From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 2 Jan 2018 15:12:25 +0000
Subject: drm/i915: Assert all signalers we depended on did indeed signal
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Git-commit: 83cc84c5a848748d4bb190bc179a7620491a925f
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Back up our comment that all signalers should have been signaled before
we ourselves were retired with an assert to that effect.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180102151235.3949-9-chris@chris-wilson.co.uk

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/i915/i915_gem_request.c |    9 ++++++++-
 drivers/gpu/drm/i915/i915_gem_request.h |    8 ++++++++
 drivers/gpu/drm/i915/intel_lrc.c        |    2 +-
 3 files changed, 17 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -161,12 +161,16 @@ i915_priotree_fini(struct drm_i915_priva
 
 	GEM_BUG_ON(!list_empty(&pt->link));
 
-	/* Everyone we depended upon (the fences we wait to be signaled)
+	/*
+	 * Everyone we depended upon (the fences we wait to be signaled)
 	 * should retire before us and remove themselves from our list.
 	 * However, retirement is run independently on each timeline and
 	 * so we may be called out-of-order.
 	 */
 	list_for_each_entry_safe(dep, next, &pt->signalers_list, signal_link) {
+		GEM_BUG_ON(!i915_priotree_signaled(dep->signaler));
+		GEM_BUG_ON(!list_empty(&dep->dfs_link));
+
 		list_del(&dep->wait_link);
 		if (dep->flags & I915_DEPENDENCY_ALLOC)
 			i915_dependency_free(i915, dep);
@@ -174,6 +178,9 @@ i915_priotree_fini(struct drm_i915_priva
 
 	/* Remove ourselves from everyone who depends upon us */
 	list_for_each_entry_safe(dep, next, &pt->waiters_list, wait_link) {
+		GEM_BUG_ON(dep->signaler != pt);
+		GEM_BUG_ON(!list_empty(&dep->dfs_link));
+
 		list_del(&dep->signal_link);
 		if (dep->flags & I915_DEPENDENCY_ALLOC)
 			i915_dependency_free(i915, dep);
--- a/drivers/gpu/drm/i915/i915_gem_request.h
+++ b/drivers/gpu/drm/i915/i915_gem_request.h
@@ -329,6 +329,14 @@ i915_gem_request_completed(const struct
 	return __i915_gem_request_completed(req, seqno);
 }
 
+static inline bool i915_priotree_signaled(const struct i915_priotree *pt)
+{
+	const struct drm_i915_gem_request *rq =
+		container_of(pt, const struct drm_i915_gem_request, priotree);
+
+	return i915_gem_request_completed(rq);
+}
+
 /* We treat requests as fences. This is not be to confused with our
  * "fence registers" but pipeline synchronisation objects ala GL_ARB_sync.
  * We use the fences to synchronize access from the CPU with activity on the
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1045,7 +1045,7 @@ static void execlists_schedule(struct dr
 		 * engines.
 		 */
 		list_for_each_entry(p, &pt->signalers_list, signal_link) {
-			if (i915_gem_request_completed(pt_to_request(p->signaler)))
+			if (i915_priotree_signaled(p->signaler))
 				continue;
 
 			GEM_BUG_ON(p->signaler->priority < pt->priority);