drm/amdgpu: don't put the root PD into the relocated list

Instead of skipping the root PD while processing the relocated list just never
put it on the list in the first place.

This avoids walking the list all together when the root PD is the only entry
and so also avoids trying to submit a zero sized IB to the SDMA.
Signed-off-by: Christian König <christian.koenig@amd.com>
Tested-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

@@ -306,7 +306,7 @@ static void amdgpu_vm_bo_base_init(struct amdgpu_vm_bo_base *base,
 		return;
 
 	vm->bulk_moveable = false;
-	if (bo->tbo.type == ttm_bo_type_kernel)
+	if (bo->tbo.type == ttm_bo_type_kernel && bo->parent)
 		amdgpu_vm_bo_relocated(base);
 	else
 		amdgpu_vm_bo_idle(base);
@@ -660,7 +660,10 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 			amdgpu_vm_bo_moved(bo_base);
 		} else {
 			vm->update_funcs->map_table(bo);
-			amdgpu_vm_bo_relocated(bo_base);
+			if (bo->parent)
+				amdgpu_vm_bo_relocated(bo_base);
+			else
+				amdgpu_vm_bo_idle(bo_base);
 		}
 	}
 
@@ -1162,16 +1165,15 @@ uint64_t amdgpu_vm_map_gart(const dma_addr_t *pages_addr, uint64_t addr)
  *
  * @param: parameters for the update
  * @vm: requested vm
- * @parent: parent directory
  * @entry: entry to update
  *
  * Makes sure the requested entry in parent is up to date.
  */
 static int amdgpu_vm_update_pde(struct amdgpu_vm_update_params *params,
 				struct amdgpu_vm *vm,
-				struct amdgpu_vm_pt *parent,
 				struct amdgpu_vm_pt *entry)
 {
+	struct amdgpu_vm_pt *parent = amdgpu_vm_pt_parent(entry);
 	struct amdgpu_bo *bo = parent->base.bo, *pbo;
 	uint64_t pde, pt, flags;
 	unsigned level;
@@ -1233,17 +1235,13 @@ int amdgpu_vm_update_directories(struct amdgpu_device *adev,
 		return r;
 
 	while (!list_empty(&vm->relocated)) {
-		struct amdgpu_vm_pt *pt, *entry;
+		struct amdgpu_vm_pt *entry;
 
 		entry = list_first_entry(&vm->relocated, struct amdgpu_vm_pt,
 					 base.vm_status);
 		amdgpu_vm_bo_idle(&entry->base);
 
-		pt = amdgpu_vm_pt_parent(entry);
-		if (!pt)
-			continue;
-
-		r = amdgpu_vm_update_pde(&params, vm, pt, entry);
+		r = amdgpu_vm_update_pde(&params, vm, entry);
 		if (r)
 			goto error;
 	}