drm/qxl: simplify qxl_fence_wait

Now that we have the new release_event wait queue we can just
use that in qxl_fence_wait() and simplify the code a lot.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20210204145712.1531203-10-kraxel@redhat.com

drivers/gpu/drm/qxl/qxl_release.c

@@ -58,55 +58,19 @@ static long qxl_fence_wait(struct dma_fence *fence, bool intr,
 			   signed long timeout)
 {
 	struct qxl_device *qdev;
-	struct qxl_release *release;
-	int count = 0, sc = 0;
-	bool have_drawable_releases;
 	unsigned long cur, end = jiffies + timeout;
 
 	qdev = container_of(fence->lock, struct qxl_device, release_lock);
-	release = container_of(fence, struct qxl_release, base);
-	have_drawable_releases = release->type == QXL_RELEASE_DRAWABLE;
-
-retry:
-	sc++;
 
 	if (dma_fence_is_signaled(fence))
 		goto signaled;
 
 	qxl_io_notify_oom(qdev);
-
-	for (count = 0; count < 11; count++) {
-		if (!qxl_queue_garbage_collect(qdev, true))
-			break;
-
-		if (dma_fence_is_signaled(fence))
-			goto signaled;
-	}
-
-	if (dma_fence_is_signaled(fence))
-		goto signaled;
-
-	if (have_drawable_releases || sc < 4) {
-		if (sc > 2)
-			/* back off */
-			usleep_range(500, 1000);
-
-		if (time_after(jiffies, end))
+	if (!wait_event_timeout(qdev->release_event,
+				dma_fence_is_signaled(fence),
+				timeout))
 		return 0;
 
-		if (have_drawable_releases && sc > 300) {
-			DMA_FENCE_WARN(fence, "failed to wait on release %llu "
-				       "after spincount %d\n",
-				       fence->context & ~0xf0000000, sc);
-			goto signaled;
-		}
-		goto retry;
-	}
-	/*
-	 * yeah, original sync_obj_wait gave up after 3 spins when
-	 * have_drawable_releases is not set.
-	 */
-
 signaled:
 	cur = jiffies;
 	if (time_after(cur, end))