[Intel-gfx] [CI] drm/i915: Add a warning on shutdown if signal threads still active

[Chris Wilson]

When unloading the module, it is expected that we have finished
executing all requests and so the signal threads should be idle. Add a
warning in case there are any residual requests in the signaler rbtrees
at that point.

v2: We can also warn if there are any waiters

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/intel_breadcrumbs.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c
index c9c46a538edb..53ae7884babd 100644
--- a/drivers/gpu/drm/i915/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c
@@ -623,6 +623,12 @@ void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine)
 {
 	struct intel_breadcrumbs *b = &engine->breadcrumbs;
 
+	/* The engines should be idle and all requests accounted for! */
+	WARN_ON(READ_ONCE(b->first_wait));
+	WARN_ON(!RB_EMPTY_ROOT(&b->waiters));
+	WARN_ON(READ_ONCE(b->first_signal));
+	WARN_ON(!RB_EMPTY_ROOT(&b->signals));
+
 	if (!IS_ERR_OR_NULL(b->signaler))
 		kthread_stop(b->signaler);
 
-- 
2.10.2