drm/virtio: trace drm_fence_emit

For most drivers, drm_fence_init is followed by drm_fence_emit
immediately.  But for our driver, they are done separately.  We also
don't know the fence seqno until drm_fence_emit.
Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20190429220825.156644-2-olvaffe@gmail.comSigned-off-by: Gerd Hoffmann <kraxel@redhat.com>

drivers/gpu/drm/virtio/virtgpu_fence.c

@@ -24,6 +24,7 @@
  */
 
 #include <drm/drmP.h>
+#include <trace/events/dma_fence.h>
 #include "virtgpu_drv.h"
 
 static const char *virtio_get_driver_name(struct dma_fence *f)
@@ -97,6 +98,8 @@ int virtio_gpu_fence_emit(struct virtio_gpu_device *vgdev,
 	list_add_tail(&fence->node, &drv->fences);
 	spin_unlock_irqrestore(&drv->lock, irq_flags);
 
+	trace_dma_fence_emit(&fence->f);
+
 	cmd_hdr->flags |= cpu_to_le32(VIRTIO_GPU_FLAG_FENCE);
 	cmd_hdr->fence_id = cpu_to_le64(fence->f.seqno);
 	return 0;