drm/ttm: cleanup ttm_bo_mem_space

We tried this once before, but that turned out to be more
complicated than thought. With all the right prerequisites
it looks like we can do this now.
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Chunming Zhou <david1.zhou@amd.com>
Tested-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ttm/ttm_bo.c

@@ -893,13 +893,12 @@ static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
  * space, or we've evicted everything and there isn't enough space.
  */
 static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
-					uint32_t mem_type,
-					const struct ttm_place *place,
-					struct ttm_mem_reg *mem,
-					struct ttm_operation_ctx *ctx)
+				  const struct ttm_place *place,
+				  struct ttm_mem_reg *mem,
+				  struct ttm_operation_ctx *ctx)
 {
 	struct ttm_bo_device *bdev = bo->bdev;
-	struct ttm_mem_type_manager *man = &bdev->man[mem_type];
+	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
 	int ret;
 
 	do {
@@ -908,11 +907,11 @@ static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
 			return ret;
 		if (mem->mm_node)
 			break;
-		ret = ttm_mem_evict_first(bdev, mem_type, place, ctx);
+		ret = ttm_mem_evict_first(bdev, mem->mem_type, place, ctx);
 		if (unlikely(ret != 0))
 			return ret;
 	} while (1);
-	mem->mem_type = mem_type;
+
 	return ttm_bo_add_move_fence(bo, man, mem);
 }
 
@@ -960,6 +959,51 @@ static bool ttm_bo_mt_compatible(struct ttm_mem_type_manager *man,
 	return true;
 }
 
+/**
+ * ttm_bo_mem_placement - check if placement is compatible
+ * @bo: BO to find memory for
+ * @place: where to search
+ * @mem: the memory object to fill in
+ * @ctx: operation context
+ *
+ * Check if placement is compatible and fill in mem structure.
+ * Returns -EBUSY if placement won't work or negative error code.
+ * 0 when placement can be used.
+ */
+static int ttm_bo_mem_placement(struct ttm_buffer_object *bo,
+				const struct ttm_place *place,
+				struct ttm_mem_reg *mem,
+				struct ttm_operation_ctx *ctx)
+{
+	struct ttm_bo_device *bdev = bo->bdev;
+	uint32_t mem_type = TTM_PL_SYSTEM;
+	struct ttm_mem_type_manager *man;
+	uint32_t cur_flags = 0;
+	int ret;
+
+	ret = ttm_mem_type_from_place(place, &mem_type);
+	if (ret)
+		return ret;
+
+	man = &bdev->man[mem_type];
+	if (!man->has_type || !man->use_type)
+		return -EBUSY;
+
+	if (!ttm_bo_mt_compatible(man, mem_type, place, &cur_flags))
+		return -EBUSY;
+
+	cur_flags = ttm_bo_select_caching(man, bo->mem.placement, cur_flags);
+	/*
+	 * Use the access and other non-mapping-related flag bits from
+	 * the memory placement flags to the current flags
+	 */
+	ttm_flag_masked(&cur_flags, place->flags, ~TTM_PL_MASK_MEMTYPE);
+
+	mem->mem_type = mem_type;
+	mem->placement = cur_flags;
+	return 0;
+}
+
 /**
  * Creates space for memory region @mem according to its type.
  *
@@ -974,11 +1018,7 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 			struct ttm_operation_ctx *ctx)
 {
 	struct ttm_bo_device *bdev = bo->bdev;
-	struct ttm_mem_type_manager *man;
-	uint32_t mem_type = TTM_PL_SYSTEM;
-	uint32_t cur_flags = 0;
 	bool type_found = false;
-	bool type_ok = false;
 	int i, ret;
 
 	ret = reservation_object_reserve_shared(bo->resv, 1);
@@ -988,37 +1028,20 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 	mem->mm_node = NULL;
 	for (i = 0; i < placement->num_placement; ++i) {
 		const struct ttm_place *place = &placement->placement[i];
+		struct ttm_mem_type_manager *man;
 
-		ret = ttm_mem_type_from_place(place, &mem_type);
+		ret = ttm_bo_mem_placement(bo, place, mem, ctx);
+		if (ret == -EBUSY)
+			continue;
 		if (ret)
 			return ret;
-		man = &bdev->man[mem_type];
-		if (!man->has_type || !man->use_type)
-			continue;
-
-		type_ok = ttm_bo_mt_compatible(man, mem_type, place,
-						&cur_flags);
-
-		if (!type_ok)
-			continue;
 
 		type_found = true;
-		cur_flags = ttm_bo_select_caching(man, bo->mem.placement,
-						  cur_flags);
-		/*
-		 * Use the access and other non-mapping-related flag bits from
-		 * the memory placement flags to the current flags
-		 */
-		ttm_flag_masked(&cur_flags, place->flags,
-				~TTM_PL_MASK_MEMTYPE);
-
-		if (mem_type == TTM_PL_SYSTEM) {
-			mem->mem_type = mem_type;
-			mem->placement = cur_flags;
-			mem->mm_node = NULL;
+		mem->mm_node = NULL;
+		if (mem->mem_type == TTM_PL_SYSTEM)
 			return 0;
-		}
 
+		man = &bdev->man[mem->mem_type];
 		ret = (*man->func->get_node)(man, bo, place, mem);
 		if (unlikely(ret))
 			return ret;
@@ -1029,8 +1052,6 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 				(*man->func->put_node)(man, mem);
 				return ret;
 			}
-			mem->mem_type = mem_type;
-			mem->placement = cur_flags;
 			return 0;
 		}
 	}
@@ -1038,37 +1059,21 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 	for (i = 0; i < placement->num_busy_placement; ++i) {
 		const struct ttm_place *place = &placement->busy_placement[i];
 
-		ret = ttm_mem_type_from_place(place, &mem_type);
+		ret = ttm_bo_mem_placement(bo, place, mem, ctx);
+		if (ret == -EBUSY)
+			continue;
 		if (ret)
 			return ret;
-		man = &bdev->man[mem_type];
-		if (!man->has_type || !man->use_type)
-			continue;
-		if (!ttm_bo_mt_compatible(man, mem_type, place, &cur_flags))
-			continue;
 
 		type_found = true;
-		cur_flags = ttm_bo_select_caching(man, bo->mem.placement,
-						  cur_flags);
-		/*
-		 * Use the access and other non-mapping-related flag bits from
-		 * the memory placement flags to the current flags
-		 */
-		ttm_flag_masked(&cur_flags, place->flags,
-				~TTM_PL_MASK_MEMTYPE);
-
-		if (mem_type == TTM_PL_SYSTEM) {
-			mem->mem_type = mem_type;
-			mem->placement = cur_flags;
-			mem->mm_node = NULL;
+		mem->mm_node = NULL;
+		if (mem->mem_type == TTM_PL_SYSTEM)
 			return 0;
-		}
 
-		ret = ttm_bo_mem_force_space(bo, mem_type, place, mem, ctx);
-		if (ret == 0 && mem->mm_node) {
-			mem->placement = cur_flags;
+		ret = ttm_bo_mem_force_space(bo, place, mem, ctx);
+		if (ret == 0 && mem->mm_node)
 			return 0;
-		}
+
 		if (ret && ret != -EBUSY)
 			return ret;
 	}