drm/i915: Abandon oom quickly if killed by a signal

Whilst waiting to obtain our locks for the last resort shrinking before
an oom, we check whether or not a fatal signal was pending. If there was,
we do not need to keep waiting as the oom will be aborted.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem.c

@@ -5194,8 +5194,11 @@ i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
 	bool was_interruptible;
 	bool unlock;
 
-	while (!i915_gem_shrinker_lock(dev, &unlock) && --timeout)
+	while (!i915_gem_shrinker_lock(dev, &unlock) && --timeout) {
 		schedule_timeout_killable(1);
+		if (fatal_signal_pending(current))
+			return NOTIFY_DONE;
+	}
 	if (timeout == 0) {
 		pr_err("Unable to purge GPU memory due lock contention.\n");
 		return NOTIFY_DONE;