[PATCH 1/9] drm/ttm: return -EBUSY on pipelining with no_gpu_wait

[Christian König]

Setting the no_gpu_wait flag means that the allocate BO must be available
immediately and we can't wait for any GPU operation to finish.

Signed-off-by: Christian König <christian.koenig at amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling at amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 43 +++++++++++++++++++++---------------
 1 file changed, 25 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 2070e8a57ed8..2899702139fb 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -924,7 +924,8 @@ EXPORT_SYMBOL(ttm_bo_mem_put);
  */
 static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
 				 struct ttm_mem_type_manager *man,
-				 struct ttm_mem_reg *mem)
+				 struct ttm_mem_reg *mem,
+				 bool no_wait_gpu)
 {
 	struct dma_fence *fence;
 	int ret;
@@ -933,19 +934,22 @@ static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
 	fence = dma_fence_get(man->move);
 	spin_unlock(&man->move_lock);
 
-	if (fence) {
-		reservation_object_add_shared_fence(bo->resv, fence);
+	if (!fence)
+		return 0;
 
-		ret = reservation_object_reserve_shared(bo->resv, 1);
-		if (unlikely(ret)) {
-			dma_fence_put(fence);
-			return ret;
-		}
+	if (no_wait_gpu)
+		return -EBUSY;
+
+	reservation_object_add_shared_fence(bo->resv, fence);
 
-		dma_fence_put(bo->moving);
-		bo->moving = fence;
+	ret = reservation_object_reserve_shared(bo->resv, 1);
+	if (unlikely(ret)) {
+		dma_fence_put(fence);
+		return ret;
 	}
 
+	dma_fence_put(bo->moving);
+	bo->moving = fence;
 	return 0;
 }
 
@@ -974,7 +978,7 @@ static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
 			return ret;
 	} while (1);
 
-	return ttm_bo_add_move_fence(bo, man, mem);
+	return ttm_bo_add_move_fence(bo, man, mem, ctx->no_wait_gpu);
 }
 
 static uint32_t ttm_bo_select_caching(struct ttm_mem_type_manager *man,
@@ -1116,13 +1120,16 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 		if (unlikely(ret))
 			goto error;
 
-		if (mem->mm_node) {
-			ret = ttm_bo_add_move_fence(bo, man, mem);
-			if (unlikely(ret)) {
-				(*man->func->put_node)(man, mem);
-				goto error;
-			}
-			return 0;
+		if (!mem->mm_node)
+			continue;
+
+		ret = ttm_bo_add_move_fence(bo, man, mem, ctx->no_wait_gpu);
+		if (unlikely(ret)) {
+			(*man->func->put_node)(man, mem);
+			if (ret == -EBUSY)
+				continue;
+
+			goto error;
 		}
 	}
 
-- 
2.17.1