drm/i915: Add a few asserts around handling of i915_request_is_active()

Let's assert that we only call the execute callbacks on making the
request active, and that we do not execute the request without calling
the callbacks.

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/20200529085809.23691-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 0d810a62ff46a01734b8e1201d268b30cb8be533..e5aba6824e260408fc5eb59ade7f66fa431d418e 100644 (file)
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -192,6 +192,7 @@ static void __notify_execute_cb(struct i915_request *rq)
 
        lockdep_assert_held(&rq->lock);
 
+       GEM_BUG_ON(!i915_request_is_active(rq));
        if (llist_empty(&rq->execute_cb))
                return;
 
@@ -518,15 +519,15 @@ xfer:     /* We may be recursing from the signal callback of another i915 fence */
        if (!test_and_set_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags)) {
                list_move_tail(&request->sched.link, &engine->active.requests);
                clear_bit(I915_FENCE_FLAG_PQUEUE, &request->fence.flags);
+               __notify_execute_cb(request);
        }
+       GEM_BUG_ON(!llist_empty(&request->execute_cb));
 
        if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags) &&
            !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &request->fence.flags) &&
            !i915_request_enable_breadcrumb(request))
                intel_engine_signal_breadcrumbs(engine);
 
-       __notify_execute_cb(request);
-
        spin_unlock(&request->lock);
 
        return result;