 * The queued irq_work will occur when we finally drop
-		 * the engine->active.lock after dequeue.
-		 */
-		set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &rq->fence.flags);
-
-		/* Also transfer the pending irq_work for the old breadcrumb. */
-		intel_engine_signal_breadcrumbs(rq->engine);
-	}
-	spin_unlock(&old->breadcrumbs.irq_lock);
+	/*
+	 * All the outstanding signals on ve->siblings[0] must have
+	 * been completed, just pending the interrupt handler. As those
+	 * signals still refer to the old sibling (via rq->engine), we must
+	 * transfer those to the old irq_worker to keep our locking
+	 * consistent.
+	 */
+	intel_engine_transfer_stale_breadcrumbs(ve->siblings[0], &ve->context);
 }
 
 #define for_each_waiter(p__, rq__) \
@@ -2270,7 +2256,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 									engine);
 
 				if (!list_empty(&ve->context.signals))
-					virtual_xfer_breadcrumbs(ve, rq);
+					virtual_xfer_breadcrumbs(ve);
 
 				/*
 				 * Move the bound engine to the top of the list