drm/i915: Mark GEM wedged right after marking device unplugged

As soon as a device is considered unplugged, not only prevent pending
users from accessing the device structures but also cancel all their
pending requests so all consumed resources can be cleaned up as soon
as possible.
Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190406104034.31380-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_drv.c

@@ -1907,6 +1907,13 @@ void i915_driver_unload(struct drm_device *dev)
 
 	i915_driver_unregister(dev_priv);
 
+	/*
+	 * After unregistering the device to prevent any new users, cancel
+	 * all in-flight requests so that we can quickly unbind the active
+	 * resources.
+	 */
+	i915_gem_set_wedged(dev_priv);
+
 	/* Flush any external code that still may be under the RCU lock */
 	synchronize_rcu();
 

drivers/gpu/drm/i915/i915_drv.h

@@ -2917,6 +2917,7 @@ static inline void i915_gem_drain_workqueue(struct drm_i915_private *i915)
 	int pass = 2;
 	do {
 		rcu_barrier();
+		i915_gem_drain_freed_objects(i915);
 		drain_workqueue(i915->wq);
 	} while (--pass);
 }