drm/i915: Pull assert_forcewake_active() underneath the lock

Make no assumption that something in the background is not acquiring the
fw_domain -- but we still do not track owner so assume that any active
domain is intended by the caller.
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/20190707151135.11700-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_uncore.c

@@ -747,6 +747,8 @@ void assert_forcewakes_active(struct intel_uncore *uncore,
 	if (!uncore->funcs.force_wake_get)
 		return;
 
+	spin_lock_irq(&uncore->lock);
+
 	assert_rpm_wakelock_held(uncore->rpm);
 
 	fw_domains &= uncore->fw_domains;
@@ -770,6 +772,8 @@ void assert_forcewakes_active(struct intel_uncore *uncore,
 			 domain->id, actual))
 			break;
 	}
+
+	spin_unlock_irq(&uncore->lock);
 }
 
 /* We give fast paths for the really cool registers */