drm/i915: Move idle barrier cleanup into engine-pm

Now that we now longer need to guarantee that the active callback is
under the struct_mutex, we can lift it out of the i915_gem_park() and
into the engine parking itself.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-7-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gem/i915_gem_pm.c

@@ -11,29 +11,10 @@
 #include "i915_drv.h"
 #include "i915_globals.h"
 
-static void call_idle_barriers(struct intel_engine_cs *engine)
-{
-	struct llist_node *node, *next;
-
-	llist_for_each_safe(node, next, llist_del_all(&engine->barrier_tasks)) {
-		struct dma_fence_cb *cb =
-			container_of((struct list_head *)node,
-				     typeof(*cb), node);
-
-		cb->func(NULL, cb);
-	}
-}
-
 static void i915_gem_park(struct drm_i915_private *i915)
 {
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-
 	lockdep_assert_held(&i915->drm.struct_mutex);
 
-	for_each_engine(engine, i915, id)
-		call_idle_barriers(engine); /* cleanup after wedging */
-
 	i915_vma_parked(i915);
 
 	i915_globals_park();

drivers/gpu/drm/i915/gt/intel_engine_pm.c

@@ -124,6 +124,19 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
 	return result;
 }
 
+static void call_idle_barriers(struct intel_engine_cs *engine)
+{
+	struct llist_node *node, *next;
+
+	llist_for_each_safe(node, next, llist_del_all(&engine->barrier_tasks)) {
+		struct dma_fence_cb *cb =
+			container_of((struct list_head *)node,
+				     typeof(*cb), node);
+
+		cb->func(NULL, cb);
+	}
+}
+
 static int __engine_park(struct intel_wakeref *wf)
 {
 	struct intel_engine_cs *engine =
@@ -143,6 +156,8 @@ static int __engine_park(struct intel_wakeref *wf)
 
 	GEM_TRACE("%s\n", engine->name);
 
+	call_idle_barriers(engine); /* cleanup after wedging */
+
 	intel_engine_disarm_breadcrumbs(engine);
 	intel_engine_pool_park(&engine->pool);
 

drivers/gpu/drm/i915/i915_active.c

@@ -693,6 +693,7 @@ void i915_active_acquire_barrier(struct i915_active *ref)
 		rb_link_node(&node->node, parent, p);
 		rb_insert_color(&node->node, &ref->tree);
 
+		GEM_BUG_ON(!intel_engine_pm_is_awake(engine));
 		llist_add(barrier_to_ll(node), &engine->barrier_tasks);
 		intel_engine_pm_put(engine);
 	}