drm/ttm: return -EBUSY on pipelining with no_gpu_wait (v2)

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.

v2: squash in mem leak fix, rebase
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ttm/ttm_bo.c

@@ -925,7 +925,8 @@ 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;
@@ -934,7 +935,12 @@ 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) {
+	if (!fence)
+		return 0;
+
+	if (no_wait_gpu)
+		return -EBUSY;
+
 	dma_resv_add_shared_fence(bo->base.resv, fence);
 
 	ret = dma_resv_reserve_shared(bo->base.resv, 1);
@@ -945,8 +951,6 @@ static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
 
 	dma_fence_put(bo->moving);
 	bo->moving = fence;
-	}
-
 	return 0;
 }
 
@@ -977,7 +981,7 @@ 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,
@@ -1119,15 +1123,19 @@ 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 (!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;
 		}
 		return 0;
 	}
-	}
 
 	for (i = 0; i < placement->num_busy_placement; ++i) {
 		const struct ttm_place *place = &placement->busy_placement[i];