[RFC PATCH v1 15/16] drm/vmwgfx: use rcu in vmw_user_dmabuf_synccpu_grab

[Maarten Lankhorst <maarten.lankhorst@canonical.com>]

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_resource.c |   17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
index 20a1a866ceeb..79e950df3018 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
@@ -567,13 +567,16 @@ static int vmw_user_dmabuf_synccpu_grab(struct vmw_user_dma_buffer *user_bo,
 	int ret;
 
 	if (flags & drm_vmw_synccpu_allow_cs) {
-		ret = ttm_bo_reserve(bo, true, !!(flags & drm_vmw_synccpu_dontblock), false, 0);
-		if (!ret) {
-			ret = ttm_bo_wait(bo, false, true,
-					  !!(flags & drm_vmw_synccpu_dontblock));
-			ttm_bo_unreserve(bo);
-		}
-		return ret;
+		long lret;
+		if (flags & drm_vmw_synccpu_dontblock)
+			return reservation_object_test_signaled_rcu(bo->resv, true) ? 0 : -EBUSY;
+
+		lret = reservation_object_wait_timeout_rcu(bo->resv, true, true, MAX_SCHEDULE_TIMEOUT);
+		if (!lret)
+			return -EBUSY;
+		else if (lret < 0)
+			return lret;
+		return 0;
 	}
 
 	ret = ttm_bo_synccpu_write_grab