drm/i915: Move active request tracking to a vfunc

Move active request tracking to a backend vfunc rather than assuming all
backends want to do this in the manner. In the of case execlists /
ring submission the tracking is on the physical engine while with GuC
submission it is on the context.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727002348.97202-8-matthew.brost@intel.com

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/mock_engine.c b/drivers/gpu/drm/i915/gt/mock_engine.c
index 2ddaacb4e753..2c1af030310c 100644
--- a/drivers/gpu/drm/i915/gt/mock_engine.c
+++ b/drivers/gpu/drm/i915/gt/mock_engine.c
@@ -235,6 +235,34 @@ static void mock_submit_request(struct i915_request *request)
 	spin_unlock_irqrestore(&engine->hw_lock, flags);
 }
 
+static void mock_add_to_engine(struct i915_request *rq)
+{
+	lockdep_assert_held(&rq->engine->sched_engine->lock);
+	list_move_tail(&rq->sched.link, &rq->engine->sched_engine->requests);
+}
+
+static void mock_remove_from_engine(struct i915_request *rq)
+{
+	struct intel_engine_cs *engine, *locked;
+
+	/*
+	 * Virtual engines complicate acquiring the engine timeline lock,
+	 * as their rq->engine pointer is not stable until under that
+	 * engine lock. The simple ploy we use is to take the lock then
+	 * check that the rq still belongs to the newly locked engine.
+	 */
+
+	locked = READ_ONCE(rq->engine);
+	spin_lock_irq(&locked->sched_engine->lock);
+	while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
+		spin_unlock(&locked->sched_engine->lock);
+		spin_lock(&engine->sched_engine->lock);
+		locked = engine;
+	}
+	list_del_init(&rq->sched.link);
+	spin_unlock_irq(&locked->sched_engine->lock);
+}
+
 static void mock_reset_prepare(struct intel_engine_cs *engine)
 {
 }
@@ -321,6 +349,8 @@ struct intel_engine_cs *mock_engine(struct drm_i915_private *i915,
 	engine->base.emit_flush = mock_emit_flush;
 	engine->base.emit_fini_breadcrumb = mock_emit_breadcrumb;
 	engine->base.submit_request = mock_submit_request;
+	engine->base.add_active_request = mock_add_to_engine;
+	engine->base.remove_active_request = mock_remove_from_engine;
 
 	engine->base.reset.prepare = mock_reset_prepare;
 	engine->base.reset.rewind = mock_reset_rewind;